diff options
Diffstat (limited to 'libMpegTPDec/src/tpdec_adts.cpp')
| -rw-r--r-- | libMpegTPDec/src/tpdec_adts.cpp | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/libMpegTPDec/src/tpdec_adts.cpp b/libMpegTPDec/src/tpdec_adts.cpp new file mode 100644 index 0000000..e64ae82 --- /dev/null +++ b/libMpegTPDec/src/tpdec_adts.cpp @@ -0,0 +1,326 @@ +/***************************** MPEG-4 AAC Decoder ************************** + + (C) Copyright Fraunhofer IIS (2004) + All Rights Reserved + + Please be advised that this software and/or program delivery is + Confidential Information of Fraunhofer and subject to and covered by the + + Fraunhofer IIS Software Evaluation Agreement + between Google Inc. and Fraunhofer + effective and in full force since March 1, 2012. + + You may use this software and/or program only under the terms and + conditions described in the above mentioned Fraunhofer IIS Software + Evaluation Agreement. Any other and/or further use requires a separate agreement. + + + $Id$ + Author(s): Josef Hoepfl + Description: ADTS interface + + This software and/or program is protected by copyright law and international + treaties. Any reproduction or distribution of this software and/or program, + or any portion of it, may result in severe civil and criminal penalties, and + will be prosecuted to the maximum extent possible under law. + +******************************************************************************/ + +#include "tpdec_adts.h" + + +#include "FDK_bitstream.h" + + + +void adtsRead_CrcInit(HANDLE_ADTS pAdts) /*!< pointer to adts crc info stucture */ +{ + FDKcrcInit(&pAdts->crcInfo, 0x8005, 0xFFFF, 16); +} + +int adtsRead_CrcStartReg( + HANDLE_ADTS pAdts, /*!< pointer to adts stucture */ + HANDLE_FDK_BITSTREAM hBs, /*!< handle to current bit buffer structure */ + int mBits /*!< number of bits in crc region */ + ) +{ + if (pAdts->bs.protection_absent) { + return 0; + } + + return ( FDKcrcStartReg(&pAdts->crcInfo, hBs, mBits) ); + +} + +void adtsRead_CrcEndReg( + HANDLE_ADTS pAdts, /*!< pointer to adts crc info stucture */ + HANDLE_FDK_BITSTREAM hBs, /*!< handle to current bit buffer structure */ + int reg /*!< crc region */ + ) +{ + if (pAdts->bs.protection_absent == 0) + { + FDKcrcEndReg(&pAdts->crcInfo, hBs, reg); + } +} + +TRANSPORTDEC_ERROR adtsRead_CrcCheck( HANDLE_ADTS pAdts ) +{ + TRANSPORTDEC_ERROR ErrorStatus = TRANSPORTDEC_OK; + USHORT crc; + + if (pAdts->bs.protection_absent) + return TRANSPORTDEC_OK; + + crc = FDKcrcGetCRC(&pAdts->crcInfo); + if (crc != pAdts->crcReadValue) + { + return (TRANSPORTDEC_CRC_ERROR); + } + + return (ErrorStatus); +} + + + +#define Adts_Length_SyncWord 12 +#define Adts_Length_Id 1 +#define Adts_Length_Layer 2 +#define Adts_Length_ProtectionAbsent 1 +#define Adts_Length_Profile 2 +#define Adts_Length_SamplingFrequencyIndex 4 +#define Adts_Length_PrivateBit 1 +#define Adts_Length_ChannelConfiguration 3 +#define Adts_Length_OriginalCopy 1 +#define Adts_Length_Home 1 +#define Adts_Length_CopyrightIdentificationBit 1 +#define Adts_Length_CopyrightIdentificationStart 1 +#define Adts_Length_FrameLength 13 +#define Adts_Length_BufferFullness 11 +#define Adts_Length_NumberOfRawDataBlocksInFrame 2 +#define Adts_Length_CrcCheck 16 + +TRANSPORTDEC_ERROR adtsRead_DecodeHeader( + HANDLE_ADTS pAdts, + CSAudioSpecificConfig *pAsc, + HANDLE_FDK_BITSTREAM hBs, + const INT ignoreBufferFullness + ) +{ + INT crcReg; + + INT valBits; + INT cmp_buffer_fullness; + int i, adtsHeaderLength; + + STRUCT_ADTS_BS bs; + +#ifdef TP_PCE_ENABLE + CProgramConfig oldPce; + /* Store the old PCE temporarily. Maybe we'll need it later if we + have channelConfig=0 and no PCE in this frame. */ + FDKmemcpy(&oldPce, &pAsc->m_progrConfigElement, sizeof(CProgramConfig)); +#endif + + valBits = FDKgetValidBits(hBs); + + /* adts_fixed_header */ + bs.mpeg_id = FDKreadBits(hBs, Adts_Length_Id); + bs.layer = FDKreadBits(hBs, Adts_Length_Layer); + bs.protection_absent = FDKreadBits(hBs, Adts_Length_ProtectionAbsent); + bs.profile = FDKreadBits(hBs, Adts_Length_Profile); + bs.sample_freq_index = FDKreadBits(hBs, Adts_Length_SamplingFrequencyIndex); + bs.private_bit = FDKreadBits(hBs, Adts_Length_PrivateBit); + bs.channel_config = FDKreadBits(hBs, Adts_Length_ChannelConfiguration); + bs.original = FDKreadBits(hBs, Adts_Length_OriginalCopy); + bs.home = FDKreadBits(hBs, Adts_Length_Home); + + /* adts_variable_header */ + bs.copyright_id = FDKreadBits(hBs, Adts_Length_CopyrightIdentificationBit); + bs.copyright_start = FDKreadBits(hBs, Adts_Length_CopyrightIdentificationStart); + bs.frame_length = FDKreadBits(hBs, Adts_Length_FrameLength); + bs.adts_fullness = FDKreadBits(hBs, Adts_Length_BufferFullness); + bs.num_raw_blocks = FDKreadBits(hBs, Adts_Length_NumberOfRawDataBlocksInFrame); + bs.num_pce_bits = 0; + + adtsHeaderLength = ADTS_HEADERLENGTH; + + if (!bs.protection_absent) { + FDKcrcReset(&pAdts->crcInfo); + FDKpushBack(hBs, 56); /* complete fixed and variable header! */ + crcReg = FDKcrcStartReg(&pAdts->crcInfo, hBs, 0); + FDKpushFor(hBs, 56); + } + + if (! bs.protection_absent && bs.num_raw_blocks>0) { + for (i=0; i<bs.num_raw_blocks; i++) { + pAdts->rawDataBlockDist[i] = (USHORT)FDKreadBits(hBs, 16); + adtsHeaderLength += 16; + } + /* Change raw data blocks to delta values */ + pAdts->rawDataBlockDist[bs.num_raw_blocks] = bs.frame_length - 7 - bs.num_raw_blocks*2 - 2 ; + for (i=bs.num_raw_blocks; i>0; i--) { + pAdts->rawDataBlockDist[i] -= pAdts->rawDataBlockDist[i-1]; + } + } + + /* adts_error_check */ + if (!bs.protection_absent) + { + USHORT crc_check; + + FDKcrcEndReg(&pAdts->crcInfo, hBs, crcReg); + crc_check = FDKreadBits(hBs, Adts_Length_CrcCheck); + adtsHeaderLength += Adts_Length_CrcCheck; + + pAdts->crcReadValue = crc_check; + /* Check header CRC in case of multiple raw data blocks */ + if (bs.num_raw_blocks > 0) { + if (pAdts->crcReadValue != FDKcrcGetCRC(&pAdts->crcInfo)) { + return TRANSPORTDEC_CRC_ERROR; + } + /* Reset CRC for the upcoming raw_data_block() */ + FDKcrcReset(&pAdts->crcInfo); + } + } + + + /* check if valid header */ + if ( + (bs.layer != 0) || // we only support MPEG ADTS + (bs.sample_freq_index >= 13) // we only support 96kHz - 7350kHz + ) { + FDKpushFor(hBs, bs.frame_length * 8); // try again one frame later + return TRANSPORTDEC_UNSUPPORTED_FORMAT; + } + + /* special treatment of id-bit */ + if ( (bs.mpeg_id == 0) && (pAdts->decoderCanDoMpeg4 == 0) ) + { + /* MPEG-2 decoder cannot play MPEG-4 bitstreams */ + + + FDKpushFor(hBs, bs.frame_length * 8); // try again one frame later + return TRANSPORTDEC_UNSUPPORTED_FORMAT; + } + + if (!ignoreBufferFullness) + { + cmp_buffer_fullness = bs.frame_length*8 + bs.adts_fullness*32*getNumberOfEffectiveChannels(bs.channel_config); + + + /* Evaluate buffer fullness */ + if (bs.adts_fullness != 0x7FF) + { + if (pAdts->BufferFullnesStartFlag) + { + if ( valBits < cmp_buffer_fullness ) + { + /* Condition for start of decoding is not fulfilled */ + + /* The current frame will not be decoded */ + FDKpushBack(hBs, adtsHeaderLength); + + if ( (cmp_buffer_fullness+adtsHeaderLength) > ((TRANSPORTDEC_INBUF_SIZE<<3)-7) ) { + return TRANSPORTDEC_SYNC_ERROR; + } else { + return TRANSPORTDEC_NOT_ENOUGH_BITS; + } + } + else + { + pAdts->BufferFullnesStartFlag = 0; + } + } + } + } + + + /* Get info from ADTS header */ + AudioSpecificConfig_Init(pAsc); + pAsc->m_aot = (AUDIO_OBJECT_TYPE)(bs.profile + 1); + pAsc->m_samplingFrequencyIndex = bs.sample_freq_index; + pAsc->m_samplingFrequency = SamplingRateTable[bs.sample_freq_index]; + pAsc->m_channelConfiguration = bs.channel_config; + pAsc->m_samplesPerFrame = 1024; + +#ifdef TP_PCE_ENABLE + if (bs.channel_config == 0) + { + int pceBits = 0; + UINT alignAnchor = FDKgetValidBits(hBs); + + if (FDKreadBits(hBs,3) == ID_PCE) { + /* Got luck! Parse the PCE */ + int crcReg; + crcReg = adtsRead_CrcStartReg(pAdts, hBs, 0); + + CProgramConfig_Read(&pAsc->m_progrConfigElement, hBs, alignAnchor); + + adtsRead_CrcEndReg(pAdts, hBs, crcReg); + pceBits = alignAnchor - FDKgetValidBits(hBs); + /* store the number of PCE bits */ + bs.num_pce_bits = pceBits; + } + else { + /* No PCE in this frame! Push back the ID tag bits. */ + FDKpushBack(hBs,3); + + /* Encoders do not have to write a PCE in each frame. + So if we already have a valid PCE we have to use it. */ + if ( oldPce.isValid + && (bs.sample_freq_index == pAdts->bs.sample_freq_index) /* we could compare the complete fixed header (bytes) here! */ + && (bs.channel_config == pAdts->bs.channel_config) /* == 0 */ + && (bs.mpeg_id == pAdts->bs.mpeg_id) ) + { /* Restore previous PCE which is still valid */ + FDKmemcpy(&pAsc->m_progrConfigElement, &oldPce, sizeof(CProgramConfig)); + } + else if (bs.mpeg_id == 0) { + /* If not it seems that we have a implicit channel configuration. + This mode is not allowed in the context of ISO/IEC 14496-3. + Skip this frame and try the next one. */ + FDKpushFor(hBs, (bs.frame_length<<3) - adtsHeaderLength - 3); + return TRANSPORTDEC_UNSUPPORTED_FORMAT; + } + /* else { + ISO/IEC 13818-7 implicit channel mapping is allowed. + So just open the box of chocolates to see what we got. + } */ + } + } +#endif /* TP_PCE_ENABLE */ + + /* Copy bit stream data struct to persistent memory now, once we passed all sanity checks above. */ + FDKmemcpy(&pAdts->bs, &bs, sizeof(STRUCT_ADTS_BS)); + + return TRANSPORTDEC_OK; +} + +int adtsRead_GetRawDataBlockLength( + HANDLE_ADTS pAdts, + INT blockNum + ) +{ + int length; + + if (pAdts->bs.num_raw_blocks == 0) { + length = (pAdts->bs.frame_length - 7) << 3; /* aac_frame_length subtracted by the header size (7 bytes). */ + if (pAdts->bs.protection_absent == 0) + length -= 16; /* substract 16 bit CRC */ + } else { + if (pAdts->bs.protection_absent) { + length = -1; /* raw data block length is unknown */ + } else { + if (blockNum < 0 || blockNum > 3) { + return TRANSPORTDEC_INVALID_PARAMETER; + } + length = (pAdts->rawDataBlockDist[blockNum] << 3) - 16; + } + } + if (blockNum == 0) { + length -= pAdts->bs.num_pce_bits; + } + return length; +} + + |