FFMPEG Plugin: Refactor out loading next video chunk.
- Main reason for refactoring was to increase readability of _DecodeNextVideoFrame() by simplifying it. Refactoring was tested successfully for no functional change with mpeg2_decoder_test. - Reindented the method definition in the header file so that the new method _LoadNextVideoChunkIfNeededAndUpdateStartTime() fits into 80 chars per line. Reindentdation is applied to methods only as the member variables have no space left for reindentation. - Update documentation accordingly. - Fix wording of audio part to audio path. - No functional change intended.
This commit is contained in:
Colin Günther
parent
2d83b8419c
commit
6defcb6c6d
@ -142,7 +142,7 @@ AVCodecDecoder::~AVCodecDecoder()
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avcodec_close(fContext);
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free(fVideoChunkBuffer);
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// TODO: Replace with fChunkBuffer, once audio part is
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// TODO: Replace with fChunkBuffer, once audio path is
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// responsible for freeing the chunk buffer, too.
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free(fDecodedData);
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@ -265,7 +265,7 @@ AVCodecDecoder::SeekedTo(int64 frame, bigtime_t time)
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// Flush internal buffers as well.
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free(fVideoChunkBuffer);
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// TODO: Replace with fChunkBuffer, once audio part is
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// TODO: Replace with fChunkBuffer, once audio path is
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// responsible for freeing the chunk buffer, too.
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fChunkBuffer = NULL;
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fChunkBufferOffset = 0;
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@ -687,7 +687,7 @@ AVCodecDecoder::_DecodeVideo(void* outBuffer, int64* outFrameCount,
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}
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/*! \brief Decode next video frame
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/*! \brief Decodes next video frame.
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We decode exactly one video frame into fDecodedData. To achieve this goal,
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we might need to request several chunks of encoded data resulting in a
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@ -702,7 +702,7 @@ AVCodecDecoder::_DecodeVideo(void* outBuffer, int64* outFrameCount,
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To every decoded video frame there is a media_header populated in
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fHeader, containing the corresponding video frame properties.
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Normally every decoded video frame has a start_time field populated in the
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associated fHeader, that determines the presentation time of the frame.
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This relationship will only hold true, when each data chunk that is
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@ -725,8 +725,8 @@ AVCodecDecoder::_DecodeVideo(void* outBuffer, int64* outFrameCount,
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More over the fOutputFrameRate variable is updated for every decoded video
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frame.
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On first call, the member variables fSwsContext / fFormatConversionFunc
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are initialized.
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On first call the member variables fSwsContext / fFormatConversionFunc are
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initialized.
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\returns B_OK when we successfully decoded one video frame
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\returns B_LAST_BUFFER_ERROR when there are no more video frames available.
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@ -739,77 +739,16 @@ AVCodecDecoder::_DecodeNextVideoFrame()
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assert(fTempPacket.size >= 0);
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while (true) {
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media_header chunkMediaHeader;
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status_t loadingChunkStatus
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= _LoadNextVideoChunkIfNeededAndUpdateStartTime();
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if (fTempPacket.size == 0) {
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// Our packet buffer is empty, so fill it now.
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const void* chunkBuffer = NULL;
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status_t getNextChunkStatus = GetNextChunk(&chunkBuffer,
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&fChunkBufferSize, &chunkMediaHeader);
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switch (getNextChunkStatus) {
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case B_OK:
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break;
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if (loadingChunkStatus == B_LAST_BUFFER_ERROR)
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return _FlushOneVideoFrameFromDecoderBuffer();
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case B_LAST_BUFFER_ERROR:
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return _FlushOneVideoFrameFromDecoderBuffer();
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default:
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TRACE("AVCodecDecoder::_DecodeNextVideoFrame(): error from"
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" GetNextChunk(): %s\n", strerror(err));
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return getNextChunkStatus;
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}
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free(fVideoChunkBuffer);
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// Free any previously used chunk buffer first
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// TODO: Replace with fChunkBuffer, once audio part is
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// responsible for freeing the chunk buffer, too.
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fVideoChunkBuffer
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= static_cast<uint8_t*>(const_cast<void*>(chunkBuffer));
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// TODO: Replace fVideoChunkBuffer with fChunkBuffer, once
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// audio part is responsible for freeing the chunk buffer, too.
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status_t chunkBufferPaddingStatus
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= _AddInputBufferPaddingToVideoChunkBuffer();
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if (chunkBufferPaddingStatus != B_OK)
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return chunkBufferPaddingStatus;
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fTempPacket.data = fVideoChunkBuffer;
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// TODO: Replace with fChunkBuffer, once audio part is
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// responsible for freeing the chunk buffer, too.
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fTempPacket.size = fChunkBufferSize;
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fContext->reordered_opaque = chunkMediaHeader.start_time;
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// Let FFMPEG handle the relationship between start_time and
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// decoded video frame.
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//
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// Explanation:
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// The received chunk buffer may not contain the next video
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// frame to be decoded, due to frame reordering (e.g. MPEG1/2
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// provides encoded video frames in a different order than the
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// decoded video frame).
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//
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// FIXME: Research how to establish a meaningful relationship
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// between start_time and decoded video frame when the received
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// chunk buffer contains partial video frames. Maybe some data
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// formats contain time stamps (ake pts / dts fields) that can
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// be evaluated by FFMPEG. But as long as I don't have such
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// video data to test it, it makes no sense to implement it.
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//
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// FIXME: Implement tracking start_time of video frames
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// originating in data chunks that encode more than one video
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// frame at a time. In that case on would increment the
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// start_time for each consecutive frame of such a data chunk
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// (like it is done for audio frame decoding). But as long as
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// I don't have such video data to test it, it makes no sense
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// to implement it.
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#ifdef LOG_STREAM_TO_FILE
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if (sDumpedPackets < 100) {
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sStreamLogFile.Write(chunkBuffer, fChunkBufferSize);
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printf("wrote %ld bytes\n", fChunkBufferSize);
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sDumpedPackets++;
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} else if (sDumpedPackets == 100)
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sStreamLogFile.Unset();
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#endif
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if (loadingChunkStatus != B_OK) {
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TRACE("AVCodecDecoder::_DecodeNextVideoFrame(): error from "
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"GetNextChunk(): %s\n", strerror(err));
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return loadingChunkStatus;
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}
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#if DO_PROFILING
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@ -822,9 +761,9 @@ AVCodecDecoder::_DecodeNextVideoFrame()
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// packet buffer is allowed to contain incomplete frames so we are
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// required to buffer the packets between different calls to
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// _DecodeNextVideoFrame().
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int gotPicture = 0;
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int gotVideoFrame = 0;
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int decodedDataSizeInBytes = avcodec_decode_video2(fContext,
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fRawDecodedPicture, &gotPicture, &fTempPacket);
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fRawDecodedPicture, &gotVideoFrame, &fTempPacket);
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if (decodedDataSizeInBytes < 0) {
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TRACE("[v] AVCodecDecoder: ignoring error in decoding frame %lld:"
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" %d\n", fFrame, len);
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@ -839,8 +778,8 @@ AVCodecDecoder::_DecodeNextVideoFrame()
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fTempPacket.size -= decodedDataSizeInBytes;
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fTempPacket.data += decodedDataSizeInBytes;
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bool gotNoPictureYet = gotPicture == 0;
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if (gotNoPictureYet) {
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bool gotNoVideoFrame = gotVideoFrame == 0;
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if (gotNoVideoFrame) {
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TRACE("frame %lld - no picture yet, decodedDataSizeInBytes: %d, "
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"chunk size: %ld\n", fFrame, decodedDataSizeInBytes,
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fChunkBufferSize);
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@ -882,6 +821,91 @@ AVCodecDecoder::_DecodeNextVideoFrame()
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}
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/*! \brief Loads the next video chunk into fVideoChunkBuffer and assigns it to
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fTempPacket accordingly only if fTempPacket is empty. Updates fContext
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with the start time of the new data chunk.
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\returns B_OK
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1. meaning: Next video chunk is loaded and fContext is updated.
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2. meaning: No need to load and update anything. Proceed as usual.
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\returns B_LAST_BUFFER_ERROR No more video chunks available.
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fVideoChunkBuffer, fTempPacket and fContext are left untouched.
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\returns Other errors Caller should bail out because fVideoChunkBuffer,
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fTempPacket and fContext are in unknown states. Normal operation cannot
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be guaranteed.
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*/
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status_t
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AVCodecDecoder::_LoadNextVideoChunkIfNeededAndUpdateStartTime()
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{
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// TODO: Rename fVideoChunkBuffer to fChunkBuffer, once the audio path is
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// responsible for releasing the chunk buffer, too.
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if (fTempPacket.size > 0)
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return B_OK;
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const void* chunkBuffer = NULL;
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size_t chunkBufferSize = 0;
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// In the case that GetNextChunk() returns an error fChunkBufferSize
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// should be left untouched.
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media_header chunkMediaHeader;
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status_t getNextChunkStatus = GetNextChunk(&chunkBuffer,
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&chunkBufferSize, &chunkMediaHeader);
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if (getNextChunkStatus != B_OK)
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return getNextChunkStatus;
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fChunkBufferSize = chunkBufferSize;
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free(fVideoChunkBuffer);
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// Free any previously used chunk buffer first
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fVideoChunkBuffer
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= static_cast<uint8_t*>(const_cast<void*>(chunkBuffer));
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status_t chunkBufferPaddingStatus
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= _AddInputBufferPaddingToVideoChunkBuffer();
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if (chunkBufferPaddingStatus != B_OK)
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return chunkBufferPaddingStatus;
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fTempPacket.data = fVideoChunkBuffer;
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fTempPacket.size = fChunkBufferSize;
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fContext->reordered_opaque = chunkMediaHeader.start_time;
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// Let FFMPEG handle the relationship between start_time and
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// decoded video frame.
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//
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// Explanation:
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// The received chunk buffer may not contain the next video
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// frame to be decoded, due to frame reordering (e.g. MPEG1/2
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// provides encoded video frames in a different order than the
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// decoded video frame).
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//
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// FIXME: Research how to establish a meaningful relationship
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// between start_time and decoded video frame when the received
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// chunk buffer contains partial video frames. Maybe some data
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// formats contain time stamps (ake pts / dts fields) that can
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// be evaluated by FFMPEG. But as long as I don't have such
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// video data to test it, it makes no sense to implement it.
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//
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// FIXME: Implement tracking start_time of video frames
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// originating in data chunks that encode more than one video
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// frame at a time. In that case on would increment the
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// start_time for each consecutive frame of such a data chunk
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// (like it is done for audio frame decoding). But as long as
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// I don't have such video data to test it, it makes no sense
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// to implement it.
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#ifdef LOG_STREAM_TO_FILE
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if (sDumpedPackets < 100) {
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sStreamLogFile.Write(chunkBuffer, fChunkBufferSize);
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printf("wrote %ld bytes\n", fChunkBufferSize);
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sDumpedPackets++;
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} else if (sDumpedPackets == 100)
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sStreamLogFile.Unset();
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#endif
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return B_OK;
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}
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/*! \brief Adds a "safety net" of additional memory to fVideoChunkBuffer as
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required by FFMPEG for input buffers to video decoders.
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@ -899,7 +923,7 @@ AVCodecDecoder::_DecodeNextVideoFrame()
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status_t
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AVCodecDecoder::_AddInputBufferPaddingToVideoChunkBuffer()
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{
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// TODO: Rename fVideoChunkBuffer to fChunkBuffer, once the audio part is
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// TODO: Rename fVideoChunkBuffer to fChunkBuffer, once the audio path is
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// responsible for releasing the chunk buffer, too.
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fVideoChunkBuffer
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= static_cast<uint8_t*>(realloc(static_cast<void*>(fVideoChunkBuffer),
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@ -961,13 +985,14 @@ AVCodecDecoder::_FlushOneVideoFrameFromDecoderBuffer()
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fTempPacket.data = NULL;
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fTempPacket.size = 0;
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int gotPicture = 0;
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avcodec_decode_video2(fContext, fRawDecodedPicture, &gotPicture,
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int gotVideoFrame = 0;
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avcodec_decode_video2(fContext, fRawDecodedPicture, &gotVideoFrame,
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&fTempPacket);
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// We are only interested in complete frames now, so ignore the return
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// value.
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if (gotPicture == 0) {
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bool gotNoVideoFrame = gotVideoFrame == 0;
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if (gotNoVideoFrame) {
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// video buffer is flushed successfully
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return B_LAST_BUFFER_ERROR;
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}
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@ -28,52 +28,51 @@ extern "C" {
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class AVCodecDecoder : public Decoder {
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public:
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AVCodecDecoder();
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AVCodecDecoder();
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virtual ~AVCodecDecoder();
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virtual ~AVCodecDecoder();
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virtual void GetCodecInfo(media_codec_info* mci);
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virtual void GetCodecInfo(media_codec_info* mci);
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virtual status_t Setup(media_format* ioEncodedFormat,
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const void* infoBuffer, size_t infoSize);
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virtual status_t Setup(media_format* ioEncodedFormat,
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const void* infoBuffer, size_t infoSize);
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virtual status_t NegotiateOutputFormat(
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media_format* inOutFormat);
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virtual status_t NegotiateOutputFormat(media_format* inOutFormat);
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virtual status_t Decode(void* outBuffer, int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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virtual status_t Decode(void* outBuffer, int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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virtual status_t SeekedTo(int64 trame, bigtime_t time);
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virtual status_t SeekedTo(int64 trame, bigtime_t time);
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private:
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void _ResetTempPacket();
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void _ResetTempPacket();
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status_t _NegotiateAudioOutputFormat(
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media_format* inOutFormat);
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status_t _NegotiateAudioOutputFormat(media_format* inOutFormat);
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status_t _NegotiateVideoOutputFormat(
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media_format* inOutFormat);
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status_t _NegotiateVideoOutputFormat(media_format* inOutFormat);
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status_t _DecodeAudio(void* outBuffer,
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int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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status_t _DecodeAudio(void* outBuffer, int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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status_t _DecodeVideo(void* outBuffer,
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int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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status_t _DecodeNextVideoFrame();
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status_t _AddInputBufferPaddingToVideoChunkBuffer();
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// TODO: Remove the "Video" word once
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// the audio part is responsible for
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// freeing the chunk buffer, too.
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void _HandleNewVideoFrameAndUpdateSystemState();
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status_t _FlushOneVideoFrameFromDecoderBuffer();
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void _UpdateMediaHeaderForVideoFrame();
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void _DeinterlaceAndColorConvertVideoFrame();
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status_t _DecodeVideo(void* outBuffer, int64* outFrameCount,
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media_header* mediaHeader,
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media_decode_info* info);
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status_t _DecodeNextVideoFrame();
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status_t _LoadNextVideoChunkIfNeededAndUpdateStartTime();
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// TODO: Remove the "Video" word once
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// the audio path is responsible for
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// freeing the chunk buffer, too.
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status_t _AddInputBufferPaddingToVideoChunkBuffer();
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// TODO: Remove the "Video" word once
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// the audio path is responsible for
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// freeing the chunk buffer, too.
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void _HandleNewVideoFrameAndUpdateSystemState();
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status_t _FlushOneVideoFrameFromDecoderBuffer();
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void _UpdateMediaHeaderForVideoFrame();
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void _DeinterlaceAndColorConvertVideoFrame();
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media_header fHeader;
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@ -112,7 +111,7 @@ private:
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const void* fChunkBuffer;
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uint8_t* fVideoChunkBuffer;
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// TODO: Remove and use fChunkBuffer again
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// (with type uint8_t*) once the audio part is
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// (with type uint8_t*) once the audio path is
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// responsible for freeing the chunk buffer,
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// too.
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int32 fChunkBufferOffset;
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