Adding OnReceivedOverhead to AudioEncoder.

BUG=webrtc:6762

Review-Url: https://codereview.webrtc.org/2528933002
Cr-Commit-Position: refs/heads/master@{#15457}

webrtc/modules/audio_coding/codecs/audio_encoder.cc

@@ -81,6 +81,8 @@ void AudioEncoder::OnReceivedTargetAudioBitrate(int target_audio_bitrate_bps) {}
 
 void AudioEncoder::OnReceivedRtt(int rtt_ms) {}
 
+void AudioEncoder::OnReceivedOverhead(size_t overhead_bytes_per_packet) {}
+
 void AudioEncoder::SetReceiverFrameLengthRange(int min_frame_length_ms,
                                                int max_frame_length_ms) {}
 

webrtc/modules/audio_coding/codecs/audio_encoder.h

@@ -181,6 +181,10 @@ class AudioEncoder {
   // Provides RTT to this encoder to allow it to adapt.
   virtual void OnReceivedRtt(int rtt_ms);
 
+  // Provides overhead to this encoder to adapt. The overhead is the number of
+  // bytes that will be added to each packet the encoder generates.
+  virtual void OnReceivedOverhead(size_t overhead_bytes_per_packet);
+
   // To allow encoder to adapt its frame length, it must be provided the frame
   // length range that receivers can accept.
   virtual void SetReceiverFrameLengthRange(int min_frame_length_ms,

webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.cc

@@ -15,12 +15,14 @@
 
 #include "webrtc/base/analytics/exp_filter.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
 #include "webrtc/base/safe_conversions.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/audio_network_adaptor/audio_network_adaptor_impl.h"
 #include "webrtc/modules/audio_coding/audio_network_adaptor/controller_manager.h"
 #include "webrtc/modules/audio_coding/codecs/opus/opus_interface.h"
 #include "webrtc/system_wrappers/include/clock.h"
+#include "webrtc/system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 
@@ -291,10 +293,25 @@ void AudioEncoderOpus::OnReceivedUplinkPacketLossFraction(
 
 void AudioEncoderOpus::OnReceivedTargetAudioBitrate(
     int target_audio_bitrate_bps) {
-  if (!audio_network_adaptor_)
-    return SetTargetBitrate(target_audio_bitrate_bps);
-  audio_network_adaptor_->SetTargetAudioBitrate(target_audio_bitrate_bps);
-  ApplyAudioNetworkAdaptor();
+  if (audio_network_adaptor_) {
+    audio_network_adaptor_->SetTargetAudioBitrate(target_audio_bitrate_bps);
+    ApplyAudioNetworkAdaptor();
+  } else if (webrtc::field_trial::FindFullName(
+                 "WebRTC-SendSideBwe-WithOverhead") == "Enabled") {
+    if (!overhead_bytes_per_packet_) {
+      LOG(LS_INFO)
+          << "AudioEncoderOpus: Overhead unknown, target audio bitrate "
+          << target_audio_bitrate_bps << " bps is ignored.";
+      return;
+    }
+    const int overhead_bps = static_cast<int>(
+        *overhead_bytes_per_packet_ * 8 * 100 / Num10MsFramesInNextPacket());
+    SetTargetBitrate(std::min(
+        kMaxBitrateBps,
+        std::max(kMinBitrateBps, target_audio_bitrate_bps - overhead_bps)));
+  } else {
+    SetTargetBitrate(target_audio_bitrate_bps);
+  }
 }
 
 void AudioEncoderOpus::OnReceivedRtt(int rtt_ms) {
@@ -304,6 +321,16 @@ void AudioEncoderOpus::OnReceivedRtt(int rtt_ms) {
   ApplyAudioNetworkAdaptor();
 }
 
+void AudioEncoderOpus::OnReceivedOverhead(size_t overhead_bytes_per_packet) {
+  if (audio_network_adaptor_) {
+    audio_network_adaptor_->SetOverhead(overhead_bytes_per_packet);
+    ApplyAudioNetworkAdaptor();
+  } else {
+    overhead_bytes_per_packet_ =
+        rtc::Optional<size_t>(overhead_bytes_per_packet);
+  }
+}
+
 void AudioEncoderOpus::SetReceiverFrameLengthRange(int min_frame_length_ms,
                                                    int max_frame_length_ms) {
   // Ensure that |SetReceiverFrameLengthRange| is called before

webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.h

@@ -110,6 +110,7 @@ class AudioEncoderOpus final : public AudioEncoder {
       float uplink_packet_loss_fraction) override;
   void OnReceivedTargetAudioBitrate(int target_audio_bitrate_bps) override;
   void OnReceivedRtt(int rtt_ms) override;
+  void OnReceivedOverhead(size_t overhead_bytes_per_packet) override;
   void SetReceiverFrameLengthRange(int min_frame_length_ms,
                                    int max_frame_length_ms) override;
   rtc::ArrayView<const int> supported_frame_lengths_ms() const {
@@ -159,6 +160,7 @@ class AudioEncoderOpus final : public AudioEncoder {
   std::unique_ptr<PacketLossFractionSmoother> packet_loss_fraction_smoother_;
   AudioNetworkAdaptorCreator audio_network_adaptor_creator_;
   std::unique_ptr<AudioNetworkAdaptor> audio_network_adaptor_;
+  rtc::Optional<size_t> overhead_bytes_per_packet_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioEncoderOpus);
 };

webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus_unittest.cc

@@ -14,6 +14,7 @@
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/audio_network_adaptor/mock/mock_audio_network_adaptor.h"
 #include "webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.h"
+#include "webrtc/test/field_trial.h"
 #include "webrtc/test/gmock.h"
 #include "webrtc/test/gtest.h"
 #include "webrtc/system_wrappers/include/clock.h"
@@ -249,7 +250,7 @@ TEST(AudioEncoderOpusTest, SetReceiverFrameLengthRange) {
   EXPECT_THAT(states.encoder->supported_frame_lengths_ms(), ElementsAre(20));
 }
 
-TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetUplinkBandwidth) {
+TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnReceivedUplinkBandwidth) {
   auto states = CreateCodec(2);
   states.encoder->EnableAudioNetworkAdaptor("", nullptr);
 
@@ -267,7 +268,7 @@ TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetUplinkBandwidth) {
 }
 
 TEST(AudioEncoderOpusTest,
-     InvokeAudioNetworkAdaptorOnSetUplinkPacketLossFraction) {
+     InvokeAudioNetworkAdaptorOnReceivedUplinkPacketLossFraction) {
   auto states = CreateCodec(2);
   states.encoder->EnableAudioNetworkAdaptor("", nullptr);
 
@@ -284,7 +285,8 @@ TEST(AudioEncoderOpusTest,
   CheckEncoderRuntimeConfig(states.encoder.get(), config);
 }
 
-TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetTargetAudioBitrate) {
+TEST(AudioEncoderOpusTest,
+     InvokeAudioNetworkAdaptorOnReceivedTargetAudioBitrate) {
   auto states = CreateCodec(2);
   states.encoder->EnableAudioNetworkAdaptor("", nullptr);
 
@@ -301,7 +303,7 @@ TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetTargetAudioBitrate) {
   CheckEncoderRuntimeConfig(states.encoder.get(), config);
 }
 
-TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetRtt) {
+TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnReceivedRtt) {
   auto states = CreateCodec(2);
   states.encoder->EnableAudioNetworkAdaptor("", nullptr);
 
@@ -317,6 +319,22 @@ TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnSetRtt) {
   CheckEncoderRuntimeConfig(states.encoder.get(), config);
 }
 
+TEST(AudioEncoderOpusTest, InvokeAudioNetworkAdaptorOnReceivedOverhead) {
+  auto states = CreateCodec(2);
+  states.encoder->EnableAudioNetworkAdaptor("", nullptr);
+
+  auto config = CreateEncoderRuntimeConfig();
+  EXPECT_CALL(**states.mock_audio_network_adaptor, GetEncoderRuntimeConfig())
+      .WillOnce(Return(config));
+
+  // Since using mock audio network adaptor, any overhead is fine.
+  constexpr size_t kOverhead = 64;
+  EXPECT_CALL(**states.mock_audio_network_adaptor, SetOverhead(kOverhead));
+  states.encoder->OnReceivedOverhead(kOverhead);
+
+  CheckEncoderRuntimeConfig(states.encoder.get(), config);
+}
+
 TEST(AudioEncoderOpusTest,
      PacketLossFractionSmoothedOnSetUplinkPacketLossFraction) {
   auto states = CreateCodec(2);
@@ -343,4 +361,64 @@ TEST(AudioEncoderOpusTest,
   EXPECT_FLOAT_EQ(0.05f, states.encoder->packet_loss_rate());
 }
 
+TEST(AudioEncoderOpusTest, DoNotInvokeSetTargetBitrateIfOverheadUnknown) {
+  test::ScopedFieldTrials override_field_trials(
+      "WebRTC-SendSideBwe-WithOverhead/Enabled/");
+
+  auto states = CreateCodec(2);
+
+  states.encoder->OnReceivedTargetAudioBitrate(kDefaultOpusSettings.rate * 2);
+
+  // Since |OnReceivedOverhead| has not been called, the codec bitrate should
+  // not change.
+  EXPECT_EQ(kDefaultOpusSettings.rate, states.encoder->GetTargetBitrate());
+}
+
+TEST(AudioEncoderOpusTest, OverheadRemovedFromTargetAudioBitrate) {
+  test::ScopedFieldTrials override_field_trials(
+      "WebRTC-SendSideBwe-WithOverhead/Enabled/");
+
+  auto states = CreateCodec(2);
+
+  constexpr size_t kOverheadBytesPerPacket = 64;
+  states.encoder->OnReceivedOverhead(kOverheadBytesPerPacket);
+
+  constexpr int kTargetBitrateBps = 40000;
+  states.encoder->OnReceivedTargetAudioBitrate(kTargetBitrateBps);
+
+  int packet_rate = rtc::CheckedDivExact(48000, kDefaultOpusSettings.pacsize);
+  EXPECT_EQ(kTargetBitrateBps -
+                8 * static_cast<int>(kOverheadBytesPerPacket) * packet_rate,
+            states.encoder->GetTargetBitrate());
+}
+
+TEST(AudioEncoderOpusTest, BitrateBounded) {
+  test::ScopedFieldTrials override_field_trials(
+      "WebRTC-SendSideBwe-WithOverhead/Enabled/");
+
+  constexpr int kMinBitrateBps = 500;
+  constexpr int kMaxBitrateBps = 512000;
+
+  auto states = CreateCodec(2);
+
+  constexpr size_t kOverheadBytesPerPacket = 64;
+  states.encoder->OnReceivedOverhead(kOverheadBytesPerPacket);
+
+  int packet_rate = rtc::CheckedDivExact(48000, kDefaultOpusSettings.pacsize);
+
+  // Set a target rate that is smaller than |kMinBitrateBps| when overhead is
+  // subtracted. The eventual codec rate should be bounded by |kMinBitrateBps|.
+  int target_bitrate =
+      kOverheadBytesPerPacket * 8 * packet_rate + kMinBitrateBps - 1;
+  states.encoder->OnReceivedTargetAudioBitrate(target_bitrate);
+  EXPECT_EQ(kMinBitrateBps, states.encoder->GetTargetBitrate());
+
+  // Set a target rate that is greater than |kMaxBitrateBps| when overhead is
+  // subtracted. The eventual codec rate should be bounded by |kMaxBitrateBps|.
+  target_bitrate =
+      kOverheadBytesPerPacket * 8 * packet_rate + kMaxBitrateBps + 1;
+  states.encoder->OnReceivedTargetAudioBitrate(target_bitrate);
+  EXPECT_EQ(kMaxBitrateBps, states.encoder->GetTargetBitrate());
+}
+
 }  // namespace webrtc