void parsePkt(AVPacket* pkt, std::vector<unsigned long>& result){
unsigned long keyIndex = 4;
unsigned long currentSegmentLength = 0;
unsigned long size = pkt->size;
uint8_t* data = pkt->data;
if (getNalSize(data, keyIndex) + 4 == size){
NalType type = getNalType(data, keyIndex);
if (type == H264Analyst::NalType::NAL_IDR_Slice || type == H264Analyst::NalType::NAL_Slice){
result.push_back(keyIndex);
}
return;
}
while (keyIndex < size){
auto type = getNalType(data, keyIndex);
if (NalType::NAL_IDR_Slice == type || NalType::NAL_Slice == type){
result.push_back(keyIndex);
}
currentSegmentLength = getNalSize(data, keyIndex);
keyIndex += currentSegmentLength + 4;
continue;
}
}
/**
Decodes the video stream until the first frame with number larger or equal than 'after' is found.
Returns:
- true if a frame is found, false otherwise.
- the image as a QImage if img is non-null
- time frame time, if frametime is non-null
- the frame number, if framenumber is non-null
All times are in milliseconds.
**/
bool QVideoDecoder::skipFrame()
{
if(!ok)
return false;
// Read a frame
if(av_read_frame(pFormatCtx, &packet) < 0)
return false; // Frame read failed (e.g. end of stream)
bool done = false;
if(0x67 != getNalType(packet.data, packet.size)) {
done = true;
avcodec_flush_buffers(pCodecCtx);
av_free_packet(&packet); // Free the packet that was allocated by av_read_frame
DesiredFrameNumber++;
} else {
while(!done)
{
// Read a frame
//int status = av_read_frame(pFormatCtx, &packet);
//if(status<0)
// return false; // Frame read failed (e.g. end of stream)
//printf("Packet of stream %d, size %d\n",packet.stream_index,packet.size);
if(packet.stream_index==videoStream)
{
// Is this a packet from the video stream -> decode video frame
ffmpeg::AVRational millisecondbase = {1, 1000};
int f = packet.dts;
int t = ffmpeg::av_rescale_q(packet.dts,pFormatCtx->streams[videoStream]->time_base,millisecondbase);
if(LastFrameOk==false)
{
LastFrameOk=true;
LastLastFrameTime=LastFrameTime=t;
LastLastFrameNumber=LastFrameNumber=f;
}
else
{
// If we decoded 2 frames in a row, the last times are okay
LastLastFrameTime = LastFrameTime;
LastLastFrameNumber = LastFrameNumber;
LastFrameTime=t;
LastFrameNumber=f;
}
int frameFinished;
avcodec_decode_video2(pCodecCtx,pFrame,&frameFinished,&packet);
// Did we get a video frame?
if(frameFinished)
{
// Convert the image format (init the context the first time)
int w = pCodecCtx->width;
int h = pCodecCtx->height;
img_convert_ctx = ffmpeg::sws_getCachedContext(img_convert_ctx,w, h, pCodecCtx->pix_fmt, w, h, ffmpeg::PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);
if(img_convert_ctx == NULL)
{
printf("Cannot initialize the conversion context!\n");
return false;
}
ffmpeg::sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);
// Convert the frame to QImage
LastFrame=QImage(w,h,QImage::Format_RGB888);
for(int y=0; y<h; y++)
memcpy(LastFrame.scanLine(y),pFrameRGB->data[0]+y*pFrameRGB->linesize[0],w*3);
// Set the time
DesiredFrameTime = ffmpeg::av_rescale_q(0,pFormatCtx->streams[videoStream]->time_base,millisecondbase);
LastFrameOk=true;
done = true;
DesiredFrameNumber++;
//} // frame of interest
} // frameFinished
} // stream_index==videoStream
av_free_packet(&packet); // Free the packet that was allocated by av_read_frame
}
}
//printf("Returning new frame %d @ %d. LastLastT: %d. LastLastF: %d. LastFrameOk: %d\n",LastFrameNumber,LastFrameTime,LastLastFrameTime,LastLastFrameNumber,(int)LastFrameOk);
//printf("\n");
return done; // done indicates whether or not we found a frame
}
