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;
}
/**
* \brief Synchronize to stream and estimate the amount of missing access units due
* to a current synchronization error in case of constant average bit rate.
*/
static
TRANSPORTDEC_ERROR transportDec_readStream ( HANDLE_TRANSPORTDEC hTp, const UINT layer )
{
TRANSPORTDEC_ERROR error = TRANSPORTDEC_OK;
HANDLE_FDK_BITSTREAM hBs = &hTp->bitStream[layer];
INT nAU = -1;
INT headerBits;
INT bitDistance, bfDelta;
/* Obtain distance to next synch word */
bitDistance = FDKgetValidBits(hBs);
error = synchronization(hTp, &headerBits);
bitDistance -= FDKgetValidBits(hBs);
FDK_ASSERT(bitDistance >= 0);
if (error == TRANSPORTDEC_SYNC_ERROR || (hTp->flags & TPDEC_LOST_FRAMES_PENDING))
{
/* Check if estimating lost access units is feasible. */
if (hTp->avgBitRate > 0 && hTp->asc[0].m_samplesPerFrame > 0 && hTp->asc[0].m_samplingFrequency > 0)
{
if (error == TRANSPORTDEC_OK)
{
int aj;
aj = transportDec_GetBufferFullness(hTp);
if (aj > 0) {
bfDelta = aj;
} else {
bfDelta = 0;
}
/* sync was ok: last of a series of bad access units. */
hTp->flags &= ~TPDEC_LOST_FRAMES_PENDING;
/* Add up bitDistance until end of the current frame. Later we substract
this frame from the grand total, since this current successfully synchronized
frame should not be skipped of course; but it must be accounted into the
bufferfulness math. */
bitDistance += hTp->auLength[0];
} else {
if ( !(hTp->flags & TPDEC_LOST_FRAMES_PENDING) ) {
/* sync not ok: one of many bad access units. */
hTp->flags |= TPDEC_LOST_FRAMES_PENDING;
bfDelta = - (INT)hTp->lastValidBufferFullness;
} else {
bfDelta = 0;
}
}
{
int num, denom;
/* Obtain estimate of number of lost frames */
num = hTp->asc[0].m_samplingFrequency * (bfDelta + bitDistance) + hTp->remainder;
denom = hTp->avgBitRate * hTp->asc[0].m_samplesPerFrame;
if (num > 0) {
nAU = num / denom;
hTp->remainder = num % denom;
} else {
hTp->remainder = num;
}
if (error == TRANSPORTDEC_OK)
{
/* Final adjustment of remainder, taken -1 into account because current
frame should not be skipped, thus substract -1 or do nothing instead
of +1-1 accordingly. */
if ( (denom - hTp->remainder) >= hTp->remainder ) {
nAU--;
}
if (nAU < 0) {
/* There was one frame too much concealed, so unfortunately we will have to skip one good frame. */
transportDec_EndAccessUnit(hTp);
error = synchronization(hTp, &headerBits);
nAU = -1;
#ifdef DEBUG
FDKprintf("ERROR: Bufferfullness accounting failed. remainder=%d, nAU=%d\n", hTp->remainder, nAU);
#endif
}
hTp->remainder = 0;
/* Enforce last missed frames to be concealed. */
if (nAU > 0) {
FDKpushBack(hBs, headerBits);
}
}
}
}
}
/* Be sure that lost frames are handled correctly. This is necessary due to some
sync error sequences where later it turns out that there is not enough data, but
the bits upto the sync word are discarded, thus causing a value of nAU > 0 */
if (nAU > 0) {
error = TRANSPORTDEC_SYNC_ERROR;
}
hTp->missingAccessUnits = nAU;
return error;
}
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;
}
