MediaTime M2VParser::CountBFrames(){
//We count after the first chunk.
MediaTime count = 0;
if(m_eos) return 0;
if(notReachedFirstGOP) return 0;
for(size_t i = 1; i < chunks.size(); i++){
MPEGChunk* c = chunks[i];
if(c->GetType() == MPEG_VIDEO_PICTURE_START_CODE){
MPEG2PictureHeader h;
ParsePictureHeader(c, h);
if(h.frameType == MPEG2_B_FRAME){
count += GetFrameDuration(h);
}else{
return count;
}
}
}
return -1;
}
//Reads frames until it can timestamp them, usually reads until it has
//an I, P, B+, P...this way it can stamp them all and set references.
//NOTE: references aren't yet used by our system but they are kept up
//with in this plugin.
int32_t M2VParser::FillQueues(){
if(chunks.empty()){
return -1;
}
bool done = false;
while(!done){
MediaTime myTime = currentStampingTime;
MPEGChunk* chunk = chunks.front();
while (chunk->GetType() != MPEG_VIDEO_PICTURE_START_CODE) {
if (chunk->GetType() == MPEG_VIDEO_GOP_START_CODE) {
if (gopChunk)
delete gopChunk;
gopChunk = chunk;
} else if (chunk->GetType() == MPEG_VIDEO_SEQUENCE_START_CODE) {
if (seqHdrChunk)
delete seqHdrChunk;
ParseSequenceHeader(chunk, m_seqHdr);
seqHdrChunk = chunk;
}
chunks.erase(chunks.begin());
if (chunks.empty())
return -1;
chunk = chunks.front();
}
MPEG2PictureHeader picHdr;
ParsePictureHeader(chunk, picHdr);
MediaTime bcount;
if(myTime == nextSkip){
myTime+=nextSkipDuration;
currentStampingTime=myTime;
}
switch(picHdr.frameType){
case MPEG2_I_FRAME:
bcount = CountBFrames();
if(bcount > 0){ //..BBIBB..
myTime += bcount;
nextSkip = myTime;
nextSkipDuration = GetFrameDuration(picHdr);
}else{ //IPBB..
if(bcount == -1 && !m_eos)
return -1;
currentStampingTime += GetFrameDuration(picHdr);;
}
ShoveRef(myTime);
QueueFrame(chunk, myTime, picHdr);
notReachedFirstGOP = false;
break;
case MPEG2_P_FRAME:
bcount = CountBFrames();
if(firstRef == -1) break;
if(bcount > 0){ //..PBB..
myTime += bcount;
nextSkip = myTime;
nextSkipDuration = GetFrameDuration(picHdr);
}else{ //..PPBB..
if(bcount == -1 && !m_eos) return -1;
currentStampingTime+=GetFrameDuration(picHdr);
}
ShoveRef(myTime);
QueueFrame(chunk, myTime, picHdr);
break;
default: //B-frames
if(firstRef == -1 || secondRef == -1) break;
QueueFrame(chunk, myTime, picHdr);
currentStampingTime+=GetFrameDuration(picHdr);
}
chunks.erase(chunks.begin());
delete chunk;
if (chunks.empty())
return -1;
}
return 0;
}
//Maintains the time of the last start of GOP and uses the temporal_reference
//field as an offset.
int32_t M2VParser::FillQueues(){
if(chunks.empty()){
return -1;
}
bool done = false;
while(!done){
MediaTime myTime;
MPEGChunk* chunk = chunks.front();
while (chunk->GetType() != MPEG_VIDEO_PICTURE_START_CODE) {
if (chunk->GetType() == MPEG_VIDEO_GOP_START_CODE) {
ParseGOPHeader(chunk, m_gopHdr);
if (frameNum != 0) {
gopPts = highestPts + 1;
}
if (gopChunk)
delete gopChunk;
gopChunk = chunk;
gopNum++;
/* Perform some sanity checks */
if(waitSecondField){
mxerror(Y("Single field frame before GOP header detected. Fix the MPEG2 video stream before attempting to multiplex it.\n"));
}
if(!waitQueue.empty()){
mxwarn(Y("Shortened GOP detected. Some frames have been dropped. You may want to fix the MPEG2 video stream before attempting to multiplex it.\n"));
FlushWaitQueue();
}
if(m_gopHdr.brokenLink){
mxinfo(Y("Found group of picture with broken link. You may want use smart reencode before attempting to multiplex it.\n"));
}
// There are too many broken videos to do the following so ReferenceBlock will be wrong for broken videos.
/*
if(m_gopHdr.closedGOP){
ClearRef();
}
*/
} else if (chunk->GetType() == MPEG_VIDEO_SEQUENCE_START_CODE) {
if (seqHdrChunk)
delete seqHdrChunk;
ParseSequenceHeader(chunk, m_seqHdr);
seqHdrChunk = chunk;
}
chunks.erase(chunks.begin());
if (chunks.empty())
return -1;
chunk = chunks.front();
}
MPEG2PictureHeader picHdr;
ParsePictureHeader(chunk, picHdr);
if (picHdr.pictureStructure == 0x03) {
usePictureFrames = true;
}
myTime = gopPts + picHdr.temporalReference;
invisible = false;
if (myTime > highestPts)
highestPts = myTime;
switch(picHdr.frameType){
case MPEG2_I_FRAME:
PrepareFrame(chunk, myTime, picHdr);
notReachedFirstGOP = false;
break;
case MPEG2_P_FRAME:
if(firstRef == -1) break;
PrepareFrame(chunk, myTime, picHdr);
break;
default: //B-frames
if(firstRef == -1 || secondRef == -1){
if(!m_gopHdr.closedGOP && !m_gopHdr.brokenLink){
if(gopNum > 0){
mxerror(Y("Found B frame without second reference in a non closed GOP. Fix the MPEG2 video stream before attempting to multiplex it.\n"));
} else if (!probing && !bFrameMissingReferenceWarning){
mxwarn(Y("Found one or more B frames without second reference in the first GOP. You may want to fix the MPEG2 video stream or use smart reencode before attempting to multiplex it.\n"));
bFrameMissingReferenceWarning = true;
}
}
invisible = true;
}
PrepareFrame(chunk, myTime, picHdr);
}
frameNum++;
chunks.erase(chunks.begin());
delete chunk;
if (chunks.empty())
return -1;
}
return 0;
}