Hello,
I have a strange problem and do not find a solution. I try to extract a serie
of Pictures in a MPEG2-Transport-Stream. The I-Frames are nice and ok, but
the other frames (P- and B-frames) are corrupted. My Code is the following:
int i = 0; // Pic Nr.
int frameFinished = 0;
do
{
if (packet.stream_index == mStreamID) // at this step I've
already read a
packet!
{
int bytesRemaining = packet.size;
int bytesDecoded = 0;
bytesDecoded = avcodec_decode_video(mPCodecCtx, frame, &frameFinished,
packet.data, packet.size);
if (frameFinished)
{
i++;
if (i == 12) // only 12 pictures for test
return;
cout << frame->pict_type << " dekodiert!" << endl;
int numBytes=avpicture_get_size(PIX_FMT_RGB24, mPCodecCtx->width,
mPCodecCtx->height);
uint8_t* imgbuf = (uint8_t*) av_malloc(numBytes*sizeof(uint8_t));
avpicture_fill((AVPicture *)pFrameRGB, imgbuf, PIX_FMT_RGB24,
mPCodecCtx->width, mPCodecCtx->height);
img_convert_ctx = sws_getContext(mPCodecCtx->width,
mPCodecCtx->height,
mPCodecCtx->pix_fmt,
mPCodecCtx->width,
mPCodecCtx->height,
PIX_FMT_RGB24,
SWS_BICUBIC, NULL, NULL, NULL);
sws_scale(img_convert_ctx, frame->data, frame->linesize,
0, mPCodecCtx->height, pFrameRGB->data,
pFrameRGB->linesize);
// Bild als PPM speichern
int flength = (mPCodecCtx->width * mPCodecCtx-> height * 3) + 15;
rawframe = new uint8_t[flength+1];
sprintf((char*)rawframe,"P6\n%d %d\n255\n", mPCodecCtx->width,
mPCodecCtx->height);
// dekodierten Bildinhalt kopieren
int buf_stelle = 15; // Nach dem PPM-Bild-Header
for(int y=0; y<mPCodecCtx->height; y++)
{
memcpy(&rawframe[buf_stelle],
pFrameRGB->data[0]+y*pFrameRGB->linesize[0], mPCodecCtx->width*3);
buf_stelle += mPCodecCtx->width*3;
}
flength = buf_stelle;
ostringstream Str;
Str << i;
string filename = "pic" + Str.str() + ".ppm";
FILE* fp = fopen(filename.c_str(),"wb");
fwrite(rawframe, flength, 1, fp);
fclose(fp);
}
}
av_free_packet(&packet);
} while (av_read_frame(mPAVFile->_formatContext(), &packet) >= 0);
After the extraction I get only nice I-Frames. The rest of the pictures are
corrupted. May anyone help me?
regards,
Sven
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