查看Android MediaCodec trace的源代码 Android MediaCodec trace 0

* MediaPlayer calling flow
 MediaPlayer mp = new MediaPlayer();
 1.        mp.setDataSource(filePath);
 2.        mp.setDisplay(MediaFrameworkTest.mSurfaceView.getHolder());
 3.        mp.prepare(); //获取和解码媒体数据
 4.        mp.start();
 5.        FillBuffer
 6.        EmptyBuffer

1.  setDataSource(filePath)

    <source lang="c">
<MediaPlayerBase> mPlayer = Create form (playerType of source);
	//      => new NuPlayerDriver(pid) {
				mLooper->setName("NuPlayerDriver Looper")->start(PRIORITY_AUDIO);
				mPlayer = new NuPlayer(pid);
			}
	//绑定Extractor、omx、codec2服务的death监听，
	//mPlayer->setDataSource(dataSource)
</source>
	
2. setDisplay(SurfaceHolder sh)
<source lang="c">
{
   mSurfaceHolder = sh;
   _setVideoSurface(sh.getSurface());-->
   {
       MediaPlayer.cpp {
	  sp<IGraphicBufferProducer> new_st =  surface->getIGraphicBufferProducer();
	  MediaPlayerService mp->setVideoSurfaceTexture(new_st);
       }
       MediaPlayerService::Client::setVideoSurfaceTexture(<IGraphicBufferProducer>& bufferProducer)
       sp<ANativeWindow> anw;
      if (bufferProducer != NULL) {
        anw = new Surface(bufferProducer, true /* controlledByApp */);
        status_t err = native_window_api_connect(anw.get(),
                NATIVE_WINDOW_API_MEDIA);

        p->setVideoSurfaceTexture(bufferProducer);
        mConnectedWindow = anw; //decoder
    }
}

</source>

3. prepare
<source lang="c">
	NuPlayer::GenericSource::onPrepareAsync(){
	dataSource = DataSourceFactory::CreateFromURI(uri) or  new FileSource(mFd, mOffset, mLength);
	<IMediaExtractor> ex = mediaExService->makeExtractor() =>
	                       MediaExtractorFactory::CreateFromService(localSource, mime); =>
						   creator = sniff(source, &confidence, &meta, &freeMeta, plugin, &creatorVersion);==>
						   find best creator from ExtractorPlugin gPlugins list.

</source>
4. start
	<source lang="c">
void NuPlayer::start()==> (new AMessage(kWhatStart, this))->post();
	NuPlayer::onMessageReceived(const sp<AMessage> &msg) {  case kWhatStart: onStart();}
	=>  NuPlayer::onStart(int64_t startPositionUs, MediaPlayerSeekMode mode) 
	=> 	mSource->start();
		hasVideo = (mSource->getFormat(false /* audio */) != NULL);
	    mRenderer = new Renderer(mAudioSink, mMediaClock, notify, flags);
		mRendererLooper = new ALooper;
		mRendererLooper->start(false, false, ANDROID_PRIORITY_AUDIO);
		mRenderer->setPlaybackSettings(mPlaybackSettings);
		mRendererLooper->registerHandler(mRenderer);
		mRenderer->setVideoFrameRate(rate);
		postScanSources()=> (new AMessage(kWhatScanSources, this))->post(); => NuPlayer::onMessageReceived( kWhatScanSources) {
			instantiateDecoder(false, &mVideoDecoder)
			{	
				notify = new AMessage(kWhatVideoNotify, this);
				*decoder = new Decoder(notify, mSource, mPID, mUID, mRenderer, mSurface, mCCDecoder);
				format->setInt32("auto-frc", 1);//  enable FRC if high-quality AV sync is requested
				(*decoder)->init();
				(*decoder)->configure(format);
				//buffer
				<ABuffer> inputBufs = (*decoder)->getInputBuffers();
				for each buffer in inputBufs[i],
					mbuf = new MediaBuffer(buffer->data(), buffer->size());
					mediaBufs.push(mbuf);
				mSource->setBuffers(audio, mediaBufs);
			}
	    
		}
	NuPlayer::Decoder::onConfigure(const sp<AMessage> &format)
	{
		 mComponentName = format->findString("mime")="audio/ video/xxx"+"decoder";
		 mCodec = MediaCodec::CreateByType(mCodecLooper, mime, false /* encoder */, NULL /* err */, mPid);
		 // disconnect from surface as MediaCodec will reconnect
		 mCodec->configure(format, mSurface, NULL /* crypto */, 0 /* flags */);
		 rememberCodecSpecificData(format);
		mCodec->getOutputFormat(&mOutputFormat);
		mCodec->getInputFormat(&mInputFormat));
		//find width and height from mOutputFormat()
		mCodec->setCallback(reply);
		mCodec->start();
		releaseAndResetMediaBuffers();
	}
	mCodec->initiateAllocateComponent(format);=> msg->setWhat(kWhatAllocateComponent);=> msg->setWhat(kWhatAllocateComponent);
	ACodec::UninitializedState::onAllocateComponent(msg) {
		OMXClient client;
		client.connect();
		<IOMX> omx = client.interface();
		 OMXCodec::findMatchingCodecs(mime, encoder, &matchingCodecs);
		 omx->allocateNode(componentName.c_str(), observer, &node);
		 mCodec->mNotify->("CodecBase::kWhatComponentAllocated")
	}
	

</source>

5. Decoder input:
[[文件:fillbuffer.png]]
<source lang="c">
	MediaCodec::onInputBufferAvailable()
	NuPlayer::Decoder::handleAnInputBuffer(…)
	NuPlayer::Decoder::onInputBufferFetched(…)
	OMX::emptyBuffer(…)，
	//decode
	SoftOMXComponent::notifyEmptyBufferDone(…)
	OMX::OnEmptyBufferDone(…)
	ACodec::BaseState::onOMXEmptyBufferDone(…)

</source>	
6. Decoder output
[[文件:emptybuffer.png]]
ref:https://blog.csdn.net/yanbixing123/article/details/88937106?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase
ref: https://blog.csdn.net/yanbixing123/article/details/88925903#comments

<source lang="c">
	ACodec::ExecutingState::submitOutputBuffers()
	ACodec::BaseState::postFillThisBuffer(…)
	OMX:: fillBuffer (…)
	SimpleSoftOMXComponent::fillThisBuffer(…)
	//write decoded output
	SoftOMXComponent::notifyFillBufferDone(…)
	OMX:: OnFillBufferDone (…)
	ACodec::BaseState:: onOMXFillBufferDone (…)；
	NuPlayer::Decoder::handleAnOutputBuffer(…)


</source>