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/*
* Copyright (c) 2023 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/h265/h265_bitstream_parser.h"
#include <stdlib.h>
#include <cstdint>
#include <limits>
#include <vector>
#include "common_video/h265/h265_common.h"
#include "rtc_base/bit_buffer.h"
#include "rtc_base/bitstream_reader.h"
#include "rtc_base/logging.h"
#define IN_RANGE_OR_RETURN(val, min, max) \
do { \
if (!slice_reader.Ok() || (val) < (min) || (val) > (max)) { \
RTC_LOG(LS_WARNING) << "Error in stream: invalid value, expected " #val \
" to be" \
<< " in range [" << (min) << ":" << (max) << "]" \
<< " found " << (val) << " instead"; \
return kInvalidStream; \
} \
} while (0)
#define IN_RANGE_OR_RETURN_NULL(val, min, max) \
do { \
if (!slice_reader.Ok() || (val) < (min) || (val) > (max)) { \
RTC_LOG(LS_WARNING) << "Error in stream: invalid value, expected " #val \
" to be" \
<< " in range [" << (min) << ":" << (max) << "]" \
<< " found " << (val) << " instead"; \
return std::nullopt; \
} \
} while (0)
#define IN_RANGE_OR_RETURN_VOID(val, min, max) \
do { \
if (!slice_reader.Ok() || (val) < (min) || (val) > (max)) { \
RTC_LOG(LS_WARNING) << "Error in stream: invalid value, expected " #val \
" to be" \
<< " in range [" << (min) << ":" << (max) << "]" \
<< " found " << (val) << " instead"; \
return; \
} \
} while (0)
#define TRUE_OR_RETURN(a) \
do { \
if (!slice_reader.Ok() || !(a)) { \
RTC_LOG(LS_WARNING) << "Error in stream: invalid value, expected " \
<< #a; \
return kInvalidStream; \
} \
} while (0)
namespace {
constexpr int kMaxAbsQpDeltaValue = 51;
constexpr int kMinQpValue = 0;
constexpr int kMaxQpValue = 51;
constexpr int kMaxRefIdxActive = 15;
} // namespace
namespace webrtc {
H265BitstreamParser::H265BitstreamParser() = default;
H265BitstreamParser::~H265BitstreamParser() = default;
// General note: this is based off the 08/2021 version of the H.265 standard,
// section 7.3.6.1. You can find it on this page:
H265BitstreamParser::Result H265BitstreamParser::ParseNonParameterSetNalu(
rtc::ArrayView<const uint8_t> source,
uint8_t nalu_type) {
last_slice_qp_delta_ = std::nullopt;
last_slice_pps_id_ = std::nullopt;
const std::vector<uint8_t> slice_rbsp = H265::ParseRbsp(source);
if (slice_rbsp.size() < H265::kNaluHeaderSize)
return kInvalidStream;
BitstreamReader slice_reader(slice_rbsp);
slice_reader.ConsumeBits(H265::kNaluHeaderSize * 8);
// first_slice_segment_in_pic_flag: u(1)
bool first_slice_segment_in_pic_flag = slice_reader.Read<bool>();
bool irap_pic = (H265::NaluType::kBlaWLp <= nalu_type &&
nalu_type <= H265::NaluType::kRsvIrapVcl23);
if (irap_pic) {
// no_output_of_prior_pics_flag: u(1)
slice_reader.ConsumeBits(1);
}
// slice_pic_parameter_set_id: ue(v)
uint32_t pps_id = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(pps_id, 0, 63);
const H265PpsParser::PpsState* pps = GetPPS(pps_id);
TRUE_OR_RETURN(pps);
const H265SpsParser::SpsState* sps = GetSPS(pps->sps_id);
TRUE_OR_RETURN(sps);
bool dependent_slice_segment_flag = 0;
if (!first_slice_segment_in_pic_flag) {
if (pps->dependent_slice_segments_enabled_flag) {
// dependent_slice_segment_flag: u(1)
dependent_slice_segment_flag = slice_reader.Read<bool>();
}
// slice_segment_address: u(v)
int32_t log2_ctb_size_y = sps->log2_min_luma_coding_block_size_minus3 + 3 +
sps->log2_diff_max_min_luma_coding_block_size;
uint32_t ctb_size_y = 1 << log2_ctb_size_y;
uint32_t pic_width_in_ctbs_y = sps->pic_width_in_luma_samples / ctb_size_y;
if (sps->pic_width_in_luma_samples % ctb_size_y)
pic_width_in_ctbs_y++;
uint32_t pic_height_in_ctbs_y =
sps->pic_height_in_luma_samples / ctb_size_y;
if (sps->pic_height_in_luma_samples % ctb_size_y)
pic_height_in_ctbs_y++;
uint32_t slice_segment_address_bits =
H265::Log2Ceiling(pic_height_in_ctbs_y * pic_width_in_ctbs_y);
TRUE_OR_RETURN(slice_segment_address_bits !=
std::numeric_limits<uint32_t>::max());
slice_reader.ConsumeBits(slice_segment_address_bits);
}
if (dependent_slice_segment_flag == 0) {
for (uint32_t i = 0; i < pps->num_extra_slice_header_bits; i++) {
// slice_reserved_flag: u(1)
slice_reader.ConsumeBits(1);
}
// slice_type: ue(v)
uint32_t slice_type = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(slice_type, 0, 2);
if (pps->output_flag_present_flag) {
// pic_output_flag: u(1)
slice_reader.ConsumeBits(1);
}
if (sps->separate_colour_plane_flag) {
// colour_plane_id: u(2)
slice_reader.ConsumeBits(2);
}
uint32_t num_long_term_sps = 0;
uint32_t num_long_term_pics = 0;
std::vector<bool> used_by_curr_pic_lt_flag;
bool short_term_ref_pic_set_sps_flag = false;
uint32_t short_term_ref_pic_set_idx = 0;
H265SpsParser::ShortTermRefPicSet short_term_ref_pic_set;
bool slice_temporal_mvp_enabled_flag = 0;
if (nalu_type != H265::NaluType::kIdrWRadl &&
nalu_type != H265::NaluType::kIdrNLp) {
// slice_pic_order_cnt_lsb: u(v)
uint32_t slice_pic_order_cnt_lsb_bits =
sps->log2_max_pic_order_cnt_lsb_minus4 + 4;
slice_reader.ConsumeBits(slice_pic_order_cnt_lsb_bits);
// short_term_ref_pic_set_sps_flag: u(1)
short_term_ref_pic_set_sps_flag = slice_reader.Read<bool>();
if (!short_term_ref_pic_set_sps_flag) {
std::optional<H265SpsParser::ShortTermRefPicSet> ref_pic_set =
H265SpsParser::ParseShortTermRefPicSet(
sps->num_short_term_ref_pic_sets,
sps->num_short_term_ref_pic_sets, sps->short_term_ref_pic_set,
sps->sps_max_dec_pic_buffering_minus1
[sps->sps_max_sub_layers_minus1],
slice_reader);
TRUE_OR_RETURN(ref_pic_set);
short_term_ref_pic_set = *ref_pic_set;
} else if (sps->num_short_term_ref_pic_sets > 1) {
// short_term_ref_pic_set_idx: u(v)
uint32_t short_term_ref_pic_set_idx_bits =
H265::Log2Ceiling(sps->num_short_term_ref_pic_sets);
if ((1 << short_term_ref_pic_set_idx_bits) <
sps->num_short_term_ref_pic_sets) {
short_term_ref_pic_set_idx_bits++;
}
if (short_term_ref_pic_set_idx_bits > 0) {
short_term_ref_pic_set_idx =
slice_reader.ReadBits(short_term_ref_pic_set_idx_bits);
IN_RANGE_OR_RETURN(short_term_ref_pic_set_idx, 0,
sps->num_short_term_ref_pic_sets - 1);
}
}
if (sps->long_term_ref_pics_present_flag) {
if (sps->num_long_term_ref_pics_sps > 0) {
// num_long_term_sps: ue(v)
num_long_term_sps = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(num_long_term_sps, 0,
sps->num_long_term_ref_pics_sps);
}
// num_long_term_pics: ue(v)
num_long_term_pics = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(num_long_term_pics, 0,
kMaxLongTermRefPicSets - num_long_term_sps);
used_by_curr_pic_lt_flag.resize(num_long_term_sps + num_long_term_pics,
0);
for (uint32_t i = 0; i < num_long_term_sps + num_long_term_pics; i++) {
if (i < num_long_term_sps) {
uint32_t lt_idx_sps = 0;
if (sps->num_long_term_ref_pics_sps > 1) {
// lt_idx_sps: u(v)
uint32_t lt_idx_sps_bits =
H265::Log2Ceiling(sps->num_long_term_ref_pics_sps);
lt_idx_sps = slice_reader.ReadBits(lt_idx_sps_bits);
IN_RANGE_OR_RETURN(lt_idx_sps, 0,
sps->num_long_term_ref_pics_sps - 1);
}
used_by_curr_pic_lt_flag[i] =
sps->used_by_curr_pic_lt_sps_flag[lt_idx_sps];
} else {
// poc_lsb_lt: u(v)
uint32_t poc_lsb_lt_bits =
sps->log2_max_pic_order_cnt_lsb_minus4 + 4;
slice_reader.ConsumeBits(poc_lsb_lt_bits);
// used_by_curr_pic_lt_flag: u(1)
used_by_curr_pic_lt_flag[i] = slice_reader.Read<bool>();
}
// delta_poc_msb_present_flag: u(1)
bool delta_poc_msb_present_flag = slice_reader.Read<bool>();
if (delta_poc_msb_present_flag) {
// delta_poc_msb_cycle_lt: ue(v)
int delta_poc_msb_cycle_lt = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(
delta_poc_msb_cycle_lt, 0,
std::pow(2, 32 - sps->log2_max_pic_order_cnt_lsb_minus4 - 4));
}
}
}
if (sps->sps_temporal_mvp_enabled_flag) {
// slice_temporal_mvp_enabled_flag: u(1)
slice_temporal_mvp_enabled_flag = slice_reader.Read<bool>();
}
}
if (sps->sample_adaptive_offset_enabled_flag) {
// slice_sao_luma_flag: u(1)
slice_reader.ConsumeBits(1);
uint32_t chroma_array_type =
sps->separate_colour_plane_flag == 0 ? sps->chroma_format_idc : 0;
if (chroma_array_type != 0) {
// slice_sao_chroma_flag: u(1)
slice_reader.ConsumeBits(1);
}
}
if (slice_type == H265::SliceType::kP ||
slice_type == H265::SliceType::kB) {
// num_ref_idx_active_override_flag: u(1)
bool num_ref_idx_active_override_flag = slice_reader.Read<bool>();
uint32_t num_ref_idx_l0_active_minus1 =
pps->num_ref_idx_l0_default_active_minus1;
uint32_t num_ref_idx_l1_active_minus1 =
pps->num_ref_idx_l1_default_active_minus1;
if (num_ref_idx_active_override_flag) {
// num_ref_idx_l0_active_minus1: ue(v)
num_ref_idx_l0_active_minus1 = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(num_ref_idx_l0_active_minus1, 0,
kMaxRefIdxActive - 1);
if (slice_type == H265::SliceType::kB) {
// num_ref_idx_l1_active_minus1: ue(v)
num_ref_idx_l1_active_minus1 = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(num_ref_idx_l1_active_minus1, 0,
kMaxRefIdxActive - 1);
}
}
uint32_t num_pic_total_curr = 0;
uint32_t curr_rps_idx = 0;
if (short_term_ref_pic_set_sps_flag) {
curr_rps_idx = short_term_ref_pic_set_idx;
} else {
curr_rps_idx = sps->num_short_term_ref_pic_sets;
}
const H265SpsParser::ShortTermRefPicSet* ref_pic_set;
if (curr_rps_idx < sps->short_term_ref_pic_set.size()) {
ref_pic_set = &(sps->short_term_ref_pic_set[curr_rps_idx]);
} else {
ref_pic_set = &short_term_ref_pic_set;
}
// Equation 7-57
IN_RANGE_OR_RETURN(ref_pic_set->num_negative_pics, 0,
kMaxShortTermRefPicSets);
IN_RANGE_OR_RETURN(ref_pic_set->num_positive_pics, 0,
kMaxShortTermRefPicSets);
for (uint32_t i = 0; i < ref_pic_set->num_negative_pics; i++) {
if (ref_pic_set->used_by_curr_pic_s0[i]) {
num_pic_total_curr++;
}
}
for (uint32_t i = 0; i < ref_pic_set->num_positive_pics; i++) {
if (ref_pic_set->used_by_curr_pic_s1[i]) {
num_pic_total_curr++;
}
}
for (uint32_t i = 0; i < num_long_term_sps + num_long_term_pics; i++) {
if (used_by_curr_pic_lt_flag[i]) {
num_pic_total_curr++;
}
}
if (pps->lists_modification_present_flag && num_pic_total_curr > 1) {
// ref_pic_lists_modification()
uint32_t list_entry_bits = H265::Log2Ceiling(num_pic_total_curr);
if ((1 << list_entry_bits) < num_pic_total_curr) {
list_entry_bits++;
}
// ref_pic_list_modification_flag_l0: u(1)
bool ref_pic_list_modification_flag_l0 = slice_reader.Read<bool>();
if (ref_pic_list_modification_flag_l0) {
for (uint32_t i = 0; i < num_ref_idx_l0_active_minus1; i++) {
// list_entry_l0: u(v)
slice_reader.ConsumeBits(list_entry_bits);
}
}
if (slice_type == H265::SliceType::kB) {
// ref_pic_list_modification_flag_l1: u(1)
bool ref_pic_list_modification_flag_l1 = slice_reader.Read<bool>();
if (ref_pic_list_modification_flag_l1) {
for (uint32_t i = 0; i < num_ref_idx_l1_active_minus1; i++) {
// list_entry_l1: u(v)
slice_reader.ConsumeBits(list_entry_bits);
}
}
}
}
if (slice_type == H265::SliceType::kB) {
// mvd_l1_zero_flag: u(1)
slice_reader.ConsumeBits(1);
}
if (pps->cabac_init_present_flag) {
// cabac_init_flag: u(1)
slice_reader.ConsumeBits(1);
}
if (slice_temporal_mvp_enabled_flag) {
bool collocated_from_l0_flag = false;
if (slice_type == H265::SliceType::kB) {
// collocated_from_l0_flag: u(1)
collocated_from_l0_flag = slice_reader.Read<bool>();
}
if ((collocated_from_l0_flag && num_ref_idx_l0_active_minus1 > 0) ||
(!collocated_from_l0_flag && num_ref_idx_l1_active_minus1 > 0)) {
// collocated_ref_idx: ue(v)
uint32_t collocated_ref_idx = slice_reader.ReadExponentialGolomb();
if ((slice_type == H265::SliceType::kP ||
slice_type == H265::SliceType::kB) &&
collocated_from_l0_flag) {
IN_RANGE_OR_RETURN(collocated_ref_idx, 0,
num_ref_idx_l0_active_minus1);
}
if (slice_type == H265::SliceType::kB && !collocated_from_l0_flag) {
IN_RANGE_OR_RETURN(collocated_ref_idx, 0,
num_ref_idx_l1_active_minus1);
}
}
}
if (!slice_reader.Ok() ||
((pps->weighted_pred_flag && slice_type == H265::SliceType::kP) ||
(pps->weighted_bipred_flag && slice_type == H265::SliceType::kB))) {
// pred_weight_table()
RTC_LOG(LS_ERROR) << "Streams with pred_weight_table unsupported.";
return kUnsupportedStream;
}
// five_minus_max_num_merge_cand: ue(v)
uint32_t five_minus_max_num_merge_cand =
slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN(5 - five_minus_max_num_merge_cand, 1, 5);
}
}
// slice_qp_delta: se(v)
int32_t last_slice_qp_delta = slice_reader.ReadSignedExponentialGolomb();
if (!slice_reader.Ok() || (abs(last_slice_qp_delta) > kMaxAbsQpDeltaValue)) {
// Something has gone wrong, and the parsed value is invalid.
RTC_LOG(LS_ERROR) << "Parsed QP value out of range.";
return kInvalidStream;
}
// 7-54 in H265 spec.
IN_RANGE_OR_RETURN(26 + pps->init_qp_minus26 + last_slice_qp_delta,
-pps->qp_bd_offset_y, 51);
last_slice_qp_delta_ = last_slice_qp_delta;
last_slice_pps_id_ = pps_id;
if (!slice_reader.Ok()) {
return kInvalidStream;
}
return kOk;
}
const H265PpsParser::PpsState* H265BitstreamParser::GetPPS(uint32_t id) const {
auto it = pps_.find(id);
if (it == pps_.end()) {
RTC_LOG(LS_WARNING) << "Requested a nonexistent PPS id " << id;
return nullptr;
}
return &it->second;
}
const H265SpsParser::SpsState* H265BitstreamParser::GetSPS(uint32_t id) const {
auto it = sps_.find(id);
if (it == sps_.end()) {
RTC_LOG(LS_WARNING) << "Requested a nonexistent SPS id " << id;
return nullptr;
}
return &it->second;
}
void H265BitstreamParser::ParseSlice(rtc::ArrayView<const uint8_t> slice) {
if (slice.empty()) {
RTC_LOG(LS_WARNING) << "Empty slice in H265 bitstream.";
return;
}
H265::NaluType nalu_type = H265::ParseNaluType(slice[0]);
switch (nalu_type) {
case H265::NaluType::kVps: {
std::optional<H265VpsParser::VpsState> vps_state;
if (slice.size() >= H265::kNaluHeaderSize) {
vps_state =
H265VpsParser::ParseVps(slice.subview(H265::kNaluHeaderSize));
}
if (!vps_state) {
RTC_LOG(LS_WARNING) << "Unable to parse VPS from H265 bitstream.";
} else {
vps_[vps_state->id] = *vps_state;
}
break;
}
case H265::NaluType::kSps: {
std::optional<H265SpsParser::SpsState> sps_state;
if (slice.size() >= H265::kNaluHeaderSize) {
sps_state =
H265SpsParser::ParseSps(slice.subview(H265::kNaluHeaderSize));
}
if (!sps_state) {
RTC_LOG(LS_WARNING) << "Unable to parse SPS from H265 bitstream.";
} else {
sps_[sps_state->sps_id] = *sps_state;
}
break;
}
case H265::NaluType::kPps: {
std::optional<H265PpsParser::PpsState> pps_state;
if (slice.size() >= H265::kNaluHeaderSize) {
std::vector<uint8_t> unpacked_buffer =
H265::ParseRbsp(slice.subview(H265::kNaluHeaderSize));
BitstreamReader slice_reader(unpacked_buffer);
// pic_parameter_set_id: ue(v)
uint32_t pps_id = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN_VOID(pps_id, 0, 63);
// seq_parameter_set_id: ue(v)
uint32_t sps_id = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN_VOID(sps_id, 0, 15);
const H265SpsParser::SpsState* sps = GetSPS(sps_id);
pps_state =
H265PpsParser::ParsePps(slice.subview(H265::kNaluHeaderSize), sps);
}
if (!pps_state) {
RTC_LOG(LS_WARNING) << "Unable to parse PPS from H265 bitstream.";
} else {
pps_[pps_state->pps_id] = *pps_state;
}
break;
}
case H265::NaluType::kAud:
case H265::NaluType::kPrefixSei:
case H265::NaluType::kSuffixSei:
case H265::NaluType::kAp:
case H265::NaluType::kFu:
break;
default:
Result res = ParseNonParameterSetNalu(slice, nalu_type);
if (res != kOk) {
RTC_LOG(LS_INFO) << "Failed to parse bitstream. Error: " << res;
}
break;
}
}
std::optional<uint32_t>
H265BitstreamParser::ParsePpsIdFromSliceSegmentLayerRbsp(
rtc::ArrayView<const uint8_t> data,
uint8_t nalu_type) {
std::vector<uint8_t> unpacked_buffer = H265::ParseRbsp(data);
BitstreamReader slice_reader(unpacked_buffer);
// first_slice_segment_in_pic_flag: u(1)
slice_reader.ConsumeBits(1);
if (!slice_reader.Ok()) {
return std::nullopt;
}
if (nalu_type >= H265::NaluType::kBlaWLp &&
nalu_type <= H265::NaluType::kRsvIrapVcl23) {
// no_output_of_prior_pics_flag: u(1)
slice_reader.ConsumeBits(1);
}
// slice_pic_parameter_set_id: ue(v)
uint32_t slice_pic_parameter_set_id = slice_reader.ReadExponentialGolomb();
IN_RANGE_OR_RETURN_NULL(slice_pic_parameter_set_id, 0, 63);
if (!slice_reader.Ok()) {
return std::nullopt;
}
return slice_pic_parameter_set_id;
}
void H265BitstreamParser::ParseBitstream(
rtc::ArrayView<const uint8_t> bitstream) {
std::vector<H265::NaluIndex> nalu_indices = H265::FindNaluIndices(bitstream);
for (const H265::NaluIndex& index : nalu_indices)
ParseSlice(
bitstream.subview(index.payload_start_offset, index.payload_size));
}
std::optional<int> H265BitstreamParser::GetLastSliceQp() const {
if (!last_slice_qp_delta_ || !last_slice_pps_id_) {
return std::nullopt;
}
const H265PpsParser::PpsState* pps = GetPPS(last_slice_pps_id_.value());
if (!pps)
return std::nullopt;
const int parsed_qp = 26 + pps->init_qp_minus26 + *last_slice_qp_delta_;
if (parsed_qp < kMinQpValue || parsed_qp > kMaxQpValue) {
RTC_LOG(LS_ERROR) << "Parsed invalid QP from bitstream.";
return std::nullopt;
}
return parsed_qp;
}
std::optional<uint32_t> H265BitstreamParser::GetLastSlicePpsId() const {
if (!last_slice_pps_id_) {
RTC_LOG(LS_ERROR) << "Failed to parse PPS id from bitstream.";
return std::nullopt;
}
return last_slice_pps_id_;
}
} // namespace webrtc