Update/modify the activation of multi-channel processing in APM

This CL
-Updates the multi-channel processing activation flags to match the
 the intended use in WebRTC.
-Makes sure that the APM in the audio processor complies to properly
run capture-side multi-channel processing.

Note: This CL can only land once the WebRTC CL
https://webrtc-review.googlesource.com/c/src/+/160707
has been landed and imported into Chromium.

Bug: webrtc:10859
Change-Id: Ied2b185d36e43187d90b5d608243702ec929ec1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1937030
Commit-Queue: Per Åhgren <peah@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Olga Sharonova <olka@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719944}

media/webrtc/audio_processor.cc

@@ -29,6 +29,11 @@ namespace media {
 
 namespace {
 
+bool UseMultiChannelCaptureProcessing() {
+  return base::FeatureList::IsEnabled(
+      features::kWebRtcEnableCaptureMultiChannelApm);
+}
+
 constexpr int kBuffersPerSecond = 100;  // 10 ms per buffer.
 
 }  // namespace
@@ -46,7 +51,9 @@ AudioProcessor::AudioProcessor(const AudioParameters& audio_parameters,
     : audio_parameters_(audio_parameters),
       settings_(settings),
       output_bus_(AudioBus::Create(audio_parameters_)),
-      audio_delay_stats_reporter_(kBuffersPerSecond) {
+      audio_delay_stats_reporter_(kBuffersPerSecond),
+      use_capture_multi_channel_processing_(
+          UseMultiChannelCaptureProcessing()) {
   DCHECK(audio_parameters.IsValid());
   DCHECK_EQ(audio_parameters_.GetBufferDuration(),
             base::TimeDelta::FromMilliseconds(10));
@@ -232,7 +239,9 @@ void AudioProcessor::InitializeAPM() {
   webrtc::AudioProcessing::Config apm_config = audio_processing_->GetConfig();
 
   // APM audio pipeline setup.
-  apm_config.pipeline.experimental_multi_channel = true;
+  apm_config.pipeline.multi_channel_render = true;
+  apm_config.pipeline.multi_channel_capture =
+      use_capture_multi_channel_processing_;
 
   // Typing detection setup.
   if (settings_.typing_detection) {

media/webrtc/audio_processor.h

@@ -110,6 +110,9 @@ class COMPONENT_EXPORT(MEDIA_WEBRTC) AudioProcessor final
   // thread.
   std::unique_ptr<rtc::TaskQueue> worker_queue_;
 
+  // Flag indicating whether capture multi channel processing should be active.
+  const bool use_capture_multi_channel_processing_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioProcessor);
 };
 

third_party/blink/renderer/modules/mediastream/media_stream_audio_processor.cc

@@ -61,6 +61,11 @@ namespace {
 
 using webrtc::AudioProcessing;
 
+bool UseMultiChannelCaptureProcessing() {
+  return base::FeatureList::IsEnabled(
+      features::kWebRtcEnableCaptureMultiChannelApm);
+}
+
 constexpr int kAudioProcessingNumberOfChannels = 1;
 constexpr int kBuffersPerSecond = 100;  // 10 ms per buffer.
 
@@ -234,7 +239,9 @@ MediaStreamAudioProcessor::MediaStreamAudioProcessor(
       audio_mirroring_(false),
       typing_detected_(false),
       aec_dump_agent_impl_(AecDumpAgentImpl::Create(this)),
-      stopped_(false) {
+      stopped_(false),
+      use_capture_multi_channel_processing_(
+          UseMultiChannelCaptureProcessing()) {
   DCHECK(main_thread_runner_);
   DETACH_FROM_THREAD(capture_thread_checker_);
   DETACH_FROM_THREAD(render_thread_checker_);
@@ -556,7 +563,9 @@ void MediaStreamAudioProcessor::InitializeAudioProcessingModule(
   }
 
   webrtc::AudioProcessing::Config apm_config = audio_processing_->GetConfig();
-  apm_config.pipeline.experimental_multi_channel = true;
+  apm_config.pipeline.multi_channel_render = true;
+  apm_config.pipeline.multi_channel_capture =
+      use_capture_multi_channel_processing_;
 
   base::Optional<double> gain_control_compression_gain_db;
   blink::PopulateApmConfig(&apm_config, properties,
@@ -617,9 +626,7 @@ void MediaStreamAudioProcessor::InitializeCaptureFifo(
                                      : input_format.sample_rate();
 
   media::ChannelLayout output_channel_layout;
-  if (!audio_processing_ ||
-      base::FeatureList::IsEnabled(
-          features::kWebRtcEnableCaptureMultiChannelApm)) {
+  if (!audio_processing_ || use_capture_multi_channel_processing_) {
     output_channel_layout = input_format.channel_layout();
   } else {
     output_channel_layout =

third_party/blink/renderer/modules/mediastream/media_stream_audio_processor.h

@@ -213,6 +213,9 @@ class MODULES_EXPORT MediaStreamAudioProcessor
   size_t apm_playout_error_code_log_count_ = 0;
   size_t large_delay_log_count_ = 0;
 
+  // Flag indicating whether capture multi channel processing should be active.
+  const bool use_capture_multi_channel_processing_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaStreamAudioProcessor);
 };