Bug 971528 - Allow stereo capture in AudioCallbackDriver. r=padenot

* * *
[mq]: graph-driver-comments

MozReview-Commit-ID: JnU3opk8X5K
* * *
[mq]: tmp

MozReview-Commit-ID: 73CtZw4CRG

--HG--
extra : rebase_source : bca0932ccffc6348260039fc7ec829245a9b2236

dom/media/GraphDriver.cpp

@@ -662,10 +662,19 @@ AudioCallbackDriver::Init()
     latency_frames = std::max((uint32_t) 512, latency_frames);
   }
 
-
   input = output;
-  input.channels = mInputChannels; // change to support optional stereo capture
-  input.layout = CUBEB_LAYOUT_MONO;
+  input.channels = mInputChannels;
+  input.layout = CUBEB_LAYOUT_UNDEFINED;
+
+#ifdef MOZ_WEBRTC
+  if (mGraphImpl->mInputWanted) {
+    StaticMutexAutoLock lock(AudioInputCubeb::Mutex());
+    uint32_t maxInputChannels = 0;
+    if (AudioInputCubeb::GetDeviceMaxChannels(mGraphImpl->mInputDeviceID, maxInputChannels) == 0) {
+      input.channels = mInputChannels = maxInputChannels;
+    }
+  }
+#endif
 
   cubeb_stream* stream = nullptr;
   CubebUtils::AudioDeviceID input_id = nullptr, output_id = nullptr;

dom/media/webrtc/MediaEngineWebRTC.h

@@ -212,6 +212,7 @@ public:
         aIndex = mDefaultDevice;
       }
     }
+    MOZ_ASSERT(mDeviceIndexes);
     if (aIndex < 0 || aIndex >= (int) mDeviceIndexes->Length()) {
       return -1;
     }
@@ -267,6 +268,20 @@ public:
     return 0;
   }
 
+  static int GetDeviceMaxChannels(int aDeviceIndex, uint32_t& aChannels)
+  {
+#ifdef MOZ_WIDGET_ANDROID
+    aChannels = 1;
+#else
+    int32_t devindex = DeviceIndex(aDeviceIndex);
+    if (!mDevices || devindex < 0) {
+      return 1;
+    }
+    aChannels = mDevices->device[devindex]->max_channels;
+#endif
+    return 0;
+  }
+
   void StartRecording(SourceMediaStream *aStream, AudioDataListener *aListener)
   {
 #ifdef MOZ_WIDGET_ANDROID