Share constants for dependency descriptor rtp header extension

Bug: webrtc:10342
Change-Id: I9c81215569bd1bd96b953faa359f5a3d32c7d0c4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/177521
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31549}

api/transport/rtp/dependency_descriptor.cc

@@ -15,6 +15,12 @@
 #include "rtc_base/checks.h"
 
 namespace webrtc {
+
+constexpr int DependencyDescriptor::kMaxSpatialIds;
+constexpr int DependencyDescriptor::kMaxTemporalIds;
+constexpr int DependencyDescriptor::kMaxTemplates;
+constexpr int DependencyDescriptor::kMaxDecodeTargets;
+
 namespace webrtc_impl {
 
 absl::InlinedVector<DecodeTargetIndication, 10> StringToDecodeTargetIndications(

api/transport/rtp/dependency_descriptor.h

@@ -99,6 +99,11 @@ struct FrameDependencyStructure {
 };
 
 struct DependencyDescriptor {
+  static constexpr int kMaxSpatialIds = 4;
+  static constexpr int kMaxTemporalIds = 8;
+  static constexpr int kMaxDecodeTargets = 32;
+  static constexpr int kMaxTemplates = 64;
+
   bool first_packet_in_frame = true;
   bool last_packet_in_frame = true;
   int frame_number = 0;

modules/rtp_rtcp/source/rtp_dependency_descriptor_reader.cc

@@ -18,13 +18,6 @@
 #include "rtc_base/checks.h"
 
 namespace webrtc {
-namespace {
-
-constexpr int kMaxTemporalId = 7;
-constexpr int kMaxSpatialId = 3;
-constexpr int kMaxTemplates = 64;
-
-}  // namespace
 
 RtpDependencyDescriptorReader::RtpDependencyDescriptorReader(
     rtc::ArrayView<const uint8_t> raw_data,
@@ -95,7 +88,7 @@ void RtpDependencyDescriptorReader::ReadTemplateLayers() {
   int spatial_id = 0;
   NextLayerIdc next_layer_idc;
   do {
-    if (templates.size() == kMaxTemplates) {
+    if (templates.size() == DependencyDescriptor::kMaxTemplates) {
       parsing_failed_ = true;
       break;
     }
@@ -107,14 +100,14 @@ void RtpDependencyDescriptorReader::ReadTemplateLayers() {
     next_layer_idc = static_cast<NextLayerIdc>(ReadBits(2));
     if (next_layer_idc == kNextTemporalLayer) {
       temporal_id++;
-      if (temporal_id > kMaxTemporalId) {
+      if (temporal_id >= DependencyDescriptor::kMaxTemporalIds) {
         parsing_failed_ = true;
         break;
       }
     } else if (next_layer_idc == kNextSpatialLayer) {
       temporal_id = 0;
       spatial_id++;
-      if (spatial_id > kMaxSpatialId) {
+      if (spatial_id >= DependencyDescriptor::kMaxSpatialIds) {
         parsing_failed_ = true;
         break;
       }
@@ -198,9 +191,10 @@ void RtpDependencyDescriptorReader::ReadExtendedFields() {
 }
 
 void RtpDependencyDescriptorReader::ReadFrameDependencyDefinition() {
-  size_t template_index = (frame_dependency_template_id_ + kMaxTemplates -
-                           structure_->structure_id) %
-                          kMaxTemplates;
+  size_t template_index =
+      (frame_dependency_template_id_ + DependencyDescriptor::kMaxTemplates -
+       structure_->structure_id) %
+      DependencyDescriptor::kMaxTemplates;
 
   if (template_index >= structure_->templates.size()) {
     parsing_failed_ = true;

modules/rtp_rtcp/source/rtp_dependency_descriptor_writer.cc

@@ -23,8 +23,6 @@
 namespace webrtc {
 namespace {
 
-constexpr int kMaxTemplates = 64;
-
 enum class NextLayerIdc : uint64_t {
   kSameLayer = 0,
   kNextTemporal = 1,
@@ -35,12 +33,8 @@ enum class NextLayerIdc : uint64_t {
 
 NextLayerIdc GetNextLayerIdc(const FrameDependencyTemplate& previous,
                              const FrameDependencyTemplate& next) {
-  // TODO(danilchap): Move these constants to header shared between reader and
-  // writer.
-  static constexpr int kMaxSpatialId = 3;
-  static constexpr int kMaxTemporalId = 7;
-  RTC_DCHECK_LE(next.spatial_id, kMaxSpatialId);
-  RTC_DCHECK_LE(next.temporal_id, kMaxTemporalId);
+  RTC_DCHECK_LT(next.spatial_id, DependencyDescriptor::kMaxSpatialIds);
+  RTC_DCHECK_LT(next.temporal_id, DependencyDescriptor::kMaxTemporalIds);
 
   if (next.spatial_id == previous.spatial_id &&
       next.temporal_id == previous.temporal_id) {
@@ -201,7 +195,7 @@ bool RtpDependencyDescriptorWriter::HasExtendedFields() const {
 uint64_t RtpDependencyDescriptorWriter::TemplateId() const {
   return (best_template_.template_position - structure_.templates.begin() +
           structure_.structure_id) %
-         kMaxTemplates;
+         DependencyDescriptor::kMaxTemplates;
 }
 
 void RtpDependencyDescriptorWriter::WriteBits(uint64_t val, size_t bit_count) {
@@ -217,9 +211,10 @@ void RtpDependencyDescriptorWriter::WriteNonSymmetric(uint32_t value,
 
 void RtpDependencyDescriptorWriter::WriteTemplateDependencyStructure() {
   RTC_DCHECK_GE(structure_.structure_id, 0);
-  RTC_DCHECK_LT(structure_.structure_id, kMaxTemplates);
+  RTC_DCHECK_LT(structure_.structure_id, DependencyDescriptor::kMaxTemplates);
   RTC_DCHECK_GT(structure_.num_decode_targets, 0);
-  RTC_DCHECK_LE(structure_.num_decode_targets, 1 << 5);
+  RTC_DCHECK_LE(structure_.num_decode_targets,
+                DependencyDescriptor::kMaxDecodeTargets);
 
   WriteBits(structure_.structure_id, 6);
   WriteBits(structure_.num_decode_targets - 1, 5);
@@ -236,7 +231,7 @@ void RtpDependencyDescriptorWriter::WriteTemplateDependencyStructure() {
 void RtpDependencyDescriptorWriter::WriteTemplateLayers() {
   const auto& templates = structure_.templates;
   RTC_DCHECK(!templates.empty());
-  RTC_DCHECK_LE(templates.size(), kMaxTemplates);
+  RTC_DCHECK_LE(templates.size(), DependencyDescriptor::kMaxTemplates);
   RTC_DCHECK_EQ(templates[0].spatial_id, 0);
   RTC_DCHECK_EQ(templates[0].temporal_id, 0);
 

modules/video_coding/codecs/av1/BUILD.gn

@@ -127,6 +127,7 @@ if (rtc_include_tests) {
       ":scalable_video_controller",
       "../..:chain_diff_calculator",
       "../..:frame_dependencies_calculator",
+      "../../../../api/transport/rtp:dependency_descriptor",
       "../../../../api/video:video_frame_type",
       "../../../../test:test_support",
     ]

modules/video_coding/codecs/av1/scalability_structure_unittest.cc

@@ -17,6 +17,7 @@
 #include <string>
 
 #include "absl/types/optional.h"
+#include "api/transport/rtp/dependency_descriptor.h"
 #include "api/video/video_frame_type.h"
 #include "modules/video_coding/chain_diff_calculator.h"
 #include "modules/video_coding/codecs/av1/scalability_structure_l1t2.h"
@@ -105,7 +106,8 @@ TEST_P(ScalabilityStructureTest,
   FrameDependencyStructure structure =
       GetParam().svc_factory()->DependencyStructure();
   EXPECT_GT(structure.num_decode_targets, 0);
-  EXPECT_LE(structure.num_decode_targets, 32);
+  EXPECT_LE(structure.num_decode_targets,
+            DependencyDescriptor::kMaxDecodeTargets);
   EXPECT_GE(structure.num_chains, 0);
   EXPECT_LE(structure.num_chains, structure.num_decode_targets);
   if (structure.num_chains == 0) {
@@ -115,7 +117,8 @@ TEST_P(ScalabilityStructureTest,
                 AllOf(SizeIs(structure.num_decode_targets), Each(Ge(0)),
                       Each(Le(structure.num_chains))));
   }
-  EXPECT_THAT(structure.templates, SizeIs(Lt(size_t{64})));
+  EXPECT_THAT(structure.templates,
+              SizeIs(Lt(size_t{DependencyDescriptor::kMaxTemplates})));
 }
 
 TEST_P(ScalabilityStructureTest, TemplatesAreSortedByLayerId) {