Merge "Audio ENCODING_IEC61937: enforce use of CHANNEL_OUT_STEREO" into nyc-dev

am: 566e721

* commit '566e7212ab5ba29de5e1a3446f029c3aca998258':
  Audio ENCODING_IEC61937: enforce use of CHANNEL_OUT_STEREO

media/java/android/media/AudioFormat.java

@@ -256,6 +256,11 @@ public final class AudioFormat implements Parcelable {
     public static final int ENCODING_AAC_HE_V2 = 12;
     /** Audio data format: compressed audio wrapped in PCM for HDMI
      * or S/PDIF passthrough.
+     * IEC61937 uses a stereo stream of 16-bit samples as the wrapper.
+     * So the channel mask for the track must be {@link #CHANNEL_OUT_STEREO}.
+     * Data should be written to the stream in a short[] array.
+     * If the data is written in a byte[] array then there may be endian problems
+     * on some platforms when converting to short internally.
      */
     public static final int ENCODING_IEC61937 = 13;
 

media/java/android/media/AudioTrack.java

@@ -806,6 +806,15 @@ public class AudioTrack implements AudioRouting
         }
         mSampleRate = sampleRateInHz;
 
+        // IEC61937 is based on stereo. We could coerce it to stereo.
+        // But the application needs to know the stream is stereo so that
+        // it is encoded and played correctly. So better to just reject it.
+        if (audioFormat == AudioFormat.ENCODING_IEC61937
+                && channelConfig != AudioFormat.CHANNEL_OUT_STEREO) {
+            throw new IllegalArgumentException(
+                    "ENCODING_IEC61937 must be configured as CHANNEL_OUT_STEREO");
+        }
+
         //--------------
         // channel config
         mChannelConfiguration = channelConfig;