Pull out the PostFilter to its own NonlinearBeamformer API

webrtc/modules/audio_processing/audio_processing_impl.cc

Index: webrtc/modules/audio_processing/audio_processing_impl.cc
diff --git a/webrtc/modules/audio_processing/audio_processing_impl.cc b/webrtc/modules/audio_processing/audio_processing_impl.cc
index e75b3280346c7fc7120ead6b7d90d1f932b6dffb..055f1400bfde9ba9ecdb7c22706cf86be6453982 100644
--- a/webrtc/modules/audio_processing/audio_processing_impl.cc
+++ b/webrtc/modules/audio_processing/audio_processing_impl.cc
@@ -127,10 +127,10 @@ struct AudioProcessingImpl::ApmPublicSubmodules {
 };
 
 struct AudioProcessingImpl::ApmPrivateSubmodules {
-  explicit ApmPrivateSubmodules(Beamformer<float>* beamformer)
+  explicit ApmPrivateSubmodules(NonlinearBeamformer* beamformer)
       : beamformer(beamformer) {}
   // Accessed internally from capture or during initialization
-  std::unique_ptr<Beamformer<float>> beamformer;
+  std::unique_ptr<NonlinearBeamformer> beamformer;
   std::unique_ptr<AgcManagerDirect> agc_manager;
 };
 
@@ -144,7 +144,7 @@ AudioProcessing* AudioProcessing::Create(const Config& config) {
 }
 
 AudioProcessing* AudioProcessing::Create(const Config& config,
-                                         Beamformer<float>* beamformer) {
+                                         NonlinearBeamformer* beamformer) {
   AudioProcessingImpl* apm = new AudioProcessingImpl(config, beamformer);
   if (apm->Initialize() != kNoError) {
     delete apm;
@@ -158,7 +158,7 @@ AudioProcessingImpl::AudioProcessingImpl(const Config& config)
     : AudioProcessingImpl(config, nullptr) {}
 
 AudioProcessingImpl::AudioProcessingImpl(const Config& config,
-                                         Beamformer<float>* beamformer)
+                                         NonlinearBeamformer* beamformer)
     : public_submodules_(new ApmPublicSubmodules()),
       private_submodules_(new ApmPrivateSubmodules(beamformer)),
       constants_(config.Get<ExperimentalAgc>().startup_min_volume,
@@ -686,8 +686,8 @@ int AudioProcessingImpl::ProcessStreamLocked() {
   }
 
   if (capture_nonlocked_.beamformer_enabled) {
-    private_submodules_->beamformer->ProcessChunk(*ca->split_data_f(),
-                                                  ca->split_data_f());
+    private_submodules_->beamformer->AnalyzeChunk(*ca->split_data_f());
+    // Discards all channels by the leftmost one.
     ca->set_num_channels(1);

[peah-webrtc, 2016/06/23 22:02:40]

The handling of the number of channels is a bit messy.

As it is now, all the pipeline supports multichannel signals (maybe not in
practice, but at least in theory).

Would it not make sense to here set the number of channels equal to the desired
number of output channels? I.e.:
formats_.api_format.output_stream().num_channels()?

As it is now, that format is overridden when the beamformer is activated which
is not that nice. It may have been necessary to do it like that before this CL,
but now the pipeline supports multichannel processing which would motivate
changing this.

WDYT?

[aluebs-webrtc, 2016/06/24 03:00:54]

That makes sense, but it should be a different CL. It has nothing to do with
pulling out the PostFilter from the Beamformer.

   }
 
@@ -729,6 +729,10 @@ int AudioProcessingImpl::ProcessStreamLocked() {
   RETURN_ON_ERR(public_submodules_->echo_control_mobile->ProcessCaptureAudio(
       ca, stream_delay_ms()));
 
+  if (capture_nonlocked_.beamformer_enabled) {
+    private_submodules_->beamformer->PostFilter(ca->split_data_f());
+  }
+
   public_submodules_->voice_detection->ProcessCaptureAudio(ca);
 
   if (constants_.use_experimental_agc &&
@@ -1214,7 +1218,7 @@ void AudioProcessingImpl::InitializeBeamformer() {
   if (capture_nonlocked_.beamformer_enabled) {
     if (!private_submodules_->beamformer) {
       private_submodules_->beamformer.reset(new NonlinearBeamformer(
-          capture_.array_geometry, capture_.target_direction));
+          capture_.array_geometry, 1u, capture_.target_direction));
     }
     private_submodules_->beamformer->Initialize(kChunkSizeMs,
                                                 capture_nonlocked_.split_rate);