Migrate Dependency Descriptor parser from BitBuffer to BitstreamReader
BitstreamReader itself uses idea of Read function that always succeed,
and a separate function to check for errors.
Thus extra layer in the DependencyDescriptorReader is not needed.
Bug: None
Change-Id: Ie58861f2cbecc02a5a1a9538232494b4442c9afd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231226
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#34940}
diff --git a/modules/rtp_rtcp/BUILD.gn b/modules/rtp_rtcp/BUILD.gn
index d3f2fe0..950e832 100644
--- a/modules/rtp_rtcp/BUILD.gn
+++ b/modules/rtp_rtcp/BUILD.gn
@@ -118,6 +118,7 @@
"../../api/video:video_layers_allocation",
"../../api/video:video_rtp_headers",
"../../common_video",
+ "../../rtc_base:bitstream_reader",
"../../rtc_base:checks",
"../../rtc_base:divide_round",
"../../rtc_base:rtc_base_approved",
diff --git a/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.cc b/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.cc
index 8f0cb34..1a56efd 100644
--- a/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.cc
+++ b/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.cc
@@ -14,7 +14,7 @@
#include <vector>
#include "api/transport/rtp/dependency_descriptor.h"
-#include "rtc_base/bit_buffer.h"
+#include "rtc_base/bitstream_reader.h"
#include "rtc_base/checks.h"
namespace webrtc {
@@ -23,7 +23,7 @@
rtc::ArrayView<const uint8_t> raw_data,
const FrameDependencyStructure* structure,
DependencyDescriptor* descriptor)
- : descriptor_(descriptor), buffer_(raw_data.data(), raw_data.size()) {
+ : descriptor_(descriptor), buffer_(raw_data) {
RTC_DCHECK(descriptor);
ReadMandatoryFields();
@@ -33,50 +33,35 @@
structure_ = descriptor->attached_structure
? descriptor->attached_structure.get()
: structure;
- if (structure_ == nullptr || parsing_failed_) {
- parsing_failed_ = true;
+ if (structure_ == nullptr) {
+ buffer_.Invalidate();
return;
}
if (active_decode_targets_present_flag_) {
descriptor->active_decode_targets_bitmask =
- ReadBits(structure_->num_decode_targets);
+ buffer_.ReadBits(structure_->num_decode_targets);
}
ReadFrameDependencyDefinition();
}
-uint32_t RtpDependencyDescriptorReader::ReadBits(size_t bit_count) {
- uint32_t value = 0;
- if (!buffer_.ReadBits(bit_count, value))
- parsing_failed_ = true;
- return value;
-}
-
-uint32_t RtpDependencyDescriptorReader::ReadNonSymmetric(size_t num_values) {
- uint32_t value = 0;
- if (!buffer_.ReadNonSymmetric(num_values, value))
- parsing_failed_ = true;
- return value;
-}
-
void RtpDependencyDescriptorReader::ReadTemplateDependencyStructure() {
descriptor_->attached_structure =
std::make_unique<FrameDependencyStructure>();
- descriptor_->attached_structure->structure_id = ReadBits(6);
- descriptor_->attached_structure->num_decode_targets = ReadBits(5) + 1;
+ descriptor_->attached_structure->structure_id = buffer_.ReadBits(6);
+ descriptor_->attached_structure->num_decode_targets = buffer_.ReadBits(5) + 1;
ReadTemplateLayers();
ReadTemplateDtis();
ReadTemplateFdiffs();
ReadTemplateChains();
- uint32_t has_resolutions = ReadBits(1);
- if (has_resolutions)
+ if (buffer_.Read<bool>())
ReadResolutions();
}
void RtpDependencyDescriptorReader::ReadTemplateLayers() {
- enum NextLayerIdc : uint32_t {
+ enum NextLayerIdc {
kSameLayer = 0,
kNextTemporalLayer = 1,
kNextSpatialLayer = 2,
@@ -89,7 +74,7 @@
NextLayerIdc next_layer_idc;
do {
if (templates.size() == DependencyDescriptor::kMaxTemplates) {
- parsing_failed_ = true;
+ buffer_.Invalidate();
break;
}
templates.emplace_back();
@@ -97,22 +82,22 @@
last_template.temporal_id = temporal_id;
last_template.spatial_id = spatial_id;
- next_layer_idc = static_cast<NextLayerIdc>(ReadBits(2));
+ next_layer_idc = static_cast<NextLayerIdc>(buffer_.ReadBits(2));
if (next_layer_idc == kNextTemporalLayer) {
temporal_id++;
if (temporal_id >= DependencyDescriptor::kMaxTemporalIds) {
- parsing_failed_ = true;
+ buffer_.Invalidate();
break;
}
} else if (next_layer_idc == kNextSpatialLayer) {
temporal_id = 0;
spatial_id++;
if (spatial_id >= DependencyDescriptor::kMaxSpatialIds) {
- parsing_failed_ = true;
+ buffer_.Invalidate();
break;
}
}
- } while (next_layer_idc != kNoMoreTemplates && !parsing_failed_);
+ } while (next_layer_idc != kNoMoreTemplates && buffer_.Ok());
descriptor_->attached_structure->templates = std::move(templates);
}
@@ -124,7 +109,7 @@
structure->num_decode_targets);
for (int i = 0; i < structure->num_decode_targets; ++i) {
current_template.decode_target_indications[i] =
- static_cast<DecodeTargetIndication>(ReadBits(2));
+ static_cast<DecodeTargetIndication>(buffer_.ReadBits(2));
}
}
}
@@ -132,9 +117,9 @@
void RtpDependencyDescriptorReader::ReadTemplateFdiffs() {
for (FrameDependencyTemplate& current_template :
descriptor_->attached_structure->templates) {
- for (uint32_t fdiff_follows = ReadBits(1); fdiff_follows;
- fdiff_follows = ReadBits(1)) {
- uint32_t fdiff_minus_one = ReadBits(4);
+ for (bool fdiff_follows = buffer_.Read<bool>(); fdiff_follows;
+ fdiff_follows = buffer_.Read<bool>()) {
+ uint64_t fdiff_minus_one = buffer_.ReadBits(4);
current_template.frame_diffs.push_back(fdiff_minus_one + 1);
}
}
@@ -142,16 +127,18 @@
void RtpDependencyDescriptorReader::ReadTemplateChains() {
FrameDependencyStructure* structure = descriptor_->attached_structure.get();
- structure->num_chains = ReadNonSymmetric(structure->num_decode_targets + 1);
+ structure->num_chains =
+ buffer_.ReadNonSymmetric(structure->num_decode_targets + 1);
if (structure->num_chains == 0)
return;
for (int i = 0; i < structure->num_decode_targets; ++i) {
- uint32_t protected_by_chain = ReadNonSymmetric(structure->num_chains);
+ uint32_t protected_by_chain =
+ buffer_.ReadNonSymmetric(structure->num_chains);
structure->decode_target_protected_by_chain.push_back(protected_by_chain);
}
for (FrameDependencyTemplate& frame_template : structure->templates) {
for (int chain_id = 0; chain_id < structure->num_chains; ++chain_id) {
- frame_template.chain_diffs.push_back(ReadBits(4));
+ frame_template.chain_diffs.push_back(buffer_.ReadBits(4));
}
}
}
@@ -162,25 +149,25 @@
int spatial_layers = structure->templates.back().spatial_id + 1;
structure->resolutions.reserve(spatial_layers);
for (int sid = 0; sid < spatial_layers; ++sid) {
- uint16_t width_minus_1 = ReadBits(16);
- uint16_t height_minus_1 = ReadBits(16);
+ uint16_t width_minus_1 = buffer_.Read<uint16_t>();
+ uint16_t height_minus_1 = buffer_.Read<uint16_t>();
structure->resolutions.emplace_back(width_minus_1 + 1, height_minus_1 + 1);
}
}
void RtpDependencyDescriptorReader::ReadMandatoryFields() {
- descriptor_->first_packet_in_frame = ReadBits(1);
- descriptor_->last_packet_in_frame = ReadBits(1);
- frame_dependency_template_id_ = ReadBits(6);
- descriptor_->frame_number = ReadBits(16);
+ descriptor_->first_packet_in_frame = buffer_.Read<bool>();
+ descriptor_->last_packet_in_frame = buffer_.Read<bool>();
+ frame_dependency_template_id_ = buffer_.ReadBits(6);
+ descriptor_->frame_number = buffer_.Read<uint16_t>();
}
void RtpDependencyDescriptorReader::ReadExtendedFields() {
- bool template_dependency_structure_present_flag = ReadBits(1);
- active_decode_targets_present_flag_ = ReadBits(1);
- custom_dtis_flag_ = ReadBits(1);
- custom_fdiffs_flag_ = ReadBits(1);
- custom_chains_flag_ = ReadBits(1);
+ bool template_dependency_structure_present_flag = buffer_.Read<bool>();
+ active_decode_targets_present_flag_ = buffer_.Read<bool>();
+ custom_dtis_flag_ = buffer_.Read<bool>();
+ custom_fdiffs_flag_ = buffer_.Read<bool>();
+ custom_chains_flag_ = buffer_.Read<bool>();
if (template_dependency_structure_present_flag) {
ReadTemplateDependencyStructure();
RTC_DCHECK(descriptor_->attached_structure);
@@ -197,7 +184,7 @@
DependencyDescriptor::kMaxTemplates;
if (template_index >= structure_->templates.size()) {
- parsing_failed_ = true;
+ buffer_.Invalidate();
return;
}
@@ -228,15 +215,15 @@
descriptor_->frame_dependencies.decode_target_indications.size(),
structure_->num_decode_targets);
for (auto& dti : descriptor_->frame_dependencies.decode_target_indications) {
- dti = static_cast<DecodeTargetIndication>(ReadBits(2));
+ dti = static_cast<DecodeTargetIndication>(buffer_.ReadBits(2));
}
}
void RtpDependencyDescriptorReader::ReadFrameFdiffs() {
descriptor_->frame_dependencies.frame_diffs.clear();
- for (uint32_t next_fdiff_size = ReadBits(2); next_fdiff_size > 0;
- next_fdiff_size = ReadBits(2)) {
- uint32_t fdiff_minus_one = ReadBits(4 * next_fdiff_size);
+ for (uint64_t next_fdiff_size = buffer_.ReadBits(2); next_fdiff_size > 0;
+ next_fdiff_size = buffer_.ReadBits(2)) {
+ uint64_t fdiff_minus_one = buffer_.ReadBits(4 * next_fdiff_size);
descriptor_->frame_dependencies.frame_diffs.push_back(fdiff_minus_one + 1);
}
}
@@ -245,7 +232,7 @@
RTC_DCHECK_EQ(descriptor_->frame_dependencies.chain_diffs.size(),
structure_->num_chains);
for (auto& chain_diff : descriptor_->frame_dependencies.chain_diffs) {
- chain_diff = ReadBits(8);
+ chain_diff = buffer_.Read<uint8_t>();
}
}
diff --git a/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.h b/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.h
index 6472216..f79d3d1 100644
--- a/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.h
+++ b/modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.h
@@ -16,7 +16,7 @@
#include "api/array_view.h"
#include "api/transport/rtp/dependency_descriptor.h"
-#include "rtc_base/bit_buffer.h"
+#include "rtc_base/bitstream_reader.h"
namespace webrtc {
// Deserializes DependencyDescriptor rtp header extension.
@@ -31,14 +31,9 @@
const RtpDependencyDescriptorReader&) = delete;
// Returns true if parse was successful.
- bool ParseSuccessful() { return !parsing_failed_; }
+ bool ParseSuccessful() { return buffer_.Ok(); }
private:
- // Reads bits from `buffer_`. If it fails, returns 0 and marks parsing as
- // failed, but doesn't stop the parsing.
- uint32_t ReadBits(size_t bit_count);
- uint32_t ReadNonSymmetric(size_t num_values);
-
// Functions to read template dependency structure.
void ReadTemplateDependencyStructure();
void ReadTemplateLayers();
@@ -57,11 +52,10 @@
void ReadFrameChains();
// Output.
- bool parsing_failed_ = false;
DependencyDescriptor* const descriptor_;
// Values that are needed while reading the descriptor, but can be discarded
// when reading is complete.
- rtc::BitBuffer buffer_;
+ BitstreamReader buffer_;
int frame_dependency_template_id_ = 0;
bool active_decode_targets_present_flag_ = false;
bool custom_dtis_flag_ = false;
