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616 lines
24 KiB
ReStructuredText
616 lines
24 KiB
ReStructuredText
i.MX Video Capture Driver
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=========================
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Introduction
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------------
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The Freescale i.MX5/6 contains an Image Processing Unit (IPU), which
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handles the flow of image frames to and from capture devices and
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display devices.
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For image capture, the IPU contains the following internal subunits:
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- Image DMA Controller (IDMAC)
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- Camera Serial Interface (CSI)
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- Image Converter (IC)
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- Sensor Multi-FIFO Controller (SMFC)
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- Image Rotator (IRT)
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- Video De-Interlacing or Combining Block (VDIC)
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The IDMAC is the DMA controller for transfer of image frames to and from
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memory. Various dedicated DMA channels exist for both video capture and
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display paths. During transfer, the IDMAC is also capable of vertical
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image flip, 8x8 block transfer (see IRT description), pixel component
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re-ordering (for example UYVY to YUYV) within the same colorspace, and
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even packed <--> planar conversion. It can also perform a simple
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de-interlacing by interleaving even and odd lines during transfer
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(without motion compensation which requires the VDIC).
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The CSI is the backend capture unit that interfaces directly with
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camera sensors over Parallel, BT.656/1120, and MIPI CSI-2 busses.
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The IC handles color-space conversion, resizing (downscaling and
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upscaling), horizontal flip, and 90/270 degree rotation operations.
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There are three independent "tasks" within the IC that can carry out
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conversions concurrently: pre-process encoding, pre-process viewfinder,
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and post-processing. Within each task, conversions are split into three
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sections: downsizing section, main section (upsizing, flip, colorspace
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conversion, and graphics plane combining), and rotation section.
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The IPU time-shares the IC task operations. The time-slice granularity
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is one burst of eight pixels in the downsizing section, one image line
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in the main processing section, one image frame in the rotation section.
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The SMFC is composed of four independent FIFOs that each can transfer
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captured frames from sensors directly to memory concurrently via four
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IDMAC channels.
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The IRT carries out 90 and 270 degree image rotation operations. The
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rotation operation is carried out on 8x8 pixel blocks at a time. This
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operation is supported by the IDMAC which handles the 8x8 block transfer
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along with block reordering, in coordination with vertical flip.
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The VDIC handles the conversion of interlaced video to progressive, with
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support for different motion compensation modes (low, medium, and high
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motion). The deinterlaced output frames from the VDIC can be sent to the
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IC pre-process viewfinder task for further conversions. The VDIC also
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contains a Combiner that combines two image planes, with alpha blending
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and color keying.
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In addition to the IPU internal subunits, there are also two units
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outside the IPU that are also involved in video capture on i.MX:
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- MIPI CSI-2 Receiver for camera sensors with the MIPI CSI-2 bus
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interface. This is a Synopsys DesignWare core.
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- Two video multiplexers for selecting among multiple sensor inputs
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to send to a CSI.
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For more info, refer to the latest versions of the i.MX5/6 reference
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manuals [#f1]_ and [#f2]_.
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Features
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--------
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Some of the features of this driver include:
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- Many different pipelines can be configured via media controller API,
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that correspond to the hardware video capture pipelines supported in
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the i.MX.
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- Supports parallel, BT.565, and MIPI CSI-2 interfaces.
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- Concurrent independent streams, by configuring pipelines to multiple
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video capture interfaces using independent entities.
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- Scaling, color-space conversion, horizontal and vertical flip, and
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image rotation via IC task subdevs.
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- Many pixel formats supported (RGB, packed and planar YUV, partial
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planar YUV).
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- The VDIC subdev supports motion compensated de-interlacing, with three
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motion compensation modes: low, medium, and high motion. Pipelines are
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defined that allow sending frames to the VDIC subdev directly from the
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CSI. There is also support in the future for sending frames to the
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VDIC from memory buffers via a output/mem2mem devices.
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- Includes a Frame Interval Monitor (FIM) that can correct vertical sync
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problems with the ADV718x video decoders.
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Entities
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--------
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imx6-mipi-csi2
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--------------
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This is the MIPI CSI-2 receiver entity. It has one sink pad to receive
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the MIPI CSI-2 stream (usually from a MIPI CSI-2 camera sensor). It has
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four source pads, corresponding to the four MIPI CSI-2 demuxed virtual
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channel outputs. Multpiple source pads can be enabled to independently
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stream from multiple virtual channels.
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This entity actually consists of two sub-blocks. One is the MIPI CSI-2
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core. This is a Synopsys Designware MIPI CSI-2 core. The other sub-block
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is a "CSI-2 to IPU gasket". The gasket acts as a demultiplexer of the
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four virtual channels streams, providing four separate parallel buses
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containing each virtual channel that are routed to CSIs or video
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multiplexers as described below.
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On i.MX6 solo/dual-lite, all four virtual channel buses are routed to
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two video multiplexers. Both CSI0 and CSI1 can receive any virtual
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channel, as selected by the video multiplexers.
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On i.MX6 Quad, virtual channel 0 is routed to IPU1-CSI0 (after selected
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by a video mux), virtual channels 1 and 2 are hard-wired to IPU1-CSI1
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and IPU2-CSI0, respectively, and virtual channel 3 is routed to
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IPU2-CSI1 (again selected by a video mux).
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ipuX_csiY_mux
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-------------
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These are the video multiplexers. They have two or more sink pads to
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select from either camera sensors with a parallel interface, or from
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MIPI CSI-2 virtual channels from imx6-mipi-csi2 entity. They have a
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single source pad that routes to a CSI (ipuX_csiY entities).
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On i.MX6 solo/dual-lite, there are two video mux entities. One sits
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in front of IPU1-CSI0 to select between a parallel sensor and any of
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the four MIPI CSI-2 virtual channels (a total of five sink pads). The
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other mux sits in front of IPU1-CSI1, and again has five sink pads to
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select between a parallel sensor and any of the four MIPI CSI-2 virtual
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channels.
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On i.MX6 Quad, there are two video mux entities. One sits in front of
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IPU1-CSI0 to select between a parallel sensor and MIPI CSI-2 virtual
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channel 0 (two sink pads). The other mux sits in front of IPU2-CSI1 to
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select between a parallel sensor and MIPI CSI-2 virtual channel 3 (two
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sink pads).
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ipuX_csiY
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---------
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These are the CSI entities. They have a single sink pad receiving from
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either a video mux or from a MIPI CSI-2 virtual channel as described
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above.
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This entity has two source pads. The first source pad can link directly
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to the ipuX_vdic entity or the ipuX_ic_prp entity, using hardware links
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that require no IDMAC memory buffer transfer.
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When the direct source pad is routed to the ipuX_ic_prp entity, frames
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from the CSI can be processed by one or both of the IC pre-processing
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tasks.
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When the direct source pad is routed to the ipuX_vdic entity, the VDIC
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will carry out motion-compensated de-interlace using "high motion" mode
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(see description of ipuX_vdic entity).
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The second source pad sends video frames directly to memory buffers
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via the SMFC and an IDMAC channel, bypassing IC pre-processing. This
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source pad is routed to a capture device node, with a node name of the
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format "ipuX_csiY capture".
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Note that since the IDMAC source pad makes use of an IDMAC channel, it
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can do pixel reordering within the same colorspace. For example, the
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sink pad can take UYVY2X8, but the IDMAC source pad can output YUYV2X8.
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If the sink pad is receiving YUV, the output at the capture device can
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also be converted to a planar YUV format such as YUV420.
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It will also perform simple de-interlace without motion compensation,
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which is activated if the sink pad's field type is an interlaced type,
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and the IDMAC source pad field type is set to none.
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This subdev can generate the following event when enabling the second
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IDMAC source pad:
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- V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR
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The user application can subscribe to this event from the ipuX_csiY
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subdev node. This event is generated by the Frame Interval Monitor
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(see below for more on the FIM).
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Cropping in ipuX_csiY
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---------------------
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The CSI supports cropping the incoming raw sensor frames. This is
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implemented in the ipuX_csiY entities at the sink pad, using the
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crop selection subdev API.
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The CSI also supports fixed divide-by-two downscaling indepently in
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width and height. This is implemented in the ipuX_csiY entities at
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the sink pad, using the compose selection subdev API.
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The output rectangle at the ipuX_csiY source pad is the same as
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the compose rectangle at the sink pad. So the source pad rectangle
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cannot be negotiated, it must be set using the compose selection
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API at sink pad (if /2 downscale is desired, otherwise source pad
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rectangle is equal to incoming rectangle).
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To give an example of crop and /2 downscale, this will crop a
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1280x960 input frame to 640x480, and then /2 downscale in both
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dimensions to 320x240 (assumes ipu1_csi0 is linked to ipu1_csi0_mux):
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media-ctl -V "'ipu1_csi0_mux':2[fmt:UYVY2X8/1280x960]"
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media-ctl -V "'ipu1_csi0':0[crop:(0,0)/640x480]"
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media-ctl -V "'ipu1_csi0':0[compose:(0,0)/320x240]"
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Frame Skipping in ipuX_csiY
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---------------------------
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The CSI supports frame rate decimation, via frame skipping. Frame
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rate decimation is specified by setting the frame intervals at
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sink and source pads. The ipuX_csiY entity then applies the best
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frame skip setting to the CSI to achieve the desired frame rate
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at the source pad.
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The following example reduces an assumed incoming 60 Hz frame
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rate by half at the IDMAC output source pad:
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media-ctl -V "'ipu1_csi0':0[fmt:UYVY2X8/640x480@1/60]"
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media-ctl -V "'ipu1_csi0':2[fmt:UYVY2X8/640x480@1/30]"
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Frame Interval Monitor in ipuX_csiY
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-----------------------------------
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The adv718x decoders can occasionally send corrupt fields during
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NTSC/PAL signal re-sync (too little or too many video lines). When
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this happens, the IPU triggers a mechanism to re-establish vertical
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sync by adding 1 dummy line every frame, which causes a rolling effect
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from image to image, and can last a long time before a stable image is
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recovered. Or sometimes the mechanism doesn't work at all, causing a
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permanent split image (one frame contains lines from two consecutive
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captured images).
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From experiment it was found that during image rolling, the frame
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intervals (elapsed time between two EOF's) drop below the nominal
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value for the current standard, by about one frame time (60 usec),
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and remain at that value until rolling stops.
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While the reason for this observation isn't known (the IPU dummy
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line mechanism should show an increase in the intervals by 1 line
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time every frame, not a fixed value), we can use it to detect the
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corrupt fields using a frame interval monitor. If the FIM detects a
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bad frame interval, the ipuX_csiY subdev will send the event
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V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR. Userland can register with
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the FIM event notification on the ipuX_csiY subdev device node.
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Userland can issue a streaming restart when this event is received
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to correct the rolling/split image.
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The ipuX_csiY subdev includes custom controls to tweak some dials for
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FIM. If one of these controls is changed during streaming, the FIM will
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be reset and will continue at the new settings.
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- V4L2_CID_IMX_FIM_ENABLE
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Enable/disable the FIM.
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- V4L2_CID_IMX_FIM_NUM
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How many frame interval measurements to average before comparing against
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the nominal frame interval reported by the sensor. This can reduce noise
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caused by interrupt latency.
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- V4L2_CID_IMX_FIM_TOLERANCE_MIN
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If the averaged intervals fall outside nominal by this amount, in
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microseconds, the V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR event is sent.
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- V4L2_CID_IMX_FIM_TOLERANCE_MAX
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If any intervals are higher than this value, those samples are
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discarded and do not enter into the average. This can be used to
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discard really high interval errors that might be due to interrupt
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latency from high system load.
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- V4L2_CID_IMX_FIM_NUM_SKIP
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How many frames to skip after a FIM reset or stream restart before
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FIM begins to average intervals.
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- V4L2_CID_IMX_FIM_ICAP_CHANNEL
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- V4L2_CID_IMX_FIM_ICAP_EDGE
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These controls will configure an input capture channel as the method
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for measuring frame intervals. This is superior to the default method
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of measuring frame intervals via EOF interrupt, since it is not subject
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to uncertainty errors introduced by interrupt latency.
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Input capture requires hardware support. A VSYNC signal must be routed
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to one of the i.MX6 input capture channel pads.
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V4L2_CID_IMX_FIM_ICAP_CHANNEL configures which i.MX6 input capture
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channel to use. This must be 0 or 1.
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V4L2_CID_IMX_FIM_ICAP_EDGE configures which signal edge will trigger
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input capture events. By default the input capture method is disabled
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with a value of IRQ_TYPE_NONE. Set this control to IRQ_TYPE_EDGE_RISING,
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IRQ_TYPE_EDGE_FALLING, or IRQ_TYPE_EDGE_BOTH to enable input capture,
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triggered on the given signal edge(s).
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When input capture is disabled, frame intervals will be measured via
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EOF interrupt.
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ipuX_vdic
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---------
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The VDIC carries out motion compensated de-interlacing, with three
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motion compensation modes: low, medium, and high motion. The mode is
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specified with the menu control V4L2_CID_DEINTERLACING_MODE. It has
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two sink pads and a single source pad.
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The direct sink pad receives from an ipuX_csiY direct pad. With this
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link the VDIC can only operate in high motion mode.
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When the IDMAC sink pad is activated, it receives from an output
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or mem2mem device node. With this pipeline, it can also operate
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in low and medium modes, because these modes require receiving
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frames from memory buffers. Note that an output or mem2mem device
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is not implemented yet, so this sink pad currently has no links.
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The source pad routes to the IC pre-processing entity ipuX_ic_prp.
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ipuX_ic_prp
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-----------
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This is the IC pre-processing entity. It acts as a router, routing
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data from its sink pad to one or both of its source pads.
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It has a single sink pad. The sink pad can receive from the ipuX_csiY
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direct pad, or from ipuX_vdic.
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This entity has two source pads. One source pad routes to the
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pre-process encode task entity (ipuX_ic_prpenc), the other to the
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pre-process viewfinder task entity (ipuX_ic_prpvf). Both source pads
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can be activated at the same time if the sink pad is receiving from
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ipuX_csiY. Only the source pad to the pre-process viewfinder task entity
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can be activated if the sink pad is receiving from ipuX_vdic (frames
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from the VDIC can only be processed by the pre-process viewfinder task).
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ipuX_ic_prpenc
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--------------
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This is the IC pre-processing encode entity. It has a single sink
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pad from ipuX_ic_prp, and a single source pad. The source pad is
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routed to a capture device node, with a node name of the format
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"ipuX_ic_prpenc capture".
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This entity performs the IC pre-process encode task operations:
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color-space conversion, resizing (downscaling and upscaling),
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horizontal and vertical flip, and 90/270 degree rotation. Flip
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and rotation are provided via standard V4L2 controls.
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Like the ipuX_csiY IDMAC source, it can also perform simple de-interlace
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without motion compensation, and pixel reordering.
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ipuX_ic_prpvf
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-------------
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This is the IC pre-processing viewfinder entity. It has a single sink
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pad from ipuX_ic_prp, and a single source pad. The source pad is routed
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to a capture device node, with a node name of the format
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"ipuX_ic_prpvf capture".
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It is identical in operation to ipuX_ic_prpenc, with the same resizing
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and CSC operations and flip/rotation controls. It will receive and
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process de-interlaced frames from the ipuX_vdic if ipuX_ic_prp is
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receiving from ipuX_vdic.
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Like the ipuX_csiY IDMAC source, it can perform simple de-interlace
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without motion compensation. However, note that if the ipuX_vdic is
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included in the pipeline (ipuX_ic_prp is receiving from ipuX_vdic),
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it's not possible to use simple de-interlace in ipuX_ic_prpvf, since
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the ipuX_vdic has already carried out de-interlacing (with motion
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compensation) and therefore the field type output from ipuX_ic_prp can
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only be none.
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Capture Pipelines
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-----------------
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The following describe the various use-cases supported by the pipelines.
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The links shown do not include the backend sensor, video mux, or mipi
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csi-2 receiver links. This depends on the type of sensor interface
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(parallel or mipi csi-2). So these pipelines begin with:
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sensor -> ipuX_csiY_mux -> ...
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for parallel sensors, or:
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sensor -> imx6-mipi-csi2 -> (ipuX_csiY_mux) -> ...
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for mipi csi-2 sensors. The imx6-mipi-csi2 receiver may need to route
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to the video mux (ipuX_csiY_mux) before sending to the CSI, depending
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on the mipi csi-2 virtual channel, hence ipuX_csiY_mux is shown in
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parenthesis.
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Unprocessed Video Capture:
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--------------------------
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Send frames directly from sensor to camera device interface node, with
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no conversions, via ipuX_csiY IDMAC source pad:
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-> ipuX_csiY:2 -> ipuX_csiY capture
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IC Direct Conversions:
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----------------------
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This pipeline uses the preprocess encode entity to route frames directly
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from the CSI to the IC, to carry out scaling up to 1024x1024 resolution,
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CSC, flipping, and image rotation:
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-> ipuX_csiY:1 -> 0:ipuX_ic_prp:1 -> 0:ipuX_ic_prpenc:1 ->
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ipuX_ic_prpenc capture
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Motion Compensated De-interlace:
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--------------------------------
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This pipeline routes frames from the CSI direct pad to the VDIC entity to
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support motion-compensated de-interlacing (high motion mode only),
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scaling up to 1024x1024, CSC, flip, and rotation:
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-> ipuX_csiY:1 -> 0:ipuX_vdic:2 -> 0:ipuX_ic_prp:2 ->
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0:ipuX_ic_prpvf:1 -> ipuX_ic_prpvf capture
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Usage Notes
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-----------
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To aid in configuration and for backward compatibility with V4L2
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applications that access controls only from video device nodes, the
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capture device interfaces inherit controls from the active entities
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in the current pipeline, so controls can be accessed either directly
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from the subdev or from the active capture device interface. For
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example, the FIM controls are available either from the ipuX_csiY
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subdevs or from the active capture device.
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The following are specific usage notes for the Sabre* reference
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boards:
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SabreLite with OV5642 and OV5640
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--------------------------------
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This platform requires the OmniVision OV5642 module with a parallel
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camera interface, and the OV5640 module with a MIPI CSI-2
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interface. Both modules are available from Boundary Devices:
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https://boundarydevices.com/product/nit6x_5mp
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https://boundarydevices.com/product/nit6x_5mp_mipi
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Note that if only one camera module is available, the other sensor
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node can be disabled in the device tree.
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The OV5642 module is connected to the parallel bus input on the i.MX
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internal video mux to IPU1 CSI0. It's i2c bus connects to i2c bus 2.
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The MIPI CSI-2 OV5640 module is connected to the i.MX internal MIPI CSI-2
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receiver, and the four virtual channel outputs from the receiver are
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routed as follows: vc0 to the IPU1 CSI0 mux, vc1 directly to IPU1 CSI1,
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vc2 directly to IPU2 CSI0, and vc3 to the IPU2 CSI1 mux. The OV5640 is
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|
also connected to i2c bus 2 on the SabreLite, therefore the OV5642 and
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OV5640 must not share the same i2c slave address.
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|
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The following basic example configures unprocessed video capture
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pipelines for both sensors. The OV5642 is routed to ipu1_csi0, and
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the OV5640, transmitting on MIPI CSI-2 virtual channel 1 (which is
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imx6-mipi-csi2 pad 2), is routed to ipu1_csi1. Both sensors are
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configured to output 640x480, and the OV5642 outputs YUYV2X8, the
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OV5640 UYVY2X8:
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.. code-block:: none
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# Setup links for OV5642
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media-ctl -l "'ov5642 1-0042':0 -> 'ipu1_csi0_mux':1[1]"
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media-ctl -l "'ipu1_csi0_mux':2 -> 'ipu1_csi0':0[1]"
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media-ctl -l "'ipu1_csi0':2 -> 'ipu1_csi0 capture':0[1]"
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# Setup links for OV5640
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media-ctl -l "'ov5640 1-0040':0 -> 'imx6-mipi-csi2':0[1]"
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media-ctl -l "'imx6-mipi-csi2':2 -> 'ipu1_csi1':0[1]"
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media-ctl -l "'ipu1_csi1':2 -> 'ipu1_csi1 capture':0[1]"
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# Configure pads for OV5642 pipeline
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media-ctl -V "'ov5642 1-0042':0 [fmt:YUYV2X8/640x480 field:none]"
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media-ctl -V "'ipu1_csi0_mux':2 [fmt:YUYV2X8/640x480 field:none]"
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media-ctl -V "'ipu1_csi0':2 [fmt:AYUV32/640x480 field:none]"
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# Configure pads for OV5640 pipeline
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media-ctl -V "'ov5640 1-0040':0 [fmt:UYVY2X8/640x480 field:none]"
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media-ctl -V "'imx6-mipi-csi2':2 [fmt:UYVY2X8/640x480 field:none]"
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media-ctl -V "'ipu1_csi1':2 [fmt:AYUV32/640x480 field:none]"
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Streaming can then begin independently on the capture device nodes
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"ipu1_csi0 capture" and "ipu1_csi1 capture". The v4l2-ctl tool can
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be used to select any supported YUV pixelformat on the capture device
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nodes, including planar.
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|
SabreAuto with ADV7180 decoder
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|
------------------------------
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On the SabreAuto, an on-board ADV7180 SD decoder is connected to the
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parallel bus input on the internal video mux to IPU1 CSI0.
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The following example configures a pipeline to capture from the ADV7180
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|
video decoder, assuming NTSC 720x480 input signals, with Motion
|
|
Compensated de-interlacing. Pad field types assume the adv7180 outputs
|
|
"interlaced". $outputfmt can be any format supported by the ipu1_ic_prpvf
|
|
entity at its output pad:
|
|
|
|
.. code-block:: none
|
|
|
|
# Setup links
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|
media-ctl -l "'adv7180 3-0021':0 -> 'ipu1_csi0_mux':1[1]"
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media-ctl -l "'ipu1_csi0_mux':2 -> 'ipu1_csi0':0[1]"
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media-ctl -l "'ipu1_csi0':1 -> 'ipu1_vdic':0[1]"
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media-ctl -l "'ipu1_vdic':2 -> 'ipu1_ic_prp':0[1]"
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|
media-ctl -l "'ipu1_ic_prp':2 -> 'ipu1_ic_prpvf':0[1]"
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|
media-ctl -l "'ipu1_ic_prpvf':1 -> 'ipu1_ic_prpvf capture':0[1]"
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# Configure pads
|
|
media-ctl -V "'adv7180 3-0021':0 [fmt:UYVY2X8/720x480]"
|
|
media-ctl -V "'ipu1_csi0_mux':2 [fmt:UYVY2X8/720x480 field:interlaced]"
|
|
media-ctl -V "'ipu1_csi0':1 [fmt:AYUV32/720x480 field:interlaced]"
|
|
media-ctl -V "'ipu1_vdic':2 [fmt:AYUV32/720x480 field:none]"
|
|
media-ctl -V "'ipu1_ic_prp':2 [fmt:AYUV32/720x480 field:none]"
|
|
media-ctl -V "'ipu1_ic_prpvf':1 [fmt:$outputfmt field:none]"
|
|
|
|
Streaming can then begin on the capture device node at
|
|
"ipu1_ic_prpvf capture". The v4l2-ctl tool can be used to select any
|
|
supported YUV or RGB pixelformat on the capture device node.
|
|
|
|
This platform accepts Composite Video analog inputs to the ADV7180 on
|
|
Ain1 (connector J42).
|
|
|
|
SabreSD with MIPI CSI-2 OV5640
|
|
------------------------------
|
|
|
|
Similarly to SabreLite, the SabreSD supports a parallel interface
|
|
OV5642 module on IPU1 CSI0, and a MIPI CSI-2 OV5640 module. The OV5642
|
|
connects to i2c bus 1 and the OV5640 to i2c bus 2.
|
|
|
|
The device tree for SabreSD includes OF graphs for both the parallel
|
|
OV5642 and the MIPI CSI-2 OV5640, but as of this writing only the MIPI
|
|
CSI-2 OV5640 has been tested, so the OV5642 node is currently disabled.
|
|
The OV5640 module connects to MIPI connector J5 (sorry I don't have the
|
|
compatible module part number or URL).
|
|
|
|
The following example configures a direct conversion pipeline to capture
|
|
from the OV5640, transmitting on MIPI CSI-2 virtual channel 1. $sensorfmt
|
|
can be any format supported by the OV5640. $sensordim is the frame
|
|
dimension part of $sensorfmt (minus the mbus pixel code). $outputfmt can
|
|
be any format supported by the ipu1_ic_prpenc entity at its output pad:
|
|
|
|
.. code-block:: none
|
|
|
|
# Setup links
|
|
media-ctl -l "'ov5640 1-003c':0 -> 'imx6-mipi-csi2':0[1]"
|
|
media-ctl -l "'imx6-mipi-csi2':2 -> 'ipu1_csi1':0[1]"
|
|
media-ctl -l "'ipu1_csi1':1 -> 'ipu1_ic_prp':0[1]"
|
|
media-ctl -l "'ipu1_ic_prp':1 -> 'ipu1_ic_prpenc':0[1]"
|
|
media-ctl -l "'ipu1_ic_prpenc':1 -> 'ipu1_ic_prpenc capture':0[1]"
|
|
# Configure pads
|
|
media-ctl -V "'ov5640 1-003c':0 [fmt:$sensorfmt field:none]"
|
|
media-ctl -V "'imx6-mipi-csi2':2 [fmt:$sensorfmt field:none]"
|
|
media-ctl -V "'ipu1_csi1':1 [fmt:AYUV32/$sensordim field:none]"
|
|
media-ctl -V "'ipu1_ic_prp':1 [fmt:AYUV32/$sensordim field:none]"
|
|
media-ctl -V "'ipu1_ic_prpenc':1 [fmt:$outputfmt field:none]"
|
|
|
|
Streaming can then begin on "ipu1_ic_prpenc capture" node. The v4l2-ctl
|
|
tool can be used to select any supported YUV or RGB pixelformat on the
|
|
capture device node.
|
|
|
|
|
|
Known Issues
|
|
------------
|
|
|
|
1. When using 90 or 270 degree rotation control at capture resolutions
|
|
near the IC resizer limit of 1024x1024, and combined with planar
|
|
pixel formats (YUV420, YUV422p), frame capture will often fail with
|
|
no end-of-frame interrupts from the IDMAC channel. To work around
|
|
this, use lower resolution and/or packed formats (YUYV, RGB3, etc.)
|
|
when 90 or 270 rotations are needed.
|
|
|
|
|
|
File list
|
|
---------
|
|
|
|
drivers/staging/media/imx/
|
|
include/media/imx.h
|
|
include/linux/imx-media.h
|
|
|
|
References
|
|
----------
|
|
|
|
.. [#f1] http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX6DQRM.pdf
|
|
.. [#f2] http://www.nxp.com/assets/documents/data/en/reference-manuals/IMX6SDLRM.pdf
|
|
|
|
|
|
Authors
|
|
-------
|
|
|
|
- Steve Longerbeam <steve_longerbeam@mentor.com>
|
|
- Philipp Zabel <kernel@pengutronix.de>
|
|
- Russell King <linux@armlinux.org.uk>
|
|
|
|
Copyright (C) 2012-2017 Mentor Graphics Inc.
|