Propagate active decode targets bitmask into DependencyDescriptor

Bug: webrtc:10342
Change-Id: I5e8a204881b94fe5786b14e27cefce2fe056e91b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/178140
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31579}

call/rtp_payload_params.cc

@@ -245,6 +245,7 @@ RtpPayloadParams::GenericDescriptorFromFrameInfo(
   generic.spatial_index = frame_info.spatial_id;
   generic.temporal_index = frame_info.temporal_id;
   generic.decode_target_indications = frame_info.decode_target_indications;
+  generic.active_decode_targets = frame_info.active_decode_targets;
   return generic;
 }
 

modules/rtp_rtcp/source/active_decode_targets_helper.cc

@@ -93,6 +93,7 @@ void ActiveDecodeTargetsHelper::OnFrame(
   if (is_keyframe) {
     // Key frame resets the state.
     last_active_decode_targets_ = all_decode_targets;
+    last_active_chains_ = AllActive(num_chains);
     unsent_on_chain_.reset();
   } else {
     // Update state assuming previous frame was sent.
@@ -108,12 +109,12 @@ void ActiveDecodeTargetsHelper::OnFrame(
     return;
   }
   last_active_decode_targets_ = active_decode_targets;
-
+  last_active_chains_ = ActiveChains(decode_target_protected_by_chain,
+                                     num_chains, active_decode_targets);
   // Frames that are part of inactive chains might not be produced by the
   // encoder. Thus stop sending `active_decode_target` bitmask when it is sent
   // on all active chains rather than on all chains.
-  unsent_on_chain_ = ActiveChains(decode_target_protected_by_chain, num_chains,
+  unsent_on_chain_ = last_active_chains_;
-                                  active_decode_targets);
   if (unsent_on_chain_.none()) {
     // Active decode targets are not protected by any chains. To be on the
     // safe side always send the active_decode_targets_bitmask from now on.

modules/rtp_rtcp/source/active_decode_targets_helper.h

@@ -47,11 +47,14 @@ class ActiveDecodeTargetsHelper {
     return last_active_decode_targets_.to_ulong();
   }
 
+  std::bitset<32> ActiveChainsBitmask() const { return last_active_chains_; }
+
  private:
   // `unsent_on_chain_[i]` indicates last active decode
   // target bitmask wasn't attached to a packet on the chain with id `i`.
   std::bitset<32> unsent_on_chain_ = 0;
   std::bitset<32> last_active_decode_targets_ = 0;
+  std::bitset<32> last_active_chains_ = 0;
   int64_t last_frame_id_ = 0;
 };
 

modules/rtp_rtcp/source/rtp_sender_video.cc

@@ -335,6 +335,10 @@ void RTPSenderVideo::AddRtpHeaderExtensions(
           descriptor.frame_dependencies.decode_target_indications.size(),
           video_structure_->num_decode_targets);
 
+      if (first_packet) {
+        descriptor.active_decode_targets_bitmask =
+            active_decode_targets_tracker_.ActiveDecodeTargetsBitmask();
+      }
       // To avoid extra structure copy, temporary share ownership of the
       // video_structure with the dependency descriptor.
       if (video_header.frame_type == VideoFrameType::kVideoFrameKey &&
@@ -343,7 +347,8 @@ void RTPSenderVideo::AddRtpHeaderExtensions(
             absl::WrapUnique(video_structure_.get());
       }
       extension_is_set = packet->SetExtension<RtpDependencyDescriptorExtension>(
-          *video_structure_, descriptor);
+          *video_structure_,
+          active_decode_targets_tracker_.ActiveChainsBitmask(), descriptor);
 
       // Remove the temporary shared ownership.
       descriptor.attached_structure.release();
@@ -415,6 +420,14 @@ bool RTPSenderVideo::SendVideo(
     playout_delay_pending_ = true;
   }
 
+  if (video_structure_ != nullptr && video_header.generic) {
+    active_decode_targets_tracker_.OnFrame(
+        video_structure_->decode_target_protected_by_chain,
+        video_header.generic->active_decode_targets,
+        video_header.frame_type == VideoFrameType::kVideoFrameKey,
+        video_header.generic->frame_id, video_header.generic->chain_diffs);
+  }
+
   // Maximum size of packet including rtp headers.
   // Extra space left in case packet will be resent using fec or rtx.
   int packet_capacity = rtp_sender_->MaxRtpPacketSize() - FecPacketOverhead() -

modules/rtp_rtcp/source/rtp_sender_video.h

@@ -27,6 +27,7 @@
 #include "modules/include/module_common_types.h"
 #include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "modules/rtp_rtcp/source/absolute_capture_time_sender.h"
+#include "modules/rtp_rtcp/source/active_decode_targets_helper.h"
 #include "modules/rtp_rtcp/source/rtp_rtcp_config.h"
 #include "modules/rtp_rtcp/source/rtp_sender.h"
 #include "modules/rtp_rtcp/source/rtp_sender_video_frame_transformer_delegate.h"
@@ -214,6 +215,9 @@ class RTPSenderVideo {
   const bool generic_descriptor_auth_experiment_;
 
   AbsoluteCaptureTimeSender absolute_capture_time_sender_;
+  // Tracks updates to the active decode targets and decides when active decode
+  // targets bitmask should be attached to the dependency descriptor.
+  ActiveDecodeTargetsHelper active_decode_targets_tracker_;
 
   const rtc::scoped_refptr<RTPSenderVideoFrameTransformerDelegate>
       frame_transformer_delegate_;

modules/rtp_rtcp/source/rtp_sender_video_unittest.cc

@@ -593,6 +593,40 @@ TEST_P(RtpSenderVideoTest, PropagatesChainDiffsIntoDependencyDescriptor) {
               ContainerEq(generic.chain_diffs));
 }
 
+TEST_P(RtpSenderVideoTest,
+       PropagatesActiveDecodeTargetsIntoDependencyDescriptor) {
+  const int64_t kFrameId = 100000;
+  uint8_t kFrame[100];
+  rtp_module_->RegisterRtpHeaderExtension(
+      RtpDependencyDescriptorExtension::kUri, kDependencyDescriptorId);
+  FrameDependencyStructure video_structure;
+  video_structure.num_decode_targets = 2;
+  video_structure.num_chains = 1;
+  video_structure.decode_target_protected_by_chain = {0, 0};
+  video_structure.templates = {
+      FrameDependencyTemplate().S(0).T(0).Dtis("SS").ChainDiffs({1}),
+  };
+  rtp_sender_video_.SetVideoStructure(&video_structure);
+
+  RTPVideoHeader hdr;
+  RTPVideoHeader::GenericDescriptorInfo& generic = hdr.generic.emplace();
+  generic.frame_id = kFrameId;
+  generic.decode_target_indications = {DecodeTargetIndication::kSwitch,
+                                       DecodeTargetIndication::kSwitch};
+  generic.active_decode_targets = 0b01;
+  generic.chain_diffs = {1};
+  hdr.frame_type = VideoFrameType::kVideoFrameKey;
+  rtp_sender_video_.SendVideo(kPayload, kType, kTimestamp, 0, kFrame, nullptr,
+                              hdr, kDefaultExpectedRetransmissionTimeMs);
+
+  ASSERT_EQ(transport_.packets_sent(), 1);
+  DependencyDescriptor descriptor_key;
+  ASSERT_TRUE(transport_.last_sent_packet()
+                  .GetExtension<RtpDependencyDescriptorExtension>(
+                      nullptr, &descriptor_key));
+  EXPECT_EQ(descriptor_key.active_decode_targets_bitmask, 0b01u);
+}
+
 TEST_P(RtpSenderVideoTest,
        SetDiffentVideoStructureAvoidsCollisionWithThePreviousStructure) {
   const int64_t kFrameId = 100000;

modules/rtp_rtcp/source/rtp_video_header.h

@@ -10,6 +10,7 @@
 #ifndef MODULES_RTP_RTCP_SOURCE_RTP_VIDEO_HEADER_H_
 #define MODULES_RTP_RTCP_SOURCE_RTP_VIDEO_HEADER_H_
 
+#include <bitset>
 #include <cstdint>
 
 #include "absl/container/inlined_vector.h"
@@ -53,6 +54,7 @@ struct RTPVideoHeader {
     absl::InlinedVector<DecodeTargetIndication, 10> decode_target_indications;
     absl::InlinedVector<int64_t, 5> dependencies;
     absl::InlinedVector<int, 4> chain_diffs;
+    std::bitset<32> active_decode_targets = ~uint32_t{0};
   };
 
   RTPVideoHeader();