HEVC代码追踪（十三）:解码之decode

2019-04-15 15:19发布

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// ==================================================================================================================== // Public member functions // ==================================================================================================================== /** - create internal class - initialize internal class - until the end of the bitstream, call decoding function in TDecTop class - delete allocated buffers - destroy internal class . */ Void TAppDecTop::decode() { Int poc; TComList* pcListPic = NULL; ifstream bitstreamFile(m_pchBitstreamFile, ifstream::in | ifstream::binary); if (!bitstreamFile) { fprintf(stderr, " failed to open bitstream file `%s' for reading ", m_pchBitstreamFile); exit(EXIT_FAILURE); } InputByteStream bytestream(bitstreamFile); // create & initialize internal classes xCreateDecLib(); xInitDecLib (); m_iPOCLastDisplay += m_iSkipFrame; // set the last displayed POC correctly for skip forward. // main decoder loop Bool openedReconFile = false; // reconstruction file not yet opened. (must be performed after SPS is seen) Bool loopFiltered = false; while (!!bitstreamFile) { /* location serves to work around a design fault in the decoder, whereby * the process of reading a new slice that is the first slice of a new frame * requires the TDecTop::decode() method to be called again with the same * nal unit. */ streampos location = bitstreamFile.tellg(); AnnexBStats stats = AnnexBStats(); vector nalUnit; InputNALUnit nalu; byteStreamNALUnit(bytestream, nalUnit, stats); // call actual decoding function Bool bNewPicture = false; if (nalUnit.empty()) { /* this can happen if the following occur: * - empty input file * - two back-to-back start_code_prefixes * - start_code_prefix immediately followed by EOF */ fprintf(stderr, "Warning: Attempt to decode an empty NAL unit "); } else { read(nalu, nalUnit); if( (m_iMaxTemporalLayer >= 0 && nalu.m_temporalId > m_iMaxTemporalLayer) || !isNaluWithinTargetDecLayerIdSet(&nalu) ) { bNewPicture = false; } else { bNewPicture = m_cTDecTop.decode(nalu, m_iSkipFrame, m_iPOCLastDisplay); if (bNewPicture) { bitstreamFile.clear(); /* location points to the current nalunit payload[1] due to the * need for the annexB parser to read three extra bytes. * [1] except for the first NAL unit in the file * (but bNewPicture doesn't happen then) */ bitstreamFile.seekg(location-streamoff(3)); bytestream.reset(); } } } if (bNewPicture || !bitstreamFile || nalu.m_nalUnitType == NAL_UNIT_EOS) { if (!loopFiltered || bitstreamFile) { m_cTDecTop.executeLoopFilters(poc, pcListPic); } loopFiltered = (nalu.m_nalUnitType == NAL_UNIT_EOS); } #if !FIX_WRITING_OUTPUT #if SETTING_NO_OUT_PIC_PRIOR if (bNewPicture && m_cTDecTop.getIsNoOutputPriorPics()) { m_cTDecTop.checkNoOutputPriorPics( pcListPic ); } #endif #endif if( pcListPic ) { if ( m_pchReconFile && !openedReconFile ) { if (!m_outputBitDepthY) { m_outputBitDepthY = g_bitDepthY; } if (!m_outputBitDepthC) { m_outputBitDepthC = g_bitDepthC; } m_cTVideoIOYuvReconFile.open( m_pchReconFile, true, m_outputBitDepthY, m_outputBitDepthC, g_bitDepthY, g_bitDepthC ); // write mode openedReconFile = true; } #if FIX_WRITING_OUTPUT // write reconstruction to file if( bNewPicture ) { xWriteOutput( pcListPic, nalu.m_temporalId ); } #if SETTING_NO_OUT_PIC_PRIOR if ( (bNewPicture || nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_CRA) && m_cTDecTop.getNoOutputPriorPicsFlag() ) { m_cTDecTop.checkNoOutputPriorPics( pcListPic ); m_cTDecTop.setNoOutputPriorPicsFlag (false); } #endif #endif if ( bNewPicture && ( nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_IDR_W_RADL || nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_IDR_N_LP || nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_BLA_N_LP || nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_BLA_W_RADL || nalu.m_nalUnitType == NAL_UNIT_CODED_SLICE_BLA_W_LP ) ) { xFlushOutput( pcListPic ); } if (nalu.m_nalUnitType == NAL_UNIT_EOS) { #if FIX_OUTPUT_EOS xWriteOutput( pcListPic, nalu.m_temporalId ); #else xFlushOutput( pcListPic ); #endif } // write reconstruction to file -- for additional bumping as defined in C.5.2.3 #if FIX_WRITING_OUTPUT if(!bNewPicture && nalu.m_nalUnitType >= NAL_UNIT_CODED_SLICE_TRAIL_N && nalu.m_nalUnitType <= NAL_UNIT_RESERVED_VCL31) #else if(bNewPicture) #endif { xWriteOutput( pcListPic, nalu.m_temporalId ); } } } xFlushOutput( pcListPic ); // delete buffers m_cTDecTop.deletePicBuffer(); // destroy internal classes xDestroyDecLib(); }



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