mirror of https://gitee.com/openkylin/linux.git
2310 lines
72 KiB
XML
2310 lines
72 KiB
XML
<title>Kernel Demux API</title>
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<para>The kernel demux API defines a driver-internal interface for registering low-level,
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hardware specific driver to a hardware independent demux layer. It is only of interest for
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DVB device driver writers. The header file for this API is named <emphasis role="tt">demux.h</emphasis> and located in
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<emphasis role="tt">drivers/media/dvb/dvb-core</emphasis>.
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</para>
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<para>Maintainer note: This section must be reviewed. It is probably out of date.
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</para>
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<section id="kernel_demux_data_types">
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<title>Kernel Demux Data Types</title>
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<section id="dmx_success_t">
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<title>dmx_success_t</title>
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<programlisting>
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typedef enum {
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DMX_OK = 0, /⋆ Received Ok ⋆/
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DMX_LENGTH_ERROR, /⋆ Incorrect length ⋆/
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DMX_OVERRUN_ERROR, /⋆ Receiver ring buffer overrun ⋆/
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DMX_CRC_ERROR, /⋆ Incorrect CRC ⋆/
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DMX_FRAME_ERROR, /⋆ Frame alignment error ⋆/
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DMX_FIFO_ERROR, /⋆ Receiver FIFO overrun ⋆/
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DMX_MISSED_ERROR /⋆ Receiver missed packet ⋆/
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} dmx_success_t;
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</programlisting>
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</section>
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<section id="ts_filter_types">
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<title>TS filter types</title>
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<programlisting>
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ TS packet reception ⋆/
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ TS filter type for set_type() ⋆/
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#define TS_PACKET 1 /⋆ send TS packets (188 bytes) to callback (default) ⋆/
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#define TS_PAYLOAD_ONLY 2 /⋆ in case TS_PACKET is set, only send the TS
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payload (<=184 bytes per packet) to callback ⋆/
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#define TS_DECODER 4 /⋆ send stream to built-in decoder (if present) ⋆/
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</programlisting>
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</section>
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<section id="dmx_ts_pes_t">
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<title>dmx_ts_pes_t</title>
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<para>The structure
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</para>
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<programlisting>
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typedef enum
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{
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DMX_TS_PES_AUDIO, /⋆ also send packets to audio decoder (if it exists) ⋆/
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DMX_TS_PES_VIDEO, /⋆ ... ⋆/
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DMX_TS_PES_TELETEXT,
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DMX_TS_PES_SUBTITLE,
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DMX_TS_PES_PCR,
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DMX_TS_PES_OTHER,
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} dmx_ts_pes_t;
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</programlisting>
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<para>describes the PES type for filters which write to a built-in decoder. The correspond (and
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should be kept identical) to the types in the demux device.
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</para>
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<programlisting>
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struct dmx_ts_feed_s {
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int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/
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struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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int (⋆set) (struct dmx_ts_feed_s⋆ feed,
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__u16 pid,
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size_t callback_length,
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size_t circular_buffer_size,
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int descramble,
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struct timespec timeout);
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int (⋆start_filtering) (struct dmx_ts_feed_s⋆ feed);
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int (⋆stop_filtering) (struct dmx_ts_feed_s⋆ feed);
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int (⋆set_type) (struct dmx_ts_feed_s⋆ feed,
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int type,
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dmx_ts_pes_t pes_type);
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};
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typedef struct dmx_ts_feed_s dmx_ts_feed_t;
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</programlisting>
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<programlisting>
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ PES packet reception (not supported yet) ⋆/
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/⋆--------------------------------------------------------------------------⋆/
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typedef struct dmx_pes_filter_s {
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struct dmx_pes_s⋆ parent; /⋆ Back-pointer ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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} dmx_pes_filter_t;
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</programlisting>
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<programlisting>
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typedef struct dmx_pes_feed_s {
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int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/
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struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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int (⋆set) (struct dmx_pes_feed_s⋆ feed,
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__u16 pid,
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size_t circular_buffer_size,
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int descramble,
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struct timespec timeout);
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int (⋆start_filtering) (struct dmx_pes_feed_s⋆ feed);
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int (⋆stop_filtering) (struct dmx_pes_feed_s⋆ feed);
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int (⋆allocate_filter) (struct dmx_pes_feed_s⋆ feed,
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dmx_pes_filter_t⋆⋆ filter);
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int (⋆release_filter) (struct dmx_pes_feed_s⋆ feed,
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dmx_pes_filter_t⋆ filter);
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} dmx_pes_feed_t;
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</programlisting>
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<programlisting>
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typedef struct {
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__u8 filter_value [DMX_MAX_FILTER_SIZE];
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__u8 filter_mask [DMX_MAX_FILTER_SIZE];
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struct dmx_section_feed_s⋆ parent; /⋆ Back-pointer ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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} dmx_section_filter_t;
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</programlisting>
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<programlisting>
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struct dmx_section_feed_s {
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int is_filtering; /⋆ Set to non-zero when filtering in progress ⋆/
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struct dmx_demux_s⋆ parent; /⋆ Back-pointer ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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int (⋆set) (struct dmx_section_feed_s⋆ feed,
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__u16 pid,
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size_t circular_buffer_size,
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int descramble,
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int check_crc);
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int (⋆allocate_filter) (struct dmx_section_feed_s⋆ feed,
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dmx_section_filter_t⋆⋆ filter);
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int (⋆release_filter) (struct dmx_section_feed_s⋆ feed,
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dmx_section_filter_t⋆ filter);
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int (⋆start_filtering) (struct dmx_section_feed_s⋆ feed);
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int (⋆stop_filtering) (struct dmx_section_feed_s⋆ feed);
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};
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typedef struct dmx_section_feed_s dmx_section_feed_t;
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ Callback functions ⋆/
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/⋆--------------------------------------------------------------------------⋆/
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typedef int (⋆dmx_ts_cb) ( __u8 ⋆ buffer1,
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size_t buffer1_length,
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__u8 ⋆ buffer2,
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size_t buffer2_length,
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dmx_ts_feed_t⋆ source,
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dmx_success_t success);
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typedef int (⋆dmx_section_cb) ( __u8 ⋆ buffer1,
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size_t buffer1_len,
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__u8 ⋆ buffer2,
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size_t buffer2_len,
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dmx_section_filter_t ⋆ source,
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dmx_success_t success);
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typedef int (⋆dmx_pes_cb) ( __u8 ⋆ buffer1,
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size_t buffer1_len,
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__u8 ⋆ buffer2,
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size_t buffer2_len,
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dmx_pes_filter_t⋆ source,
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dmx_success_t success);
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ DVB Front-End ⋆/
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/⋆--------------------------------------------------------------------------⋆/
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typedef enum {
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DMX_OTHER_FE = 0,
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DMX_SATELLITE_FE,
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DMX_CABLE_FE,
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DMX_TERRESTRIAL_FE,
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DMX_LVDS_FE,
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DMX_ASI_FE, /⋆ DVB-ASI interface ⋆/
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DMX_MEMORY_FE
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} dmx_frontend_source_t;
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typedef struct {
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/⋆ The following char⋆ fields point to NULL terminated strings ⋆/
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char⋆ id; /⋆ Unique front-end identifier ⋆/
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char⋆ vendor; /⋆ Name of the front-end vendor ⋆/
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char⋆ model; /⋆ Name of the front-end model ⋆/
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struct list_head connectivity_list; /⋆ List of front-ends that can
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be connected to a particular
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demux ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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dmx_frontend_source_t source;
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} dmx_frontend_t;
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/⋆--------------------------------------------------------------------------⋆/
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/⋆ MPEG-2 TS Demux ⋆/
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/⋆--------------------------------------------------------------------------⋆/
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/⋆
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⋆ Flags OR'ed in the capabilites field of struct dmx_demux_s.
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⋆/
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#define DMX_TS_FILTERING 1
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#define DMX_PES_FILTERING 2
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#define DMX_SECTION_FILTERING 4
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#define DMX_MEMORY_BASED_FILTERING 8 /⋆ write() available ⋆/
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#define DMX_CRC_CHECKING 16
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#define DMX_TS_DESCRAMBLING 32
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#define DMX_SECTION_PAYLOAD_DESCRAMBLING 64
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#define DMX_MAC_ADDRESS_DESCRAMBLING 128
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</programlisting>
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</section>
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<section id="demux_demux_t">
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<title>demux_demux_t</title>
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<programlisting>
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/⋆
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⋆ DMX_FE_ENTRY(): Casts elements in the list of registered
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⋆ front-ends from the generic type struct list_head
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⋆ to the type ⋆ dmx_frontend_t
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⋆.
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⋆/
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#define DMX_FE_ENTRY(list) list_entry(list, dmx_frontend_t, connectivity_list)
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struct dmx_demux_s {
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/⋆ The following char⋆ fields point to NULL terminated strings ⋆/
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char⋆ id; /⋆ Unique demux identifier ⋆/
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char⋆ vendor; /⋆ Name of the demux vendor ⋆/
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char⋆ model; /⋆ Name of the demux model ⋆/
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__u32 capabilities; /⋆ Bitfield of capability flags ⋆/
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dmx_frontend_t⋆ frontend; /⋆ Front-end connected to the demux ⋆/
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struct list_head reg_list; /⋆ List of registered demuxes ⋆/
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void⋆ priv; /⋆ Pointer to private data of the API client ⋆/
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int users; /⋆ Number of users ⋆/
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int (⋆open) (struct dmx_demux_s⋆ demux);
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int (⋆close) (struct dmx_demux_s⋆ demux);
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int (⋆write) (struct dmx_demux_s⋆ demux, const char⋆ buf, size_t count);
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int (⋆allocate_ts_feed) (struct dmx_demux_s⋆ demux,
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dmx_ts_feed_t⋆⋆ feed,
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dmx_ts_cb callback);
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int (⋆release_ts_feed) (struct dmx_demux_s⋆ demux,
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dmx_ts_feed_t⋆ feed);
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int (⋆allocate_pes_feed) (struct dmx_demux_s⋆ demux,
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dmx_pes_feed_t⋆⋆ feed,
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dmx_pes_cb callback);
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int (⋆release_pes_feed) (struct dmx_demux_s⋆ demux,
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dmx_pes_feed_t⋆ feed);
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int (⋆allocate_section_feed) (struct dmx_demux_s⋆ demux,
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dmx_section_feed_t⋆⋆ feed,
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dmx_section_cb callback);
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int (⋆release_section_feed) (struct dmx_demux_s⋆ demux,
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dmx_section_feed_t⋆ feed);
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int (⋆descramble_mac_address) (struct dmx_demux_s⋆ demux,
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__u8⋆ buffer1,
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size_t buffer1_length,
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__u8⋆ buffer2,
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size_t buffer2_length,
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__u16 pid);
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int (⋆descramble_section_payload) (struct dmx_demux_s⋆ demux,
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__u8⋆ buffer1,
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size_t buffer1_length,
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__u8⋆ buffer2, size_t buffer2_length,
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__u16 pid);
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int (⋆add_frontend) (struct dmx_demux_s⋆ demux,
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dmx_frontend_t⋆ frontend);
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int (⋆remove_frontend) (struct dmx_demux_s⋆ demux,
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dmx_frontend_t⋆ frontend);
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struct list_head⋆ (⋆get_frontends) (struct dmx_demux_s⋆ demux);
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int (⋆connect_frontend) (struct dmx_demux_s⋆ demux,
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dmx_frontend_t⋆ frontend);
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int (⋆disconnect_frontend) (struct dmx_demux_s⋆ demux);
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/⋆ added because js cannot keep track of these himself ⋆/
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int (⋆get_pes_pids) (struct dmx_demux_s⋆ demux, __u16 ⋆pids);
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};
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typedef struct dmx_demux_s dmx_demux_t;
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</programlisting>
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</section>
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<section id="demux_directory">
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<title>Demux directory</title>
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<programlisting>
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/⋆
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⋆ DMX_DIR_ENTRY(): Casts elements in the list of registered
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⋆ demuxes from the generic type struct list_head⋆ to the type dmx_demux_t
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⋆.
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⋆/
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#define DMX_DIR_ENTRY(list) list_entry(list, dmx_demux_t, reg_list)
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int dmx_register_demux (dmx_demux_t⋆ demux);
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int dmx_unregister_demux (dmx_demux_t⋆ demux);
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struct list_head⋆ dmx_get_demuxes (void);
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</programlisting>
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</section></section>
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<section id="demux_directory_api">
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<title>Demux Directory API</title>
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<para>The demux directory is a Linux kernel-wide facility for registering and accessing the
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MPEG-2 TS demuxes in the system. Run-time registering and unregistering of demux drivers
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is possible using this API.
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</para>
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<para>All demux drivers in the directory implement the abstract interface dmx_demux_t.
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</para>
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<section
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role="subsection"><title>dmx_register_demux()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This function makes a demux driver interface available to the Linux kernel. It is
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usually called by the init_module() function of the kernel module that contains
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the demux driver. The caller of this function is responsible for allocating
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dynamic or static memory for the demux structure and for initializing its fields
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before calling this function. The memory allocated for the demux structure
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must not be freed before calling dmx_unregister_demux(),</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int dmx_register_demux ( dmx_demux_t ⋆demux )</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_demux_t*
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demux</para>
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</entry><entry
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align="char">
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<para>Pointer to the demux structure.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EEXIST</para>
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</entry><entry
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align="char">
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<para>A demux with the same value of the id field already stored
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in the directory.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-ENOSPC</para>
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</entry><entry
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align="char">
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<para>No space left in the directory.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section><section
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role="subsection"><title>dmx_unregister_demux()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This function is called to indicate that the given demux interface is no
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longer available. The caller of this function is responsible for freeing the
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memory of the demux structure, if it was dynamically allocated before calling
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dmx_register_demux(). The cleanup_module() function of the kernel module
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that contains the demux driver should call this function. Note that this function
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fails if the demux is currently in use, i.e., release_demux() has not been called
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for the interface.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int dmx_unregister_demux ( dmx_demux_t ⋆demux )</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_demux_t*
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demux</para>
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</entry><entry
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align="char">
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<para>Pointer to the demux structure which is to be
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unregistered.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>ENODEV</para>
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</entry><entry
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align="char">
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<para>The specified demux is not registered in the demux
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directory.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>EBUSY</para>
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</entry><entry
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align="char">
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<para>The specified demux is currently in use.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section><section
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role="subsection"><title>dmx_get_demuxes()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>Provides the caller with the list of registered demux interfaces, using the
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standard list structure defined in the include file linux/list.h. The include file
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demux.h defines the macro DMX_DIR_ENTRY() for converting an element of
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the generic type struct list_head* to the type dmx_demux_t*. The caller must
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not free the memory of any of the elements obtained via this function call.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>struct list_head ⋆dmx_get_demuxes ()</para>
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</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>none</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>struct list_head *</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>A list of demux interfaces, or NULL in the case of an
|
|
empty list.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section></section>
|
|
<section id="demux_api">
|
|
<title>Demux API</title>
|
|
<para>The demux API should be implemented for each demux in the system. It is used to select
|
|
the TS source of a demux and to manage the demux resources. When the demux
|
|
client allocates a resource via the demux API, it receives a pointer to the API of that
|
|
resource.
|
|
</para>
|
|
<para>Each demux receives its TS input from a DVB front-end or from memory, as set via the
|
|
demux API. In a system with more than one front-end, the API can be used to select one of
|
|
the DVB front-ends as a TS source for a demux, unless this is fixed in the HW platform. The
|
|
demux API only controls front-ends regarding their connections with demuxes; the APIs
|
|
used to set the other front-end parameters, such as tuning, are not defined in this
|
|
document.
|
|
</para>
|
|
<para>The functions that implement the abstract interface demux should be defined static or
|
|
module private and registered to the Demux Directory for external access. It is not necessary
|
|
to implement every function in the demux_t struct, however (for example, a demux interface
|
|
might support Section filtering, but not TS or PES filtering). The API client is expected to
|
|
check the value of any function pointer before calling the function: the value of NULL means
|
|
“function not available”.
|
|
</para>
|
|
<para>Whenever the functions of the demux API modify shared data, the possibilities of lost
|
|
update and race condition problems should be addressed, e.g. by protecting parts of code with
|
|
mutexes. This is especially important on multi-processor hosts.
|
|
</para>
|
|
<para>Note that functions called from a bottom half context must not sleep, at least in the 2.2.x
|
|
kernels. Even a simple memory allocation can result in a kernel thread being put to sleep if
|
|
swapping is needed. For example, the Linux kernel calls the functions of a network device
|
|
interface from a bottom half context. Thus, if a demux API function is called from network
|
|
device code, the function must not sleep.
|
|
</para>
|
|
|
|
|
|
<section id="kdapi_fopen">
|
|
<title>open()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function reserves the demux for use by the caller and, if necessary,
|
|
initializes the demux. When the demux is no longer needed, the function close()
|
|
should be called. It should be possible for multiple clients to access the demux
|
|
at the same time. Thus, the function implementation should increment the
|
|
demux usage count when open() is called and decrement it when close() is
|
|
called.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int open ( demux_t⋆ demux );</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t* demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EUSERS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Maximum usage count reached.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section>
|
|
<section id="kdapi_fclose">
|
|
<title>close()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function reserves the demux for use by the caller and, if necessary,
|
|
initializes the demux. When the demux is no longer needed, the function close()
|
|
should be called. It should be possible for multiple clients to access the demux
|
|
at the same time. Thus, the function implementation should increment the
|
|
demux usage count when open() is called and decrement it when close() is
|
|
called.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int close(demux_t⋆ demux);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t* demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENODEV</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The demux was not in use.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section>
|
|
<section id="kdapi_fwrite">
|
|
<title>write()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function provides the demux driver with a memory buffer containing TS
|
|
packets. Instead of receiving TS packets from the DVB front-end, the demux
|
|
driver software will read packets from memory. Any clients of this demux
|
|
with active TS, PES or Section filters will receive filtered data via the Demux
|
|
callback API (see 0). The function returns when all the data in the buffer has
|
|
been consumed by the demux. Demux hardware typically cannot read TS from
|
|
memory. If this is the case, memory-based filtering has to be implemented
|
|
entirely in software.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int write(demux_t⋆ demux, const char⋆ buf, size_t
|
|
count);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t* demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>const char* buf</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS data in kernel-space memory.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the TS data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The command is not implemented.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>allocate_ts_feed()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Allocates a new TS feed, which is used to filter the TS packets carrying a
|
|
certain PID. The TS feed normally corresponds to a hardware PID filter on the
|
|
demux chip.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int allocate_ts_feed(dmx_demux_t⋆ demux,
|
|
dmx_ts_feed_t⋆⋆ feed, dmx_ts_cb callback);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t* demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t**
|
|
feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS feed API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_ts_cb callback</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the callback function for passing received TS
|
|
packet</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No more TS feeds available.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The command is not implemented.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>release_ts_feed()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Releases the resources allocated with allocate_ts_feed(). Any filtering in
|
|
progress on the TS feed should be stopped before calling this function.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int release_ts_feed(dmx_demux_t⋆ demux,
|
|
dmx_ts_feed_t⋆ feed);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t* demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t* feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS feed API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>allocate_section_feed()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Allocates a new section feed, i.e. a demux resource for filtering and receiving
|
|
sections. On platforms with hardware support for section filtering, a section
|
|
feed is directly mapped to the demux HW. On other platforms, TS packets are
|
|
first PID filtered in hardware and a hardware section filter then emulated in
|
|
software. The caller obtains an API pointer of type dmx_section_feed_t as an
|
|
out parameter. Using this API the caller can set filtering parameters and start
|
|
receiving sections.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int allocate_section_feed(dmx_demux_t⋆ demux,
|
|
dmx_section_feed_t ⋆⋆feed, dmx_section_cb callback);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t *demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_section_feed_t
|
|
**feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the section feed API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_section_cb
|
|
callback</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the callback function for passing received
|
|
sections.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No more section feeds available.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The command is not implemented.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>release_section_feed()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Releases the resources allocated with allocate_section_feed(), including
|
|
allocated filters. Any filtering in progress on the section feed should be stopped
|
|
before calling this function.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int release_section_feed(dmx_demux_t⋆ demux,
|
|
dmx_section_feed_t ⋆feed);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>demux_t *demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_section_feed_t
|
|
*feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the section feed API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>descramble_mac_address()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function runs a descrambling algorithm on the destination MAC
|
|
address field of a DVB Datagram Section, replacing the original address
|
|
with its un-encrypted version. Otherwise, the description on the function
|
|
descramble_section_payload() applies also to this function.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int descramble_mac_address(dmx_demux_t⋆ demux, __u8
|
|
⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2,
|
|
size_t buffer2_length, __u16 pid);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t
|
|
*demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8 *buffer1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the first byte of the section.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer1_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the section data, including headers and CRC,
|
|
in buffer1.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8* buffer2</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the tail of the section data, or NULL. The
|
|
pointer has a non-NULL value if the section wraps past
|
|
the end of a circular buffer.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer2_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the section data, including headers and CRC,
|
|
in buffer2.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u16 pid</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The PID on which the section was received. Useful
|
|
for obtaining the descrambling key, e.g. from a DVB
|
|
Common Access facility.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No descrambling facility available.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>descramble_section_payload()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function runs a descrambling algorithm on the payload of a DVB
|
|
Datagram Section, replacing the original payload with its un-encrypted
|
|
version. The function will be called from the demux API implementation;
|
|
the API client need not call this function directly. Section-level scrambling
|
|
algorithms are currently standardized only for DVB-RCC (return channel
|
|
over 2-directional cable TV network) systems. For all other DVB networks,
|
|
encryption schemes are likely to be proprietary to each data broadcaster. Thus,
|
|
it is expected that this function pointer will have the value of NULL (i.e.,
|
|
function not available) in most demux API implementations. Nevertheless, it
|
|
should be possible to use the function pointer as a hook for dynamically adding
|
|
a “plug-in” descrambling facility to a demux driver.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>While this function is not needed with hardware-based section descrambling,
|
|
the descramble_section_payload function pointer can be used to override the
|
|
default hardware-based descrambling algorithm: if the function pointer has a
|
|
non-NULL value, the corresponding function should be used instead of any
|
|
descrambling hardware.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int descramble_section_payload(dmx_demux_t⋆ demux,
|
|
__u8 ⋆buffer1, size_t buffer1_length, __u8 ⋆buffer2,
|
|
size_t buffer2_length, __u16 pid);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t
|
|
*demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8 *buffer1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the first byte of the section.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer1_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the section data, including headers and CRC,
|
|
in buffer1.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8 *buffer2</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the tail of the section data, or NULL. The
|
|
pointer has a non-NULL value if the section wraps past
|
|
the end of a circular buffer.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer2_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the section data, including headers and CRC,
|
|
in buffer2.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u16 pid</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The PID on which the section was received. Useful
|
|
for obtaining the descrambling key, e.g. from a DVB
|
|
Common Access facility.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No descrambling facility available.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>add_frontend()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Registers a connectivity between a demux and a front-end, i.e., indicates that
|
|
the demux can be connected via a call to connect_frontend() to use the given
|
|
front-end as a TS source. The client of this function has to allocate dynamic or
|
|
static memory for the frontend structure and initialize its fields before calling
|
|
this function. This function is normally called during the driver initialization.
|
|
The caller must not free the memory of the frontend struct before successfully
|
|
calling remove_frontend().</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int add_frontend(dmx_demux_t ⋆demux, dmx_frontend_t
|
|
⋆frontend);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*
|
|
demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_frontend_t*
|
|
frontend</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the front-end instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EEXIST</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>A front-end with the same value of the id field already
|
|
registered.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINUSE</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The demux is in use.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOMEM</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No more front-ends can be added.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>remove_frontend()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Indicates that the given front-end, registered by a call to add_frontend(), can
|
|
no longer be connected as a TS source by this demux. The function should be
|
|
called when a front-end driver or a demux driver is removed from the system.
|
|
If the front-end is in use, the function fails with the return value of -EBUSY.
|
|
After successfully calling this function, the caller can free the memory of
|
|
the frontend struct if it was dynamically allocated before the add_frontend()
|
|
operation.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int remove_frontend(dmx_demux_t⋆ demux,
|
|
dmx_frontend_t⋆ frontend);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*
|
|
demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_frontend_t*
|
|
frontend</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the front-end instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The front-end is in use, i.e. a call to connect_frontend()
|
|
has not been followed by a call to disconnect_frontend().</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>get_frontends()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Provides the APIs of the front-ends that have been registered for this demux.
|
|
Any of the front-ends obtained with this call can be used as a parameter for
|
|
connect_frontend().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>The include file demux.h contains the macro DMX_FE_ENTRY() for
|
|
converting an element of the generic type struct list_head* to the type
|
|
dmx_frontend_t*. The caller must not free the memory of any of the elements
|
|
obtained via this function call.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>struct list_head⋆ get_frontends(dmx_demux_t⋆ demux);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*
|
|
demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>A list of front-end interfaces, or NULL in the case of an
|
|
empty list.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>connect_frontend()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Connects the TS output of the front-end to the input of the demux. A demux
|
|
can only be connected to a front-end registered to the demux with the function
|
|
add_frontend().</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>It may or may not be possible to connect multiple demuxes to the same
|
|
front-end, depending on the capabilities of the HW platform. When not used,
|
|
the front-end should be released by calling disconnect_frontend().</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int connect_frontend(dmx_demux_t⋆ demux,
|
|
dmx_frontend_t⋆ frontend);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*
|
|
demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_frontend_t*
|
|
frontend</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the front-end instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EBUSY</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The front-end is in use.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>disconnect_frontend()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Disconnects the demux and a front-end previously connected by a
|
|
connect_frontend() call.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int disconnect_frontend(dmx_demux_t⋆ demux);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_demux_t*
|
|
demux</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the demux API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section></section>
|
|
<section id="demux_callback_api">
|
|
<title>Demux Callback API</title>
|
|
<para>This kernel-space API comprises the callback functions that deliver filtered data to the
|
|
demux client. Unlike the other APIs, these API functions are provided by the client and called
|
|
from the demux code.
|
|
</para>
|
|
<para>The function pointers of this abstract interface are not packed into a structure as in the
|
|
other demux APIs, because the callback functions are registered and used independent
|
|
of each other. As an example, it is possible for the API client to provide several
|
|
callback functions for receiving TS packets and no callbacks for PES packets or
|
|
sections.
|
|
</para>
|
|
<para>The functions that implement the callback API need not be re-entrant: when a demux
|
|
driver calls one of these functions, the driver is not allowed to call the function again before
|
|
the original call returns. If a callback is triggered by a hardware interrupt, it is recommended
|
|
to use the Linux “bottom half” mechanism or start a tasklet instead of making the callback
|
|
function call directly from a hardware interrupt.
|
|
</para>
|
|
|
|
<section
|
|
role="subsection"><title>dmx_ts_cb()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function, provided by the client of the demux API, is called from the
|
|
demux code. The function is only called when filtering on this TS feed has
|
|
been enabled using the start_filtering() function.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>Any TS packets that match the filter settings are copied to a circular buffer. The
|
|
filtered TS packets are delivered to the client using this callback function. The
|
|
size of the circular buffer is controlled by the circular_buffer_size parameter
|
|
of the set() function in the TS Feed API. It is expected that the buffer1 and
|
|
buffer2 callback parameters point to addresses within the circular buffer, but
|
|
other implementations are also possible. Note that the called party should not
|
|
try to free the memory the buffer1 and buffer2 parameters point to.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>When this function is called, the buffer1 parameter typically points to the
|
|
start of the first undelivered TS packet within a circular buffer. The buffer2
|
|
buffer parameter is normally NULL, except when the received TS packets have
|
|
crossed the last address of the circular buffer and ”wrapped” to the beginning
|
|
of the buffer. In the latter case the buffer1 parameter would contain an address
|
|
within the circular buffer, while the buffer2 parameter would contain the first
|
|
address of the circular buffer.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>The number of bytes delivered with this function (i.e. buffer1_length +
|
|
buffer2_length) is usually equal to the value of callback_length parameter
|
|
given in the set() function, with one exception: if a timeout occurs before
|
|
receiving callback_length bytes of TS data, any undelivered packets are
|
|
immediately delivered to the client by calling this function. The timeout
|
|
duration is controlled by the set() function in the TS Feed API.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>If a TS packet is received with errors that could not be fixed by the TS-level
|
|
forward error correction (FEC), the Transport_error_indicator flag of the TS
|
|
packet header should be set. The TS packet should not be discarded, as
|
|
the error can possibly be corrected by a higher layer protocol. If the called
|
|
party is slow in processing the callback, it is possible that the circular buffer
|
|
eventually fills up. If this happens, the demux driver should discard any TS
|
|
packets received while the buffer is full. The error should be indicated to the
|
|
client on the next callback by setting the success parameter to the value of
|
|
DMX_OVERRUN_ERROR.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>The type of data returned to the callback can be selected by the new
|
|
function int (*set_type) (struct dmx_ts_feed_s* feed, int type, dmx_ts_pes_t
|
|
pes_type) which is part of the dmx_ts_feed_s struct (also cf. to the
|
|
include file ost/demux.h) The type parameter decides if the raw TS packet
|
|
(TS_PACKET) or just the payload (TS_PACKET—TS_PAYLOAD_ONLY)
|
|
should be returned. If additionally the TS_DECODER bit is set the stream
|
|
will also be sent to the hardware MPEG decoder. In this case, the second
|
|
flag decides as what kind of data the stream should be interpreted. The
|
|
possible choices are one of DMX_TS_PES_AUDIO, DMX_TS_PES_VIDEO,
|
|
DMX_TS_PES_TELETEXT, DMX_TS_PES_SUBTITLE,
|
|
DMX_TS_PES_PCR, or DMX_TS_PES_OTHER.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int dmx_ts_cb(__u8⋆ buffer1, size_t buffer1_length,
|
|
__u8⋆ buffer2, size_t buffer2_length, dmx_ts_feed_t⋆
|
|
source, dmx_success_t success);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>__u8* buffer1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the start of the filtered TS packets.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer1_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the TS data in buffer1.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8* buffer2</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the tail of the filtered TS packets, or NULL.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer2_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the TS data in buffer2.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t*
|
|
source</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Indicates which TS feed is the source of the callback.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_success_t
|
|
success</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Indicates if there was an error in TS reception.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Continue filtering.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Stop filtering - has the same effect as a call to
|
|
stop_filtering() on the TS Feed API.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>dmx_section_cb()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function, provided by the client of the demux API, is called from the
|
|
demux code. The function is only called when filtering of sections has been
|
|
enabled using the function start_filtering() of the section feed API. When the
|
|
demux driver has received a complete section that matches at least one section
|
|
filter, the client is notified via this callback function. Normally this function is
|
|
called for each received section; however, it is also possible to deliver multiple
|
|
sections with one callback, for example when the system load is high. If an
|
|
error occurs while receiving a section, this function should be called with
|
|
the corresponding error type set in the success field, whether or not there is
|
|
data to deliver. The Section Feed implementation should maintain a circular
|
|
buffer for received sections. However, this is not necessary if the Section Feed
|
|
API is implemented as a client of the TS Feed API, because the TS Feed
|
|
implementation then buffers the received data. The size of the circular buffer
|
|
can be configured using the set() function in the Section Feed API. If there
|
|
is no room in the circular buffer when a new section is received, the section
|
|
must be discarded. If this happens, the value of the success parameter should
|
|
be DMX_OVERRUN_ERROR on the next callback.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int dmx_section_cb(__u8⋆ buffer1, size_t
|
|
buffer1_length, __u8⋆ buffer2, size_t
|
|
buffer2_length, dmx_section_filter_t⋆ source,
|
|
dmx_success_t success);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>__u8* buffer1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the start of the filtered section, e.g. within the
|
|
circular buffer of the demux driver.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer1_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the filtered section data in buffer1, including
|
|
headers and CRC.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u8* buffer2</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the tail of the filtered section data, or NULL.
|
|
Useful to handle the wrapping of a circular buffer.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t buffer2_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Length of the filtered section data in buffer2, including
|
|
headers and CRC.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_section_filter_t*
|
|
filter</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Indicates the filter that triggered the callback.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>dmx_success_t
|
|
success</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Indicates if there was an error in section reception.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Continue filtering.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-1</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Stop filtering - has the same effect as a call to
|
|
stop_filtering() on the Section Feed API.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section></section>
|
|
<section id="ts_feed_api">
|
|
<title>TS Feed API</title>
|
|
<para>A TS feed is typically mapped to a hardware PID filter on the demux chip.
|
|
Using this API, the client can set the filtering properties to start/stop filtering TS
|
|
packets on a particular TS feed. The API is defined as an abstract interface of the type
|
|
dmx_ts_feed_t.
|
|
</para>
|
|
<para>The functions that implement the interface should be defined static or module private. The
|
|
client can get the handle of a TS feed API by calling the function allocate_ts_feed() in the
|
|
demux API.
|
|
</para>
|
|
|
|
<section
|
|
role="subsection"><title>set()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>This function sets the parameters of a TS feed. Any filtering in progress on the
|
|
TS feed must be stopped before calling this function.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int set ( dmx_ts_feed_t⋆ feed, __u16 pid, size_t
|
|
callback_length, size_t circular_buffer_size, int
|
|
descramble, struct timespec timeout);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t* feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS feed API and instance data.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>__u16 pid</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>PID value to filter. Only the TS packets carrying the
|
|
specified PID will be passed to the API client.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t
|
|
callback_length</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Number of bytes to deliver with each call to the
|
|
dmx_ts_cb() callback function. The value of this
|
|
parameter should be a multiple of 188.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>size_t
|
|
circular_buffer_size</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Size of the circular buffer for the filtered TS packets.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>int descramble</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>If non-zero, descramble the filtered TS packets.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>struct timespec
|
|
timeout</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Maximum time to wait before delivering received TS
|
|
packets to the client.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOMEM</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Not enough memory for the requested buffer size.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-ENOSYS</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>No descrambling facility available for TS.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>start_filtering()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Starts filtering TS packets on this TS feed, according to its settings. The PID
|
|
value to filter can be set by the API client. All matching TS packets are
|
|
delivered asynchronously to the client, using the callback function registered
|
|
with allocate_ts_feed().</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int start_filtering(dmx_ts_feed_t⋆ feed);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t* feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS feed API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
|
|
</section><section
|
|
role="subsection"><title>stop_filtering()</title>
|
|
<para>DESCRIPTION
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>Stops filtering TS packets on this TS feed.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>SYNOPSIS
|
|
</para>
|
|
<informaltable><tgroup cols="1"><tbody><row><entry
|
|
align="char">
|
|
<para>int stop_filtering(dmx_ts_feed_t⋆ feed);</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>PARAMETERS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>dmx_ts_feed_t* feed</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Pointer to the TS feed API and instance data.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
<para>RETURNS
|
|
</para>
|
|
<informaltable><tgroup cols="2"><tbody><row><entry
|
|
align="char">
|
|
<para>0</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>The function was completed without errors.</para>
|
|
</entry>
|
|
</row><row><entry
|
|
align="char">
|
|
<para>-EINVAL</para>
|
|
</entry><entry
|
|
align="char">
|
|
<para>Bad parameter.</para>
|
|
</entry>
|
|
</row></tbody></tgroup></informaltable>
|
|
</section></section>
|
|
<section id="section_feed_api">
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<title>Section Feed API</title>
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<para>A section feed is a resource consisting of a PID filter and a set of section filters. Using this
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API, the client can set the properties of a section feed and to start/stop filtering. The API is
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defined as an abstract interface of the type dmx_section_feed_t. The functions that implement
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the interface should be defined static or module private. The client can get the handle of
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a section feed API by calling the function allocate_section_feed() in the demux
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API.
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</para>
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<para>On demux platforms that provide section filtering in hardware, the Section Feed API
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implementation provides a software wrapper for the demux hardware. Other platforms may
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support only PID filtering in hardware, requiring that TS packets are converted to sections in
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software. In the latter case the Section Feed API implementation can be a client of the TS
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Feed API.
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</para>
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</section>
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<section id="kdapi_set">
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<title>set()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This function sets the parameters of a section feed. Any filtering in progress on
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the section feed must be stopped before calling this function. If descrambling
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is enabled, the payload_scrambling_control and address_scrambling_control
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fields of received DVB datagram sections should be observed. If either one is
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non-zero, the section should be descrambled either in hardware or using the
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functions descramble_mac_address() and descramble_section_payload() of the
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demux API. Note that according to the MPEG-2 Systems specification, only
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the payloads of private sections can be scrambled while the rest of the section
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data must be sent in the clear.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int set(dmx_section_feed_t⋆ feed, __u16 pid, size_t
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circular_buffer_size, int descramble, int
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check_crc);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_section_feed_t*
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feed</para>
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</entry><entry
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align="char">
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<para>Pointer to the section feed API and instance data.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>__u16 pid</para>
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</entry><entry
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align="char">
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<para>PID value to filter; only the TS packets carrying the
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specified PID will be accepted.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>size_t
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circular_buffer_size</para>
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</entry><entry
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align="char">
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<para>Size of the circular buffer for filtered sections.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>int descramble</para>
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</entry><entry
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align="char">
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<para>If non-zero, descramble any sections that are scrambled.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>int check_crc</para>
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</entry><entry
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align="char">
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<para>If non-zero, check the CRC values of filtered sections.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-ENOMEM</para>
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</entry><entry
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align="char">
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<para>Not enough memory for the requested buffer size.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-ENOSYS</para>
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</entry><entry
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align="char">
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<para>No descrambling facility available for sections.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EINVAL</para>
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</entry><entry
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align="char">
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<para>Bad parameters.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section><section
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role="subsection"><title>allocate_filter()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This function is used to allocate a section filter on the demux. It should only be
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called when no filtering is in progress on this section feed. If a filter cannot be
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allocated, the function fails with -ENOSPC. See in section ?? for the format of
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the section filter.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>The bitfields filter_mask and filter_value should only be modified when no
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filtering is in progress on this section feed. filter_mask controls which bits of
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filter_value are compared with the section headers/payload. On a binary value
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of 1 in filter_mask, the corresponding bits are compared. The filter only accepts
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sections that are equal to filter_value in all the tested bit positions. Any changes
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to the values of filter_mask and filter_value are guaranteed to take effect only
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when the start_filtering() function is called next time. The parent pointer in
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the struct is initialized by the API implementation to the value of the feed
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parameter. The priv pointer is not used by the API implementation, and can
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thus be freely utilized by the caller of this function. Any data pointed to by the
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priv pointer is available to the recipient of the dmx_section_cb() function call.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>While the maximum section filter length (DMX_MAX_FILTER_SIZE) is
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currently set at 16 bytes, hardware filters of that size are not available on all
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platforms. Therefore, section filtering will often take place first in hardware,
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followed by filtering in software for the header bytes that were not covered
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by a hardware filter. The filter_mask field can be checked to determine how
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many bytes of the section filter are actually used, and if the hardware filter will
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suffice. Additionally, software-only section filters can optionally be allocated
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to clients when all hardware section filters are in use. Note that on most demux
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hardware it is not possible to filter on the section_length field of the section
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header – thus this field is ignored, even though it is included in filter_value and
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filter_mask fields.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int allocate_filter(dmx_section_feed_t⋆ feed,
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dmx_section_filter_t⋆⋆ filter);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_section_feed_t*
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feed</para>
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</entry><entry
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align="char">
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<para>Pointer to the section feed API and instance data.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>dmx_section_filter_t**
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filter</para>
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</entry><entry
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align="char">
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<para>Pointer to the allocated filter.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-ENOSPC</para>
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</entry><entry
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align="char">
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<para>No filters of given type and length available.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EINVAL</para>
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</entry><entry
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align="char">
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<para>Bad parameters.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section><section
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role="subsection"><title>release_filter()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>This function releases all the resources of a previously allocated section filter.
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The function should not be called while filtering is in progress on this section
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feed. After calling this function, the caller should not try to dereference the
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filter pointer.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int release_filter ( dmx_section_feed_t⋆ feed,
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dmx_section_filter_t⋆ filter);</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_section_feed_t*
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feed</para>
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</entry><entry
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align="char">
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<para>Pointer to the section feed API and instance data.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>dmx_section_filter_t*
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filter</para>
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</entry><entry
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align="char">
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<para>I/O Pointer to the instance data of a section filter.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-ENODEV</para>
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</entry><entry
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align="char">
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<para>No such filter allocated.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EINVAL</para>
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</entry><entry
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align="char">
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<para>Bad parameter.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section><section
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role="subsection"><title>start_filtering()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>Starts filtering sections on this section feed, according to its settings. Sections
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are first filtered based on their PID and then matched with the section
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filters allocated for this feed. If the section matches the PID filter and
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at least one section filter, it is delivered to the API client. The section
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is delivered asynchronously using the callback function registered with
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allocate_section_feed().</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int start_filtering ( dmx_section_feed_t⋆ feed );</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>dmx_section_feed_t*
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feed</para>
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</entry><entry
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align="char">
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<para>Pointer to the section feed API and instance data.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EINVAL</para>
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</entry><entry
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align="char">
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<para>Bad parameter.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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|
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</section><section
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role="subsection"><title>stop_filtering()</title>
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<para>DESCRIPTION
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>Stops filtering sections on this section feed. Note that any changes to the
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filtering parameters (filter_value, filter_mask, etc.) should only be made when
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filtering is stopped.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>SYNOPSIS
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</para>
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<informaltable><tgroup cols="1"><tbody><row><entry
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align="char">
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<para>int stop_filtering ( dmx_section_feed_t⋆ feed );</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>PARAMETERS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
|
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align="char">
|
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<para>dmx_section_feed_t*
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feed</para>
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</entry><entry
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align="char">
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<para>Pointer to the section feed API and instance data.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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<para>RETURNS
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</para>
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<informaltable><tgroup cols="2"><tbody><row><entry
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align="char">
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<para>0</para>
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</entry><entry
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align="char">
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<para>The function was completed without errors.</para>
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</entry>
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</row><row><entry
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align="char">
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<para>-EINVAL</para>
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</entry><entry
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align="char">
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<para>Bad parameter.</para>
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</entry>
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</row></tbody></tgroup></informaltable>
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</section>
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