void NuPlayer::Renderer::onQueueBuffer(const sp<AMessage> &msg) {
    int32_t audio;
    CHECK(msg->findInt32("audio", &audio));

    if (dropBufferIfStale(audio, msg)) {
        return;
    }

    if (audio) {
        mHasAudio = true; //音频
    } else {
        mHasVideo = true; //视频
    }

    if (mHasVideo) {
        if (mVideoScheduler == NULL) {
            mVideoScheduler = new VideoFrameScheduler();  //视频渲染调整
           mVideoScheduler->init();
        }
    }

    sp<ABuffer> buffer;
    CHECK(msg->findBuffer("buffer", &buffer));

    sp<AMessage> notifyConsumed;
    CHECK(msg->findMessage("notifyConsumed", &notifyConsumed));

    QueueEntry entry;
    entry.mBuffer = buffer;
    entry.mNotifyConsumed = notifyConsumed;
    entry.mOffset = 0;
   entry.mFinalResult = OK;
   entry.mBufferOrdinal = ++mTotalBuffersQueued;

   if (audio) {
       Mutex::Autolock autoLock(mLock);
        mAudioQueue.push_back(entry);
        postDrainAudioQueue_l(); //刷新音频
    } else {
        mVideoQueue.push_back(entry);
       postDrainVideoQueue(); //刷新视频
   }

    Mutex::Autolock autoLock(mLock);
    if (!mSyncQueues || mAudioQueue.empty() || mVideoQueue.empty()) {
        return;
    }

    sp<ABuffer> firstAudioBuffer = (*mAudioQueue.begin()).mBuffer;
    sp<ABuffer> firstVideoBuffer = (*mVideoQueue.begin()).mBuffer;

    if (firstAudioBuffer == NULL || firstVideoBuffer == NULL) {
        // EOS signalled on either queue.
        syncQueuesDone_l();
        return;
    }

   int64_t firstAudioTimeUs;
    int64_t firstVideoTimeUs;
    CHECK(firstAudioBuffer->meta()
            ->findInt64("timeUs", &firstAudioTimeUs));
    CHECK(firstVideoBuffer->meta()
            ->findInt64("timeUs", &firstVideoTimeUs));

    int64_t diff = firstVideoTimeUs - firstAudioTimeUs;

    ALOGV("queueDiff = %.2f secs", diff / 1E6);

    if (diff > 100000ll) {
        // Audio data starts More than 0.1 secs before video.
       // Drop some audio.

       (*mAudioQueue.begin()).mNotifyConsumed->post();
       mAudioQueue.erase(mAudioQueue.begin());
        return;
    }

    syncQueuesDone_l();
}