331 lines
12 KiB
C++
331 lines
12 KiB
C++
/*
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* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "common_video/h264/h264_bitstream_parser.h"
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#include <stdlib.h>
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#include <cstdint>
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#include <vector>
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#include "common_video/h264/h264_common.h"
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#include "rtc_base/bit_buffer.h"
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#include "rtc_base/logging.h"
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namespace {
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const int kMaxAbsQpDeltaValue = 51;
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const int kMinQpValue = 0;
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const int kMaxQpValue = 51;
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} // namespace
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namespace webrtc {
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#define RETURN_ON_FAIL(x, res) \
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if (!(x)) { \
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RTC_LOG_F(LS_ERROR) << "FAILED: " #x; \
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return res; \
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}
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#define RETURN_INV_ON_FAIL(x) RETURN_ON_FAIL(x, kInvalidStream)
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H264BitstreamParser::H264BitstreamParser() {}
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H264BitstreamParser::~H264BitstreamParser() {}
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H264BitstreamParser::Result H264BitstreamParser::ParseNonParameterSetNalu(
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const uint8_t* source,
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size_t source_length,
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uint8_t nalu_type) {
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if (!sps_ || !pps_)
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return kInvalidStream;
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last_slice_qp_delta_ = absl::nullopt;
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const std::vector<uint8_t> slice_rbsp =
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H264::ParseRbsp(source, source_length);
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if (slice_rbsp.size() < H264::kNaluTypeSize)
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return kInvalidStream;
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rtc::BitBuffer slice_reader(slice_rbsp.data() + H264::kNaluTypeSize,
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slice_rbsp.size() - H264::kNaluTypeSize);
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// Check to see if this is an IDR slice, which has an extra field to parse
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// out.
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bool is_idr = (source[0] & 0x0F) == H264::NaluType::kIdr;
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uint8_t nal_ref_idc = (source[0] & 0x60) >> 5;
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uint32_t golomb_tmp;
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uint32_t bits_tmp;
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// first_mb_in_slice: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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// slice_type: ue(v)
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uint32_t slice_type;
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&slice_type));
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// slice_type's 5..9 range is used to indicate that all slices of a picture
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// have the same value of slice_type % 5, we don't care about that, so we map
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// to the corresponding 0..4 range.
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slice_type %= 5;
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// pic_parameter_set_id: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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if (sps_->separate_colour_plane_flag == 1) {
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// colour_plane_id
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RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
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}
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// frame_num: u(v)
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// Represented by log2_max_frame_num bits.
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&bits_tmp, sps_->log2_max_frame_num));
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uint32_t field_pic_flag = 0;
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if (sps_->frame_mbs_only_flag == 0) {
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// field_pic_flag: u(1)
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RETURN_INV_ON_FAIL(slice_reader.ReadBits(&field_pic_flag, 1));
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if (field_pic_flag != 0) {
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// bottom_field_flag: u(1)
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RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
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}
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}
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if (is_idr) {
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// idr_pic_id: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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// pic_order_cnt_lsb: u(v)
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// Represented by sps_.log2_max_pic_order_cnt_lsb bits.
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if (sps_->pic_order_cnt_type == 0) {
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&bits_tmp, sps_->log2_max_pic_order_cnt_lsb));
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if (pps_->bottom_field_pic_order_in_frame_present_flag &&
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field_pic_flag == 0) {
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// delta_pic_order_cnt_bottom: se(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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}
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if (sps_->pic_order_cnt_type == 1 &&
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!sps_->delta_pic_order_always_zero_flag) {
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// delta_pic_order_cnt[0]: se(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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if (pps_->bottom_field_pic_order_in_frame_present_flag && !field_pic_flag) {
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// delta_pic_order_cnt[1]: se(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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}
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if (pps_->redundant_pic_cnt_present_flag) {
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// redundant_pic_cnt: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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if (slice_type == H264::SliceType::kB) {
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// direct_spatial_mv_pred_flag: u(1)
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RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
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}
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switch (slice_type) {
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case H264::SliceType::kP:
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case H264::SliceType::kB:
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case H264::SliceType::kSp:
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uint32_t num_ref_idx_active_override_flag;
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// num_ref_idx_active_override_flag: u(1)
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&num_ref_idx_active_override_flag, 1));
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if (num_ref_idx_active_override_flag != 0) {
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// num_ref_idx_l0_active_minus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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if (slice_type == H264::SliceType::kB) {
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// num_ref_idx_l1_active_minus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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}
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break;
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default:
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break;
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}
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// assume nal_unit_type != 20 && nal_unit_type != 21:
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if (nalu_type == 20 || nalu_type == 21) {
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RTC_LOG(LS_ERROR) << "Unsupported nal unit type.";
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return kUnsupportedStream;
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}
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// if (nal_unit_type == 20 || nal_unit_type == 21)
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// ref_pic_list_mvc_modification()
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// else
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{
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// ref_pic_list_modification():
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// |slice_type| checks here don't use named constants as they aren't named
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// in the spec for this segment. Keeping them consistent makes it easier to
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// verify that they are both the same.
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if (slice_type % 5 != 2 && slice_type % 5 != 4) {
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// ref_pic_list_modification_flag_l0: u(1)
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uint32_t ref_pic_list_modification_flag_l0;
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&ref_pic_list_modification_flag_l0, 1));
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if (ref_pic_list_modification_flag_l0) {
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uint32_t modification_of_pic_nums_idc;
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do {
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// modification_of_pic_nums_idc: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
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&modification_of_pic_nums_idc));
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if (modification_of_pic_nums_idc == 0 ||
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modification_of_pic_nums_idc == 1) {
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// abs_diff_pic_num_minus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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} else if (modification_of_pic_nums_idc == 2) {
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// long_term_pic_num: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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} while (modification_of_pic_nums_idc != 3);
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}
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}
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if (slice_type % 5 == 1) {
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// ref_pic_list_modification_flag_l1: u(1)
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uint32_t ref_pic_list_modification_flag_l1;
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&ref_pic_list_modification_flag_l1, 1));
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if (ref_pic_list_modification_flag_l1) {
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uint32_t modification_of_pic_nums_idc;
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do {
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// modification_of_pic_nums_idc: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
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&modification_of_pic_nums_idc));
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if (modification_of_pic_nums_idc == 0 ||
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modification_of_pic_nums_idc == 1) {
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// abs_diff_pic_num_minus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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} else if (modification_of_pic_nums_idc == 2) {
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// long_term_pic_num: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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} while (modification_of_pic_nums_idc != 3);
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}
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}
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}
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// TODO(pbos): Do we need support for pred_weight_table()?
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if ((pps_->weighted_pred_flag && (slice_type == H264::SliceType::kP ||
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slice_type == H264::SliceType::kSp)) ||
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(pps_->weighted_bipred_idc == 1 && slice_type == H264::SliceType::kB)) {
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RTC_LOG(LS_ERROR) << "Streams with pred_weight_table unsupported.";
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return kUnsupportedStream;
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}
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// if ((weighted_pred_flag && (slice_type == P || slice_type == SP)) ||
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// (weighted_bipred_idc == 1 && slice_type == B)) {
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// pred_weight_table()
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// }
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if (nal_ref_idc != 0) {
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// dec_ref_pic_marking():
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if (is_idr) {
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// no_output_of_prior_pics_flag: u(1)
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// long_term_reference_flag: u(1)
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RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
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} else {
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// adaptive_ref_pic_marking_mode_flag: u(1)
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uint32_t adaptive_ref_pic_marking_mode_flag;
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RETURN_INV_ON_FAIL(
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slice_reader.ReadBits(&adaptive_ref_pic_marking_mode_flag, 1));
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if (adaptive_ref_pic_marking_mode_flag) {
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uint32_t memory_management_control_operation;
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do {
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// memory_management_control_operation: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
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&memory_management_control_operation));
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if (memory_management_control_operation == 1 ||
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memory_management_control_operation == 3) {
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// difference_of_pic_nums_minus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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if (memory_management_control_operation == 2) {
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// long_term_pic_num: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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if (memory_management_control_operation == 3 ||
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memory_management_control_operation == 6) {
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// long_term_frame_idx: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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if (memory_management_control_operation == 4) {
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// max_long_term_frame_idx_plus1: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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} while (memory_management_control_operation != 0);
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}
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}
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}
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if (pps_->entropy_coding_mode_flag && slice_type != H264::SliceType::kI &&
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slice_type != H264::SliceType::kSi) {
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// cabac_init_idc: ue(v)
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RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
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}
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int32_t last_slice_qp_delta;
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RETURN_INV_ON_FAIL(
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slice_reader.ReadSignedExponentialGolomb(&last_slice_qp_delta));
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if (abs(last_slice_qp_delta) > kMaxAbsQpDeltaValue) {
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// Something has gone wrong, and the parsed value is invalid.
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RTC_LOG(LS_WARNING) << "Parsed QP value out of range.";
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return kInvalidStream;
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}
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last_slice_qp_delta_ = last_slice_qp_delta;
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return kOk;
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}
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void H264BitstreamParser::ParseSlice(const uint8_t* slice, size_t length) {
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H264::NaluType nalu_type = H264::ParseNaluType(slice[0]);
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switch (nalu_type) {
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case H264::NaluType::kSps: {
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sps_ = SpsParser::ParseSps(slice + H264::kNaluTypeSize,
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length - H264::kNaluTypeSize);
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if (!sps_)
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RTC_LOG(LS_WARNING) << "Unable to parse SPS from H264 bitstream.";
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break;
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}
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case H264::NaluType::kPps: {
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pps_ = PpsParser::ParsePps(slice + H264::kNaluTypeSize,
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length - H264::kNaluTypeSize);
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if (!pps_)
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RTC_LOG(LS_WARNING) << "Unable to parse PPS from H264 bitstream.";
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break;
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}
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case H264::NaluType::kAud:
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case H264::NaluType::kSei:
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break; // Ignore these nalus, as we don't care about their contents.
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default:
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Result res = ParseNonParameterSetNalu(slice, length, nalu_type);
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if (res != kOk)
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RTC_LOG(LS_INFO) << "Failed to parse bitstream. Error: " << res;
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break;
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}
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}
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void H264BitstreamParser::ParseBitstream(const uint8_t* bitstream,
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size_t length) {
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std::vector<H264::NaluIndex> nalu_indices =
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H264::FindNaluIndices(bitstream, length);
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for (const H264::NaluIndex& index : nalu_indices)
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ParseSlice(&bitstream[index.payload_start_offset], index.payload_size);
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}
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bool H264BitstreamParser::GetLastSliceQp(int* qp) const {
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if (!last_slice_qp_delta_ || !pps_)
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return false;
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const int parsed_qp = 26 + pps_->pic_init_qp_minus26 + *last_slice_qp_delta_;
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if (parsed_qp < kMinQpValue || parsed_qp > kMaxQpValue) {
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RTC_LOG(LS_ERROR) << "Parsed invalid QP from bitstream.";
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return false;
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}
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*qp = parsed_qp;
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return true;
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}
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void H264BitstreamParser::ParseBitstream(
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rtc::ArrayView<const uint8_t> bitstream) {
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ParseBitstream(bitstream.data(), bitstream.size());
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}
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absl::optional<int> H264BitstreamParser::GetLastSliceQp() const {
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int qp;
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bool success = GetLastSliceQp(&qp);
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return success ? absl::optional<int>(qp) : absl::nullopt;
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}
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} // namespace webrtc
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