stagefright 播放流程

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setDataSource_l(uri)

{

         mUri = uri;

}

准备

prepare_l()

{

         onPrepareAsyncEvent();

}

onPrepareAsyncEvent()

{

         DataSource dataSource = DataSource::CreateFromURI(mUri.string(), &mUriHeaders);

         {

                   source = new FileSource(uri + 7);

}

extractor = MediaExtractor::Create(

                dataSource, sniffedMIME.empty() ? NULL : sniffedMIME.c_str());

         {

                   ret = new MPEG4Extractor(source);

}

 

         source->sniff(&tmp, &confidence, &meta);

         {

                   *mimeType = MEDIA_MIMETYPE_CONTAINER_MPEG4;

             *confidence = 0.4f;

}

status_t err = setDataSource_l(extractor);

{

         setVideoSource(extractor->getTrack(i));

         {

                   mVideoTrack = source; MPEG4Source

}

         getTrack();

         {

return new MPEG4Source(

            track->meta, mDataSource, track->timescale, track->sampleTable);

                   mDataSoruce=FileSource;

}

}

 

initVideoDecoder();

initAudioDecoder();

finishAsyncPrepare_l();

}

initVideoDecoder()

{

         mVideoSource = OMXCodec::Create(

            mClient.interface(), mVideoTrack->getFormat(),

            false, // createEncoder

            mVideoTrack,

            NULL, flags, USE_SURFACE_ALLOC ? mNativeWindow : NULL);

         {

                   sp<OMXCodec> codec = new OMXCodec(

                    omx, node, quirks, flags,

                    createEncoder, mime, componentName,

                    source, nativeWindow);

                                               {

                                                        mOMX(omx);

                                                        mSource(source); mVideoTrack;

}

         }

         mVideoSource = codec;

         mVideoSource ->start(); è OMXCodec::start

}

OMXCodec::start()

{

mSource->start(params.get());=>MPEG4Source::start

{

         mGroup = new MediaBufferGroup;

mGroup->add_buffer(new MediaBuffer(max_size));

mSrcBuffer = new uint8_t[max_size];

}

         Init()

         {

                   mOMX->sendCommand(mNode, OMX_CommandStateSet, OMX_StateIdle);

err = allocateBuffers();

}

}

 

播放

Playe_l

{

         postVideoEvent_l();

onVideoEvent();

mVideoSource->read(&mVideoBuffer, &options);

}

OMXCodec::read()

{

Vector<BufferInfo> *buffers = &mPortBuffers[kPortIndexInput];

drainInputBuffer();

err = mSource->read(&srcBuffer, &options);

{

         num_bytes_read = mDataSource->readAt(offset, mSrcBuffer, size);

}

}