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Commit d9e58713 authored by Jean-Michel Trivi's avatar Jean-Michel Trivi
Browse files

Verify AudioTrack only uses a valid multichannel configuration 

Enforce the same rules as for HDMI output:
- FL/FR must be present
- paired channels must be used in pairs (e.g. no rear left
   without rear right)

Bug 6392126

Change-Id: I0a39e474dcf509cb7eabd8edd1f0e44852d72b51
parent 2d97a70f

media/java/android/media/AudioTrack.java

+32 −1
Original line number Diff line number Diff line
@@ -401,7 +401,7 @@ public class AudioTrack 
            mChannels = AudioFormat.CHANNEL_OUT_STEREO;

            break;

        default:

            if ((channelConfig & SUPPORTED_OUT_CHANNELS) != channelConfig) {

            if (!isMultichannelConfigSupported(channelConfig)) {

                // input channel configuration features unsupported channels

                mChannelCount = 0;

                mChannels = AudioFormat.CHANNEL_INVALID;
@@ -438,6 +438,37 @@ public class AudioTrack 
        }

    }



    /**

     * Convenience method to check that the channel configuration (a.k.a channel mask) is supported

     * @param channelConfig the mask to validate

     * @return false if the AudioTrack can't be used with such a mask

     */

    private static boolean isMultichannelConfigSupported(int channelConfig) {

        // check for unsupported channels

        if ((channelConfig & SUPPORTED_OUT_CHANNELS) != channelConfig) {

            Log.e(TAG, "Channel configuration features unsupported channels");

            return false;

        }

        // check for unsupported multichannel combinations:

        // - FL/FR must be present

        // - L/R channels must be paired (e.g. no single L channel)

        final int frontPair =

                AudioFormat.CHANNEL_OUT_FRONT_LEFT | AudioFormat.CHANNEL_OUT_FRONT_RIGHT;

        if ((channelConfig & frontPair) != frontPair) {

                Log.e(TAG, "Front channels must be present in multichannel configurations");

                return false;

        }

        final int backPair =

                AudioFormat.CHANNEL_OUT_BACK_LEFT | AudioFormat.CHANNEL_OUT_BACK_RIGHT;

        if ((channelConfig & backPair) != 0) {

            if ((channelConfig & backPair) != backPair) {

                Log.e(TAG, "Rear channels can't be used independently");

                return false;

            }

        }

        return true;

    }





    // Convenience method for the contructor's audio buffer size check.

    // preconditions: