/*---------------------------------------------------------------------------------------------
description: This function returns a bit from the bitstream according to
read direction. It is called very often, therefore it makes sense to inline it
(runtime).
-----------------------------------------------------------------------------------------------
input: - handle to FDK bitstream
- reference value marking start of bitfield
- pLeftStartOfSegment
- pRightStartOfSegment
- readDirection
-----------------------------------------------------------------------------------------------
return: - bit from bitstream
--------------------------------------------------------------------------------------------
*/
UINT HcrGetABitFromBitstream(HANDLE_FDK_BITSTREAM bs, const INT bsAnchor,
INT *pLeftStartOfSegment,
INT *pRightStartOfSegment, UCHAR readDirection) {
UINT bit;
INT readBitOffset;
if (readDirection == FROM_LEFT_TO_RIGHT) {
readBitOffset = (INT)FDKgetValidBits(bs) - bsAnchor + *pLeftStartOfSegment;
if (readBitOffset) {
FDKpushBiDirectional(bs, readBitOffset);
}
bit = FDKreadBits(bs, 1);
*pLeftStartOfSegment += 1;
} else {
readBitOffset = (INT)FDKgetValidBits(bs) - bsAnchor + *pRightStartOfSegment;
if (readBitOffset) {
FDKpushBiDirectional(bs, readBitOffset);
}
/* to be replaced with a brother function of FDKreadBits() */
bit = FDKreadBits(bs, 1);
FDKpushBack(bs, 2);
*pRightStartOfSegment -= 1;
}
return (bit);
}
TRANSPORTDEC_ERROR adifRead_DecodeHeader(
CAdifHeader *pAdifHeader,
CProgramConfig *pPce,
HANDLE_FDK_BITSTREAM bs
)
{
int i;
TRANSPORTDEC_ERROR ErrorStatus = TRANSPORTDEC_OK;
UINT startAnchor = FDKgetValidBits(bs);
if ((INT)startAnchor < MIN_ADIF_HEADERLENGTH) {
return (TRANSPORTDEC_NOT_ENOUGH_BITS);
}
if (FDKreadBits(bs,8) != 'A') {
return (TRANSPORTDEC_SYNC_ERROR);
}
if (FDKreadBits(bs,8) != 'D') {
return (TRANSPORTDEC_SYNC_ERROR);
}
if (FDKreadBits(bs,8) != 'I') {
return (TRANSPORTDEC_SYNC_ERROR);
}
if (FDKreadBits(bs,8) != 'F') {
return (TRANSPORTDEC_SYNC_ERROR);
}
if ( (pAdifHeader->CopyrightIdPresent = FDKreadBits(bs,1)) != 0 )
FDKpushBiDirectional(bs,72); /* CopyrightId */
pAdifHeader->OriginalCopy = FDKreadBits(bs,1);
pAdifHeader->Home = FDKreadBits(bs,1);
pAdifHeader->BitstreamType = FDKreadBits(bs,1);
/* pAdifHeader->BitRate = FDKreadBits(bs, 23); */
pAdifHeader->BitRate = FDKreadBits(bs,16);
pAdifHeader->BitRate <<= 7;
pAdifHeader->BitRate |= FDKreadBits(bs,7);
pAdifHeader->NumProgramConfigElements = FDKreadBits(bs,4) + 1;
if (pAdifHeader->BitstreamType == 0) {
FDKpushBiDirectional(bs,20); /* adif_buffer_fullness */
}
/* Parse all PCEs but keep only one */
for (i=0; i < pAdifHeader->NumProgramConfigElements; i++)
{
CProgramConfig_Read(pPce, bs, startAnchor);
}
FDKbyteAlign(bs, startAnchor);
return (ErrorStatus);
}
UCHAR rvlcReadBitFromBitstream (HANDLE_FDK_BITSTREAM bs,
USHORT *pPosition,
UCHAR readDirection)
{
UINT bit;
INT readBitOffset = *pPosition-FDKgetBitCnt(bs);
if( readBitOffset ) {
FDKpushBiDirectional(bs, readBitOffset);
}
if (readDirection == FWD) {
bit = FDKreadBits(bs, 1);
*pPosition += 1;
} else {
/* to be replaced with a brother function of FDKreadBits() */
bit = FDKreadBits(bs, 1);
FDKpushBack(bs, 2);
*pPosition -= 1;
}
return (bit);
}
TRANSPORTDEC_ERROR transportDec_CrcCheck(HANDLE_TRANSPORTDEC pTp)
{
switch (pTp->transportFmt) {
case TT_MP4_ADTS:
if ( (pTp->parser.adts.bs.num_raw_blocks > 0) && (pTp->parser.adts.bs.protection_absent == 0) )
{
HANDLE_FDK_BITSTREAM hBs = &pTp->bitStream[0];
int bitDiff;
/* Calculate possible offset to CRC value. */
bitDiff = pTp->parser.adts.rawDataBlockDist[pTp->parser.adts.bs.num_raw_blocks-pTp->numberOfRawDataBlocks]<<3;
bitDiff -= pTp->globalFramePos - FDKgetValidBits(hBs) + 16;
FDKpushBiDirectional(hBs, bitDiff);
pTp->parser.adts.crcReadValue = FDKreadBits(hBs, 16);
}
return adtsRead_CrcCheck(&pTp->parser.adts);
default:
return TRANSPORTDEC_OK;
}
}
/**
* \brief adjust bit stream position and the end of an access unit.
* \param hTp transport decoder handle.
* \return error code.
*/
static
TRANSPORTDEC_ERROR transportDec_AdjustEndOfAccessUnit(HANDLE_TRANSPORTDEC hTp)
{
HANDLE_FDK_BITSTREAM hBs = &hTp->bitStream[0];
TRANSPORTDEC_ERROR err = TRANSPORTDEC_OK;
switch (hTp->transportFmt) {
case TT_MP4_LOAS:
case TT_MP4_LATM_MCP0:
case TT_MP4_LATM_MCP1:
if ( hTp->numberOfRawDataBlocks == 0 )
{
/* Check global frame length */
if (hTp->transportFmt == TT_MP4_LOAS && hTp->parser.latm.m_audioMuxLengthBytes > 0)
{
int loasOffset;
loasOffset = (hTp->parser.latm.m_audioMuxLengthBytes*8 + FDKgetValidBits(hBs)) - hTp->globalFramePos;
if (loasOffset != 0) {
FDKpushBiDirectional(hBs, loasOffset);
/* For ELD and other payloads there is an unknown amount of padding, so ignore unread bits, but
throw an error only if too many bits where read. */
if (loasOffset < 0) {
err = TRANSPORTDEC_PARSE_ERROR;
}
}
}
/* Do global LOAS/LATM audioMuxElement byte alignment */
FDKbyteAlign(hBs, hTp->globalFramePos);
}
break;
default:
break;
}
return err;
}
static
TRANSPORTDEC_ERROR synchronization(
HANDLE_TRANSPORTDEC hTp,
INT *pHeaderBits
)
{
TRANSPORTDEC_ERROR err = TRANSPORTDEC_OK, errFirstFrame = TRANSPORTDEC_OK;
HANDLE_FDK_BITSTREAM hBs = &hTp->bitStream[0];
INT syncLayerFrameBits = 0; /* Length of sync layer frame (i.e. LOAS) */
INT rawDataBlockLength = 0, rawDataBlockLengthPrevious;
INT totalBits;
INT headerBits = 0, headerBitsFirstFrame = 0, headerBitsPrevious;
INT numFramesTraversed = 0, fTraverseMoreFrames, fConfigFound = 0, startPos, startPosFirstFrame = -1;
INT numRawDataBlocksFirstFrame = 0, numRawDataBlocksPrevious, globalFramePosFirstFrame = 0, rawDataBlockLengthFirstFrame = 0;
INT ignoreBufferFullness = hTp->flags & (TPDEC_IGNORE_BUFFERFULLNESS|TPDEC_SYNCOK);
/* Synch parameters */
INT syncLength; /* Length of sync word in bits */
UINT syncWord; /* Sync word to be found */
UINT syncMask; /* Mask for sync word (for adding one bit, so comprising one bit less) */
C_ALLOC_SCRATCH_START(contextFirstFrame, transportdec_parser_t, 1);
totalBits = (INT)FDKgetValidBits(hBs);
if (totalBits <= 0) {
/* Return sync error, because this happens only in case of severly damaged bit streams.
Returning TRANSPORTDEC_NOT_ENOUGH_BITS here is very dangerous. */
/* numberOfRawDataBlocks must be always reset in case of sync errors. */
hTp->numberOfRawDataBlocks = 0;
goto bail;
}
fTraverseMoreFrames = (hTp->flags & (TPDEC_MINIMIZE_DELAY|TPDEC_EARLY_CONFIG)) && ! (hTp->flags & TPDEC_SYNCOK);
/* Set transport specific sync parameters */
switch (hTp->transportFmt) {
case TT_MP4_ADTS:
syncWord = ADTS_SYNCWORD;
syncLength = ADTS_SYNCLENGTH;
break;
case TT_MP4_LOAS:
syncWord = 0x2B7;
syncLength = 11;
break;
default:
syncWord = 0;
syncLength = 0;
break;
}
syncMask = (1<<syncLength)-1;
do {
INT bitsAvail = 0; /* Bits available in bitstream buffer */
INT checkLengthBits; /* Helper to check remaining bits and buffer boundaries */
UINT synch; /* Current sync word read from bitstream */
headerBitsPrevious = headerBits;
bitsAvail = (INT)FDKgetValidBits(hBs);
if (hTp->numberOfRawDataBlocks == 0) {
/* search synchword */
FDK_ASSERT( (bitsAvail % TPDEC_SYNCSKIP) == 0);
if ((bitsAvail-syncLength) < TPDEC_SYNCSKIP) {
err = TRANSPORTDEC_NOT_ENOUGH_BITS;
headerBits = 0;
} else {
synch = FDKreadBits(hBs, syncLength);
if ( !(hTp->flags & TPDEC_SYNCOK) ) {
for (; (bitsAvail-syncLength) >= TPDEC_SYNCSKIP; bitsAvail-=TPDEC_SYNCSKIP) {
if (synch == syncWord) {
break;
}
synch = ((synch << TPDEC_SYNCSKIP) & syncMask) | FDKreadBits(hBs, TPDEC_SYNCSKIP);
}
}
if (synch != syncWord) {
/* No correct syncword found. */
err = TRANSPORTDEC_SYNC_ERROR;
} else {
err = TRANSPORTDEC_OK;
}
headerBits = syncLength;
}
} else {
headerBits = 0;
}
/* Save previous raw data block data */
rawDataBlockLengthPrevious = rawDataBlockLength;
numRawDataBlocksPrevious = hTp->numberOfRawDataBlocks;
/* Parse transport header (raw data block granularity) */
startPos = FDKgetValidBits(hBs);
if (err == TRANSPORTDEC_OK )
{
switch (hTp->transportFmt) {
case TT_MP4_ADTS:
if (hTp->numberOfRawDataBlocks <= 0)
{
int errC;
/* Parse ADTS header */
err = adtsRead_DecodeHeader( &hTp->parser.adts, &hTp->asc[0], hBs, ignoreBufferFullness );
if (err != TRANSPORTDEC_OK) {
if (err != TRANSPORTDEC_NOT_ENOUGH_BITS) {
err = TRANSPORTDEC_SYNC_ERROR;
}
} else {
errC = hTp->callbacks.cbUpdateConfig(hTp->callbacks.cbUpdateConfigData, &hTp->asc[0]);
if (errC != 0) {
err = TRANSPORTDEC_SYNC_ERROR;
} else {
hTp->numberOfRawDataBlocks = hTp->parser.adts.bs.num_raw_blocks+1;
/* CAUTION: The PCE (if available) is declared to be a part of the header! */
hTp->globalFramePos = FDKgetValidBits(hBs) + hTp->parser.adts.bs.num_pce_bits;
}
}
}
else {
/* Reset CRC because the next bits are the beginning of a raw_data_block() */
FDKcrcReset(&hTp->parser.adts.crcInfo);
hTp->globalFramePos = FDKgetValidBits(hBs);
}
if (err == TRANSPORTDEC_OK) {
hTp->numberOfRawDataBlocks--;
rawDataBlockLength = adtsRead_GetRawDataBlockLength(&hTp->parser.adts, (hTp->parser.adts.bs.num_raw_blocks-hTp->numberOfRawDataBlocks));
syncLayerFrameBits = (hTp->parser.adts.bs.frame_length<<3) - (startPos - FDKgetValidBits(hBs)) - syncLength;
if (syncLayerFrameBits <= 0) {
err = TRANSPORTDEC_SYNC_ERROR;
}
} else {
hTp->numberOfRawDataBlocks = 0;
}
break;
case TT_MP4_LOAS:
if (hTp->numberOfRawDataBlocks <= 0)
{
syncLayerFrameBits = FDKreadBits(hBs, 13);
hTp->parser.latm.m_audioMuxLengthBytes = syncLayerFrameBits;
syncLayerFrameBits <<= 3;
}
case TT_MP4_LATM_MCP1:
case TT_MP4_LATM_MCP0:
if (hTp->numberOfRawDataBlocks <= 0)
{
hTp->globalFramePos = FDKgetValidBits(hBs);
err = CLatmDemux_Read(
hBs,
&hTp->parser.latm,
hTp->transportFmt,
&hTp->callbacks,
hTp->asc,
ignoreBufferFullness);
if (err != TRANSPORTDEC_OK) {
if (err != TRANSPORTDEC_NOT_ENOUGH_BITS) {
err = TRANSPORTDEC_SYNC_ERROR;
}
} else {
hTp->numberOfRawDataBlocks = CLatmDemux_GetNrOfSubFrames(&hTp->parser.latm);
syncLayerFrameBits -= startPos - FDKgetValidBits(hBs) - (13);
}
} else {
err = CLatmDemux_ReadPayloadLengthInfo(hBs, &hTp->parser.latm);
if (err != TRANSPORTDEC_OK) {
err = TRANSPORTDEC_SYNC_ERROR;
}
}
if (err == TRANSPORTDEC_OK) {
rawDataBlockLength = CLatmDemux_GetFrameLengthInBits(&hTp->parser.latm);
hTp->numberOfRawDataBlocks--;
} else {
hTp->numberOfRawDataBlocks = 0;
}
break;
default:
{
syncLayerFrameBits = 0;
}
break;
}
}
headerBits += startPos - (INT)FDKgetValidBits(hBs);
bitsAvail -= headerBits;
checkLengthBits = syncLayerFrameBits;
/* Check if the whole frame would fit the bitstream buffer */
if (err == TRANSPORTDEC_OK) {
if ( (checkLengthBits+headerBits) > ((TRANSPORTDEC_INBUF_SIZE<<3)-7) ) {
/* We assume that the size of the transport bit buffer has been
chosen to meet all system requirements, thus this condition
is considered a synchronisation error. */
err = TRANSPORTDEC_SYNC_ERROR;
} else {
if ( bitsAvail < checkLengthBits ) {
err = TRANSPORTDEC_NOT_ENOUGH_BITS;
}
}
}
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
break;
}
if (err == TRANSPORTDEC_SYNC_ERROR) {
int bits;
/* Enforce re-sync of transport headers. */
hTp->numberOfRawDataBlocks = 0;
/* Ensure that the bit amount lands and a multiple of TPDEC_SYNCSKIP */
bits = (bitsAvail + headerBits) % TPDEC_SYNCSKIP;
/* Rewind - TPDEC_SYNCSKIP, in order to look for a synch one bit ahead next time. */
FDKpushBiDirectional(hBs, -(headerBits - TPDEC_SYNCSKIP) + bits);
bitsAvail += headerBits - TPDEC_SYNCSKIP - bits;
headerBits = 0;
}
/* Frame traversal */
if ( fTraverseMoreFrames )
{
/* Save parser context for early config discovery "rewind all frames" */
if ( (hTp->flags & TPDEC_EARLY_CONFIG) && !(hTp->flags & TPDEC_MINIMIZE_DELAY))
{
/* ignore buffer fullness if just traversing additional frames for ECD */
ignoreBufferFullness = 1;
/* Save context in order to return later */
if ( err == TRANSPORTDEC_OK && startPosFirstFrame == -1 ) {
startPosFirstFrame = FDKgetValidBits(hBs);
numRawDataBlocksFirstFrame = hTp->numberOfRawDataBlocks;
globalFramePosFirstFrame = hTp->globalFramePos;
rawDataBlockLengthFirstFrame = rawDataBlockLength;
headerBitsFirstFrame = headerBits;
errFirstFrame = err;
FDKmemcpy(contextFirstFrame, &hTp->parser, sizeof(transportdec_parser_t));
}
/* Break when config was found or it is not possible anymore to find a config */
if (startPosFirstFrame != -1 && (fConfigFound || err != TRANSPORTDEC_OK)) {
break;
}
}
if (err == TRANSPORTDEC_OK) {
FDKpushFor(hBs, rawDataBlockLength);
bitsAvail -= rawDataBlockLength;
numFramesTraversed++;
/* Ignore error here itentionally. */
transportDec_AdjustEndOfAccessUnit(hTp);
}
}
} while ( fTraverseMoreFrames || (err == TRANSPORTDEC_SYNC_ERROR && !(hTp->flags & TPDEC_SYNCOK)));
/* Restore context in case of ECD frame traversal */
if ( startPosFirstFrame != -1 && (fConfigFound || err != TRANSPORTDEC_OK) ) {
FDKpushBiDirectional(hBs, FDKgetValidBits(hBs) - startPosFirstFrame);
FDKmemcpy(&hTp->parser, contextFirstFrame, sizeof(transportdec_parser_t));
hTp->numberOfRawDataBlocks = numRawDataBlocksFirstFrame;
hTp->globalFramePos = globalFramePosFirstFrame;
rawDataBlockLength = rawDataBlockLengthFirstFrame;
headerBits = headerBitsFirstFrame;
err = errFirstFrame;
numFramesTraversed = 0;
}
/* Additional burst data mode buffer fullness check. */
if ( !(hTp->flags & (TPDEC_IGNORE_BUFFERFULLNESS|TPDEC_SYNCOK)) && err == TRANSPORTDEC_OK) {
err = additionalHoldOffNeeded(hTp, transportDec_GetBufferFullness(hTp), FDKgetValidBits(hBs) - syncLayerFrameBits);
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
hTp->holdOffFrames++;
}
}
/* Rewind for retry because of not enough bits */
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
FDKpushBack(hBs, headerBits);
headerBits = 0;
}
else {
/* reset hold off frame counter */
hTp->holdOffFrames = 0;
}
/* Return to last good frame in case of frame traversal but not ECD. */
if (numFramesTraversed > 0) {
FDKpushBack(hBs, rawDataBlockLengthPrevious);
if (err != TRANSPORTDEC_OK) {
hTp->numberOfRawDataBlocks = numRawDataBlocksPrevious;
headerBits = headerBitsPrevious;
}
err = TRANSPORTDEC_OK;
}
bail:
hTp->auLength[0] = rawDataBlockLength;
if (err == TRANSPORTDEC_OK) {
hTp->flags |= TPDEC_SYNCOK;
}
if (pHeaderBits != NULL) {
*pHeaderBits = headerBits;
}
if (err == TRANSPORTDEC_SYNC_ERROR) {
hTp->flags &= ~TPDEC_SYNCOK;
}
C_ALLOC_SCRATCH_END(contextFirstFrame, transportdec_parser_t, 1);
return err;
}
static
TRANSPORTDEC_ERROR synchronization(
HANDLE_TRANSPORTDEC hTp,
INT *pHeaderBits
)
{
TRANSPORTDEC_ERROR err = TRANSPORTDEC_OK, errFirstFrame = TRANSPORTDEC_OK;
HANDLE_FDK_BITSTREAM hBs = &hTp->bitStream[0];
INT syncLayerFrameBits = 0; /* Length of sync layer frame (i.e. LOAS) */
INT rawDataBlockLength = 0, rawDataBlockLengthPrevious;
INT totalBits;
INT headerBits = 0, headerBitsFirstFrame = 0, headerBitsPrevious;
INT numFramesTraversed = 0, fTraverseMoreFrames, fConfigFound = (hTp->flags & TPDEC_CONFIG_FOUND), startPosFirstFrame = -1;
INT numRawDataBlocksFirstFrame = 0, numRawDataBlocksPrevious, globalFramePosFirstFrame = 0, rawDataBlockLengthFirstFrame = 0;
INT ignoreBufferFullness = hTp->flags & (TPDEC_LOST_FRAMES_PENDING|TPDEC_IGNORE_BUFFERFULLNESS|TPDEC_SYNCOK);
/* Synch parameters */
INT syncLength; /* Length of sync word in bits */
UINT syncWord; /* Sync word to be found */
UINT syncMask; /* Mask for sync word (for adding one bit, so comprising one bit less) */
C_ALLOC_SCRATCH_START(contextFirstFrame, transportdec_parser_t, 1);
totalBits = (INT)FDKgetValidBits(hBs);
if (totalBits <= 0) {
err = TRANSPORTDEC_NOT_ENOUGH_BITS;
goto bail;
}
fTraverseMoreFrames = (hTp->flags & (TPDEC_MINIMIZE_DELAY|TPDEC_EARLY_CONFIG)) && ! (hTp->flags & TPDEC_SYNCOK);
/* Set transport specific sync parameters */
switch (hTp->transportFmt) {
case TT_MP4_ADTS:
syncWord = ADTS_SYNCWORD;
syncLength = ADTS_SYNCLENGTH;
break;
case TT_MP4_LOAS:
syncWord = 0x2B7;
syncLength = 11;
break;
default:
syncWord = 0;
syncLength = 0;
break;
}
syncMask = (1<<syncLength)-1;
do {
INT bitsAvail = 0; /* Bits available in bitstream buffer */
INT checkLengthBits; /* Helper to check remaining bits and buffer boundaries */
UINT synch; /* Current sync word read from bitstream */
headerBitsPrevious = headerBits;
bitsAvail = (INT)FDKgetValidBits(hBs);
if (hTp->numberOfRawDataBlocks == 0) {
/* search synchword */
FDK_ASSERT( (bitsAvail % TPDEC_SYNCSKIP) == 0);
if ((bitsAvail-syncLength) < TPDEC_SYNCSKIP) {
err = TRANSPORTDEC_NOT_ENOUGH_BITS;
headerBits = 0;
} else {
synch = FDKreadBits(hBs, syncLength);
if ( !(hTp->flags & TPDEC_SYNCOK) ) {
for (; (bitsAvail-syncLength) >= TPDEC_SYNCSKIP; bitsAvail-=TPDEC_SYNCSKIP) {
if (synch == syncWord) {
break;
}
synch = ((synch << TPDEC_SYNCSKIP) & syncMask) | FDKreadBits(hBs, TPDEC_SYNCSKIP);
}
}
if (synch != syncWord) {
/* No correct syncword found. */
err = TRANSPORTDEC_SYNC_ERROR;
} else {
err = TRANSPORTDEC_OK;
}
headerBits = syncLength;
}
} else {
headerBits = 0;
}
/* Save previous raw data block data */
rawDataBlockLengthPrevious = rawDataBlockLength;
numRawDataBlocksPrevious = hTp->numberOfRawDataBlocks;
/* Parse transport header (raw data block granularity) */
if (err == TRANSPORTDEC_OK )
{
err = transportDec_readHeader(
hTp,
hBs,
syncLength,
ignoreBufferFullness,
&rawDataBlockLength,
&fTraverseMoreFrames,
&syncLayerFrameBits,
&fConfigFound,
&headerBits
);
}
bitsAvail -= headerBits;
checkLengthBits = syncLayerFrameBits;
/* Check if the whole frame would fit the bitstream buffer */
if (err == TRANSPORTDEC_OK) {
if ( (checkLengthBits+headerBits) > ((TRANSPORTDEC_INBUF_SIZE<<3)-7) ) {
/* We assume that the size of the transport bit buffer has been
chosen to meet all system requirements, thus this condition
is considered a synchronisation error. */
err = TRANSPORTDEC_SYNC_ERROR;
} else {
if ( bitsAvail < checkLengthBits ) {
err = TRANSPORTDEC_NOT_ENOUGH_BITS;
}
}
}
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
break;
}
if (err == TRANSPORTDEC_SYNC_ERROR) {
int bits;
/* Enforce re-sync of transport headers. */
hTp->numberOfRawDataBlocks = 0;
/* Ensure that the bit amount lands at a multiple of TPDEC_SYNCSKIP */
bits = (bitsAvail + headerBits) % TPDEC_SYNCSKIP;
/* Rewind - TPDEC_SYNCSKIP, in order to look for a synch one bit ahead next time. */
FDKpushBiDirectional(hBs, -(headerBits - TPDEC_SYNCSKIP) + bits);
bitsAvail += headerBits - TPDEC_SYNCSKIP - bits;
headerBits = 0;
}
/* Frame traversal */
if ( fTraverseMoreFrames )
{
/* Save parser context for early config discovery "rewind all frames" */
if ( (hTp->flags & TPDEC_EARLY_CONFIG) && !(hTp->flags & TPDEC_MINIMIZE_DELAY))
{
/* ignore buffer fullness if just traversing additional frames for ECD */
ignoreBufferFullness = 1;
/* Save context in order to return later */
if ( err == TRANSPORTDEC_OK && startPosFirstFrame == -1 ) {
startPosFirstFrame = FDKgetValidBits(hBs);
numRawDataBlocksFirstFrame = hTp->numberOfRawDataBlocks;
globalFramePosFirstFrame = hTp->globalFramePos;
rawDataBlockLengthFirstFrame = rawDataBlockLength;
headerBitsFirstFrame = headerBits;
errFirstFrame = err;
FDKmemcpy(contextFirstFrame, &hTp->parser, sizeof(transportdec_parser_t));
}
/* Break when config was found or it is not possible anymore to find a config */
if (startPosFirstFrame != -1 && (fConfigFound || err != TRANSPORTDEC_OK))
{
/* In case of ECD and sync error, do not rewind anywhere. */
if (err == TRANSPORTDEC_SYNC_ERROR)
{
startPosFirstFrame = -1;
fConfigFound = 0;
numFramesTraversed = 0;
}
break;
}
}
if (err == TRANSPORTDEC_OK) {
FDKpushFor(hBs, rawDataBlockLength);
bitsAvail -= rawDataBlockLength;
numFramesTraversed++;
/* Ignore error here itentionally. */
transportDec_AdjustEndOfAccessUnit(hTp);
}
}
} while ( fTraverseMoreFrames || (err == TRANSPORTDEC_SYNC_ERROR && !(hTp->flags & TPDEC_SYNCOK)));
/* Restore context in case of ECD frame traversal */
if ( startPosFirstFrame != -1 && (fConfigFound || err != TRANSPORTDEC_OK) ) {
FDKpushBiDirectional(hBs, FDKgetValidBits(hBs) - startPosFirstFrame);
FDKmemcpy(&hTp->parser, contextFirstFrame, sizeof(transportdec_parser_t));
hTp->numberOfRawDataBlocks = numRawDataBlocksFirstFrame;
hTp->globalFramePos = globalFramePosFirstFrame;
rawDataBlockLength = rawDataBlockLengthFirstFrame;
headerBits = headerBitsFirstFrame;
err = errFirstFrame;
numFramesTraversed = 0;
}
/* Additional burst data mode buffer fullness check. */
if ( !(hTp->flags & (TPDEC_LOST_FRAMES_PENDING|TPDEC_IGNORE_BUFFERFULLNESS|TPDEC_SYNCOK)) && err == TRANSPORTDEC_OK) {
err = additionalHoldOffNeeded(hTp, transportDec_GetBufferFullness(hTp), FDKgetValidBits(hBs) - syncLayerFrameBits);
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
hTp->holdOffFrames++;
}
}
/* Rewind for retry because of not enough bits */
if (err == TRANSPORTDEC_NOT_ENOUGH_BITS) {
FDKpushBack(hBs, headerBits);
headerBits = 0;
}
else {
/* reset hold off frame counter */
hTp->holdOffFrames = 0;
}
/* Return to last good frame in case of frame traversal but not ECD. */
if (numFramesTraversed > 0) {
FDKpushBack(hBs, rawDataBlockLengthPrevious);
if (err != TRANSPORTDEC_OK) {
hTp->numberOfRawDataBlocks = numRawDataBlocksPrevious;
headerBits = headerBitsPrevious;
}
err = TRANSPORTDEC_OK;
}
bail:
hTp->auLength[0] = rawDataBlockLength;
/* Detect pointless TRANSPORTDEC_NOT_ENOUGH_BITS error case, were the bit buffer is already full,
or no new burst packet fits. Recover by advancing the bit buffer. */
if ( (TRANSPORTDEC_NOT_ENOUGH_BITS == err) && (FDKgetValidBits(hBs) >= ((TRANSPORTDEC_INBUF_SIZE*8 - ((hTp->avgBitRate*hTp->burstPeriod)/1000)) - 7)) )
{
FDKpushFor(hBs, TPDEC_SYNCSKIP);
err = TRANSPORTDEC_SYNC_ERROR;
}
if (err == TRANSPORTDEC_OK) {
hTp->flags |= TPDEC_SYNCOK;
}
if (fConfigFound) {
hTp->flags |= TPDEC_CONFIG_FOUND;
}
if (pHeaderBits != NULL) {
*pHeaderBits = headerBits;
}
if (err == TRANSPORTDEC_SYNC_ERROR) {
hTp->flags &= ~TPDEC_SYNCOK;
}
C_ALLOC_SCRATCH_END(contextFirstFrame, transportdec_parser_t, 1);
return err;
}
/**
* \brief adjust bit stream position and the end of an access unit.
* \param hTp transport decoder handle.
* \return error code.
*/
static
TRANSPORTDEC_ERROR transportDec_AdjustEndOfAccessUnit(HANDLE_TRANSPORTDEC hTp)
{
HANDLE_FDK_BITSTREAM hBs = &hTp->bitStream[0];
TRANSPORTDEC_ERROR err = TRANSPORTDEC_OK;
switch (hTp->transportFmt) {
case TT_MP4_LOAS:
case TT_MP4_LATM_MCP0:
case TT_MP4_LATM_MCP1:
if ( hTp->numberOfRawDataBlocks == 0 )
{
/* Do byte align at the end of AudioMuxElement. */
FDKbyteAlign(hBs, hTp->globalFramePos);
/* Check global frame length */
if (hTp->transportFmt == TT_MP4_LOAS && hTp->parser.latm.m_audioMuxLengthBytes > 0)
{
int loasOffset;
loasOffset = (hTp->parser.latm.m_audioMuxLengthBytes*8 + FDKgetValidBits(hBs)) - hTp->globalFramePos;
if (loasOffset != 0) {
FDKpushBiDirectional(hBs, loasOffset);
/* For ELD and other payloads there is an unknown amount of padding, so ignore unread bits, but
throw an error only if too many bits where read. */
if (loasOffset < 0) {
err = TRANSPORTDEC_PARSE_ERROR;
}
}
}
}
break;
case TT_MP4_ADTS:
if (hTp->parser.adts.bs.protection_absent == 0)
{
int offset;
/* Calculate offset to end of AU */
offset = hTp->parser.adts.rawDataBlockDist[hTp->parser.adts.bs.num_raw_blocks-hTp->numberOfRawDataBlocks]<<3;
/* CAUTION: The PCE (if available) is declared to be a part of the header! */
offset -= hTp->accessUnitAnchor[0] - FDKgetValidBits(hBs) + 16 + hTp->parser.adts.bs.num_pce_bits;
FDKpushBiDirectional(hBs, offset);
}
if (hTp->parser.adts.bs.num_raw_blocks > 0 && hTp->parser.adts.bs.protection_absent == 0) {
/* Note this CRC read currently happens twice because of transportDec_CrcCheck() */
hTp->parser.adts.crcReadValue = FDKreadBits(hBs, 16);
}
if ( hTp->numberOfRawDataBlocks == 0 )
{
/* Check global frame length */
if (hTp->parser.adts.bs.protection_absent == 0)
{
int offset;
offset = (hTp->parser.adts.bs.frame_length*8 - ADTS_SYNCLENGTH + FDKgetValidBits(hBs)) - hTp->globalFramePos;
if (offset != 0) {
FDKpushBiDirectional(hBs, offset);
}
}
}
break;
default:
break;
}
return err;
}