blob: 439beecec29313437fb4dfc200afad3b76cafc4d [file] [log] [blame]
/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "common_video/h264/h264_bitstream_parser.h"
#include <memory>
#include <vector>
#include "rtc_base/bitbuffer.h"
#include "rtc_base/checks.h"
#include "common_video/h264/h264_common.h"
#include "rtc_base/logging.h"
namespace {
const int kMaxAbsQpDeltaValue = 51;
const int kMinQpValue = 0;
const int kMaxQpValue = 51;
}
namespace webrtc {
#define RETURN_ON_FAIL(x, res) \
if (!(x)) { \
RTC_LOG_F(LS_ERROR) << "FAILED: " #x; \
return res; \
}
#define RETURN_INV_ON_FAIL(x) RETURN_ON_FAIL(x, kInvalidStream)
H264BitstreamParser::H264BitstreamParser() {}
H264BitstreamParser::~H264BitstreamParser() {}
H264BitstreamParser::Result H264BitstreamParser::ParseNonParameterSetNalu(
const uint8_t* source,
size_t source_length,
uint8_t nalu_type) {
if (!sps_ || !pps_)
return kInvalidStream;
last_slice_qp_delta_ = rtc::nullopt;
const std::vector<uint8_t> slice_rbsp =
H264::ParseRbsp(source, source_length);
if (slice_rbsp.size() < H264::kNaluTypeSize)
return kInvalidStream;
rtc::BitBuffer slice_reader(slice_rbsp.data() + H264::kNaluTypeSize,
slice_rbsp.size() - H264::kNaluTypeSize);
// Check to see if this is an IDR slice, which has an extra field to parse
// out.
bool is_idr = (source[0] & 0x0F) == H264::NaluType::kIdr;
uint8_t nal_ref_idc = (source[0] & 0x60) >> 5;
uint32_t golomb_tmp;
uint32_t bits_tmp;
// first_mb_in_slice: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
// slice_type: ue(v)
uint32_t slice_type;
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&slice_type));
// slice_type's 5..9 range is used to indicate that all slices of a picture
// have the same value of slice_type % 5, we don't care about that, so we map
// to the corresponding 0..4 range.
slice_type %= 5;
// pic_parameter_set_id: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
if (sps_->separate_colour_plane_flag == 1) {
// colour_plane_id
RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
}
// frame_num: u(v)
// Represented by log2_max_frame_num_minus4 + 4 bits.
RETURN_INV_ON_FAIL(
slice_reader.ReadBits(&bits_tmp, sps_->log2_max_frame_num_minus4 + 4));
uint32_t field_pic_flag = 0;
if (sps_->frame_mbs_only_flag == 0) {
// field_pic_flag: u(1)
RETURN_INV_ON_FAIL(slice_reader.ReadBits(&field_pic_flag, 1));
if (field_pic_flag != 0) {
// bottom_field_flag: u(1)
RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
}
}
if (is_idr) {
// idr_pic_id: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
// pic_order_cnt_lsb: u(v)
// Represented by sps_.log2_max_pic_order_cnt_lsb_minus4 + 4 bits.
if (sps_->pic_order_cnt_type == 0) {
RETURN_INV_ON_FAIL(slice_reader.ReadBits(
&bits_tmp, sps_->log2_max_pic_order_cnt_lsb_minus4 + 4));
if (pps_->bottom_field_pic_order_in_frame_present_flag &&
field_pic_flag == 0) {
// delta_pic_order_cnt_bottom: se(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
}
if (sps_->pic_order_cnt_type == 1 &&
!sps_->delta_pic_order_always_zero_flag) {
// delta_pic_order_cnt[0]: se(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
if (pps_->bottom_field_pic_order_in_frame_present_flag && !field_pic_flag) {
// delta_pic_order_cnt[1]: se(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
}
if (pps_->redundant_pic_cnt_present_flag) {
// redundant_pic_cnt: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
if (slice_type == H264::SliceType::kB) {
// direct_spatial_mv_pred_flag: u(1)
RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 1));
}
switch (slice_type) {
case H264::SliceType::kP:
case H264::SliceType::kB:
case H264::SliceType::kSp:
uint32_t num_ref_idx_active_override_flag;
// num_ref_idx_active_override_flag: u(1)
RETURN_INV_ON_FAIL(
slice_reader.ReadBits(&num_ref_idx_active_override_flag, 1));
if (num_ref_idx_active_override_flag != 0) {
// num_ref_idx_l0_active_minus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
if (slice_type == H264::SliceType::kB) {
// num_ref_idx_l1_active_minus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
}
break;
default:
break;
}
// assume nal_unit_type != 20 && nal_unit_type != 21:
if (nalu_type == 20 || nalu_type == 21) {
RTC_LOG(LS_ERROR) << "Unsupported nal unit type.";
return kUnsupportedStream;
}
// if (nal_unit_type == 20 || nal_unit_type == 21)
// ref_pic_list_mvc_modification()
// else
{
// ref_pic_list_modification():
// |slice_type| checks here don't use named constants as they aren't named
// in the spec for this segment. Keeping them consistent makes it easier to
// verify that they are both the same.
if (slice_type % 5 != 2 && slice_type % 5 != 4) {
// ref_pic_list_modification_flag_l0: u(1)
uint32_t ref_pic_list_modification_flag_l0;
RETURN_INV_ON_FAIL(
slice_reader.ReadBits(&ref_pic_list_modification_flag_l0, 1));
if (ref_pic_list_modification_flag_l0) {
uint32_t modification_of_pic_nums_idc;
do {
// modification_of_pic_nums_idc: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
&modification_of_pic_nums_idc));
if (modification_of_pic_nums_idc == 0 ||
modification_of_pic_nums_idc == 1) {
// abs_diff_pic_num_minus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
} else if (modification_of_pic_nums_idc == 2) {
// long_term_pic_num: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
} while (modification_of_pic_nums_idc != 3);
}
}
if (slice_type % 5 == 1) {
// ref_pic_list_modification_flag_l1: u(1)
uint32_t ref_pic_list_modification_flag_l1;
RETURN_INV_ON_FAIL(
slice_reader.ReadBits(&ref_pic_list_modification_flag_l1, 1));
if (ref_pic_list_modification_flag_l1) {
uint32_t modification_of_pic_nums_idc;
do {
// modification_of_pic_nums_idc: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
&modification_of_pic_nums_idc));
if (modification_of_pic_nums_idc == 0 ||
modification_of_pic_nums_idc == 1) {
// abs_diff_pic_num_minus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
} else if (modification_of_pic_nums_idc == 2) {
// long_term_pic_num: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
} while (modification_of_pic_nums_idc != 3);
}
}
}
// TODO(pbos): Do we need support for pred_weight_table()?
if ((pps_->weighted_pred_flag && (slice_type == H264::SliceType::kP ||
slice_type == H264::SliceType::kSp)) ||
(pps_->weighted_bipred_idc == 1 && slice_type == H264::SliceType::kB)) {
RTC_LOG(LS_ERROR) << "Streams with pred_weight_table unsupported.";
return kUnsupportedStream;
}
// if ((weighted_pred_flag && (slice_type == P || slice_type == SP)) ||
// (weighted_bipred_idc == 1 && slice_type == B)) {
// pred_weight_table()
// }
if (nal_ref_idc != 0) {
// dec_ref_pic_marking():
if (is_idr) {
// no_output_of_prior_pics_flag: u(1)
// long_term_reference_flag: u(1)
RETURN_INV_ON_FAIL(slice_reader.ReadBits(&bits_tmp, 2));
} else {
// adaptive_ref_pic_marking_mode_flag: u(1)
uint32_t adaptive_ref_pic_marking_mode_flag;
RETURN_INV_ON_FAIL(
slice_reader.ReadBits(&adaptive_ref_pic_marking_mode_flag, 1));
if (adaptive_ref_pic_marking_mode_flag) {
uint32_t memory_management_control_operation;
do {
// memory_management_control_operation: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(
&memory_management_control_operation));
if (memory_management_control_operation == 1 ||
memory_management_control_operation == 3) {
// difference_of_pic_nums_minus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
if (memory_management_control_operation == 2) {
// long_term_pic_num: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
if (memory_management_control_operation == 3 ||
memory_management_control_operation == 6) {
// long_term_frame_idx: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
if (memory_management_control_operation == 4) {
// max_long_term_frame_idx_plus1: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
} while (memory_management_control_operation != 0);
}
}
}
if (pps_->entropy_coding_mode_flag &&
slice_type != H264::SliceType::kI && slice_type != H264::SliceType::kSi) {
// cabac_init_idc: ue(v)
RETURN_INV_ON_FAIL(slice_reader.ReadExponentialGolomb(&golomb_tmp));
}
int32_t last_slice_qp_delta;
RETURN_INV_ON_FAIL(
slice_reader.ReadSignedExponentialGolomb(&last_slice_qp_delta));
if (abs(last_slice_qp_delta) > kMaxAbsQpDeltaValue) {
// Something has gone wrong, and the parsed value is invalid.
RTC_LOG(LS_WARNING) << "Parsed QP value out of range.";
return kInvalidStream;
}
last_slice_qp_delta_ = last_slice_qp_delta;
return kOk;
}
void H264BitstreamParser::ParseSlice(const uint8_t* slice, size_t length) {
H264::NaluType nalu_type = H264::ParseNaluType(slice[0]);
switch (nalu_type) {
case H264::NaluType::kSps: {
sps_ = SpsParser::ParseSps(slice + H264::kNaluTypeSize,
length - H264::kNaluTypeSize);
if (!sps_)
RTC_LOG(LS_WARNING) << "Unable to parse SPS from H264 bitstream.";
break;
}
case H264::NaluType::kPps: {
pps_ = PpsParser::ParsePps(slice + H264::kNaluTypeSize,
length - H264::kNaluTypeSize);
if (!pps_)
RTC_LOG(LS_WARNING) << "Unable to parse PPS from H264 bitstream.";
break;
}
case H264::NaluType::kAud:
case H264::NaluType::kSei:
break; // Ignore these nalus, as we don't care about their contents.
default:
Result res = ParseNonParameterSetNalu(slice, length, nalu_type);
if (res != kOk)
RTC_LOG(LS_INFO) << "Failed to parse bitstream. Error: " << res;
break;
}
}
void H264BitstreamParser::ParseBitstream(const uint8_t* bitstream,
size_t length) {
std::vector<H264::NaluIndex> nalu_indices =
H264::FindNaluIndices(bitstream, length);
for (const H264::NaluIndex& index : nalu_indices)
ParseSlice(&bitstream[index.payload_start_offset], index.payload_size);
}
bool H264BitstreamParser::GetLastSliceQp(int* qp) const {
if (!last_slice_qp_delta_ || !pps_)
return false;
const int parsed_qp = 26 + pps_->pic_init_qp_minus26 + *last_slice_qp_delta_;
if (parsed_qp < kMinQpValue || parsed_qp > kMaxQpValue) {
RTC_LOG(LS_ERROR) << "Parsed invalid QP from bitstream.";
return false;
}
*qp = parsed_qp;
return true;
}
} // namespace webrtc