Shulou(Shulou.com)06/02 Report--

Codec coding transmission process is how, many novices are not very clear about this, in order to help you solve this problem, the following editor will explain in detail for you, people with this need can come to learn, I hope you can gain something.

The SurfaceMediaSource::read () lock controls reading the buffer from the IGraphicBufferConsumer, when the graphic generates data

Wait while Overrun

While (mStarted & & mNumPendingBuffers = = mMaxAcquiredBufferCount) {

MMediaBuffersAvailableCondition.wait (mMutex)

}

After MediaPuller got the buffer,

Status_t err = mSource- > read (& mbuf)

Notify- > setInt32 ("what", kWhatAccessUnit)

Notify- > setBuffer ("accessUnit", accessUnit)

Notify- > post ()

Converter receives CHECK_EQ (what, MediaPuller::kWhatAccessUnit)

After

MInputBufferQueue.push_back (accessUnit)

FeedEncoderInputBuffers ()

Copy buffer data to mEncoderInputBuffers of codec in Converter::feedEncoderInputBuffers ()

Wait for the copy through this while loop

While (! mInputBufferQueue.empty () & &! mAvailEncoderInputIndices.empty ()) {

Memcpy (mEncoderInputBuffers.itemAt (bufferIndex)-> data ()

Buffer- > data ()

Buffer- > size ()

Status_t err = mEncoder- > queueInputBuffer (

BufferIndex, 0, (buffer = = NULL)? 0: buffer- > size ()

TimeUs, flags)

5. The above process passes mainly the shared memory buffer_handle_t, when the codec completes the ACodec::BaseState::onOMXEmptyBufferDone

/ / We're in "store-metadata-in-buffers" mode, the underlying

/ / OMX component had access to data that's implicitly refcounted

/ / by this "MediaBuffer" object. Now that the OMX component has

/ / told us that it's done with the input buffer, we can decrement

/ / the mediaBuffer's reference count.

Info- > mData- > setMediaBufferBase (NULL)

To inform SurfaceMediaSource::signalBufferReturned () to let graphic consumer actually release

MConsumer- > releaseBuffer ()

Stack information

# 06 pc 000f4583 / system/lib/libstagefright.so (android::SurfaceMediaSource::signalBufferReturned (android::MediaBuffer*) + 38)

# 07 pc 000f45a5 / system/lib/libstagefright.so (non-virtual thunk to android::SurfaceMediaSource::signalBufferReturned (android::MediaBuffer*) + 4)

# 08 pc 0000b011 / system/lib/libstagefright_foundation.so (android::ABuffer::setMediaBufferBase (android::MediaBufferBase*) + 16)

# 09 pc 0008adeb / system/lib/libstagefright.so (android::ACodec::BaseState::onOMXEmptyBufferDone (unsigned int, int) + 78)

# 10 pc 0008aab5 / system/lib/libstagefright.so (android::ACodec::BaseState::onOMXMessage (android::sp const&) + 228)

# 11 pc 0008a731 / system/lib/libstagefright.so (android::ACodec::BaseState::onMessageReceived (android::sp const&) + 744)

# 12 pc 0008e779 / system/lib/libstagefright.so (android::ACodec::ExecutingState::onMessageReceived (android::sp const&) + 508)

# 13 pc 0000b5a1 / system/lib/libstagefright_foundation.so (android::AHierarchicalStateMachine::handleMessage (android::sp const&) + 64)

# 14 pc 0008a917 / system/lib/libstagefright.so (android::ACodec::BaseState::onOMXMessageList (android::sp const&) + 106)

# 15 pc 0008a5e7 / system/lib/libstagefright.so (android::ACodec::BaseState::onMessageReceived (android::sp const&) + 414)

# 16 pc 0008e779 / system/lib/libstagefright.so (android::ACodec::ExecutingState::onMessageReceived (android::sp const&) + 508)

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