Merge "MediaPlayerService: Remove unnecessary zero writes to AudioSink" into mnc-dev

                me, buffer->raw, buffer->size, me->mCallbackCookie,

                me, buffer->raw, buffer->size, me->mCallbackCookie,

                CB_EVENT_FILL_BUFFER);

                CB_EVENT_FILL_BUFFER);

        if ((me->mFlags & AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD) == 0 &&

        // Log when no data is returned from the callback.

            actualSize == 0 && buffer->size > 0 && me->mNextOutput == NULL) {

        // (1) We may have no data (especially with network streaming sources).

            // We've reached EOS but the audio track is not stopped yet,

        // (2) We may have reached the EOS and the audio track is not stopped yet.

            // keep playing silence.

        // Note that AwesomePlayer/AudioPlayer will only return zero size when it reaches the EOS.

        // NuPlayerRenderer will return zero when it doesn't have data (it doesn't block to fill).

        //

        // This is a benign busy-wait, with the next data request generated 10 ms or more later;

        // nevertheless for power reasons, we don't want to see too many of these.

            memset(buffer->raw, 0, buffer->size);

        ALOGV_IF(actualSize == 0 && buffer->size > 0, "callbackwrapper: empty buffer returned");

            actualSize = buffer->size;

        }

        me->mBytesWritten += actualSize;  // benign race with reader.

        buffer->size = actualSize;

        buffer->size = actualSize;

        } break;

        } break;

    case AudioTrack::EVENT_STREAM_END:

    case AudioTrack::EVENT_STREAM_END:

        // currently only occurs for offloaded callbacks

        ALOGV("callbackwrapper: deliver EVENT_STREAM_END");

        ALOGV("callbackwrapper: deliver EVENT_STREAM_END");

        (*me->mCallback)(me, NULL /* buffer */, 0 /* size */,

        (*me->mCallback)(me, NULL /* buffer */, 0 /* size */,

                me->mCallbackCookie, CB_EVENT_STREAM_END);

                me->mCallbackCookie, CB_EVENT_STREAM_END);

        break;

        break;

    case AudioTrack::EVENT_UNDERRUN:

    case AudioTrack::EVENT_UNDERRUN:

        // This occurs when there is no data available, typically occurring

        // This occurs when there is no data available, typically

        // when there is a failure to supply data to the AudioTrack.  It can also

        // when there is a failure to supply data to the AudioTrack.  It can also

        // occur in non-offloaded mode when the audio device comes out of standby.

        // occur in non-offloaded mode when the audio device comes out of standby.

        //

        //

        // If you see this at the start of playback, there probably was a glitch.

        // If an AudioTrack underruns it outputs silence. Since this happens suddenly

        // it may sound like an audible pop or glitch.

        //

        // The underrun event is sent once per track underrun; the condition is reset

        // when more data is sent to the AudioTrack.

        ALOGI("callbackwrapper: EVENT_UNDERRUN (discarded)");

        ALOGI("callbackwrapper: EVENT_UNDERRUN (discarded)");

        break;

        break;