Feed audio constraints over to WebRtcLocalAudioTrack

content/renderer/media/webrtc_local_audio_track.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/webrtc_local_audio_track.h"
 
 #include "content/renderer/media/webrtc_audio_capturer.h"
 #include "content/renderer/media/webrtc_audio_capturer_sink_owner.h"
 #include "third_party/libjingle/source/talk/media/base/audiorenderer.h"
 
 namespace content {
 
 static const char kAudioTrackKind[] = "audio";
 
+namespace {
+
+using webrtc::MediaConstraintsInterface;
+
+// This helper function checks if any audio constraints are set that require

[henrika (OOO until Aug 14), 2013/08/26 11:34:55]

Can we set an audio constraint which does not require audio processing?

[tommi (sloooow) - chröme, 2013/08/27 10:58:22]

yes it is conceivable that constraints be supported that don't require
processing (thinking out loud, stuff like sample rate).  Explicitly setting
audio constraints to False is another way to specify constraints that do not
require audio processing :)

+// audio processing to be applied.  Right now this is a big, single switch for
+// all of the properties, but in the future they'll be handled one by one.
+bool NeedsAudioProcessing(
+    const webrtc::MediaConstraintsInterface* constraints) {
+  if (!constraints)
+    return false;
+
+  static const char* kAudioProcessingProperties[] = {
+    MediaConstraintsInterface::kEchoCancellation,
+    MediaConstraintsInterface::kExperimentalEchoCancellation,
+    MediaConstraintsInterface::kAutoGainControl,
+    MediaConstraintsInterface::kExperimentalAutoGainControl,
+    MediaConstraintsInterface::kNoiseSuppression,
+    MediaConstraintsInterface::kHighpassFilter,
+  };
+
+  for (size_t i = 0; i < arraysize(kAudioProcessingProperties); ++i) {
+    bool value = false;
+    if (webrtc::FindConstraint(constraints, kAudioProcessingProperties[i],
+                               &value, NULL) &&
+        value) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+}  // namespace.
+
 scoped_refptr<WebRtcLocalAudioTrack> WebRtcLocalAudioTrack::Create(
     const std::string& id,
     const scoped_refptr<WebRtcAudioCapturer>& capturer,
-    webrtc::AudioSourceInterface* track_source) {
+    webrtc::AudioSourceInterface* track_source,
+    const webrtc::MediaConstraintsInterface* constraints) {
   talk_base::RefCountedObject<WebRtcLocalAudioTrack>* track =
       new talk_base::RefCountedObject<WebRtcLocalAudioTrack>(
-          id, capturer, track_source);
+          id, capturer, track_source, constraints);
   return track;
 }
 
 WebRtcLocalAudioTrack::WebRtcLocalAudioTrack(
     const std::string& label,
     const scoped_refptr<WebRtcAudioCapturer>& capturer,
-    webrtc::AudioSourceInterface* track_source)
+    webrtc::AudioSourceInterface* track_source,
+    const webrtc::MediaConstraintsInterface* constraints)
     : webrtc::MediaStreamTrack<webrtc::AudioTrackInterface>(label),
       capturer_(capturer),
       track_source_(track_source),
-      need_audio_processing_(!capturer->device_id().empty()) {
+      need_audio_processing_(NeedsAudioProcessing(constraints)) {
   // The capturer with a valid device id is using microphone as source,
   // and APM (AudioProcessingModule) is turned on only for microphone data.
   DCHECK(capturer.get());
   DVLOG(1) << "WebRtcLocalAudioTrack::WebRtcLocalAudioTrack()";
+
+  // TODO(xians): Remove this workaround. It is currently here to maintain

[henrika (OOO until Aug 14), 2013/08/26 11:34:55]

Possibly add link to crbug here.

[tommi (sloooow) - chröme, 2013/08/27 10:58:22]

Done.

+  // backwards compatibility with the previous implementations and apps where
+  // no constraints are specified for audio but we've still enabled audio
+  // processing.
+  if (!need_audio_processing_ && !capturer->device_id().empty()) {
+    DLOG(WARNING) << "Enabling audio processing despite lack of constraints.";
+    need_audio_processing_ = true;
+  }
 }
 
 WebRtcLocalAudioTrack::~WebRtcLocalAudioTrack() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DVLOG(1) << "WebRtcLocalAudioTrack::~WebRtcLocalAudioTrack()";
   // Users might not call Stop() on the track.
   Stop();
 }
 
 void WebRtcLocalAudioTrack::CaptureData(const int16* audio_data,
@@ skipping 142 matching lines @@
     base::AutoLock auto_lock(lock_);
     sinks = sinks_;
     capturer_ = NULL;
   }
 
   for (SinkList::const_iterator it = sinks.begin(); it != sinks.end(); ++it)
     (*it)->Reset();
 }
 
 }  // namespace content