encoding direcshow frame buffers by using libavcodec - visual-c++

Question

I am trying to encode a stream buffer of frames grabbed by ISampleGrabber(directshow) by using libavcodec. After encoding those frame I am writing it into a file. But after completion file contains only green frames.
hers is code for grabbing frames and encoding it...
void DSGrabberCallback::initFFMpeg(){
const char* filename="G:/test1.mpg";
avcodec_register_all();
printf("Encode video file %s\n", filename);
AVCodecID codec_id=AV_CODEC_ID_MPEG2VIDEO;
codec = avcodec_find_encoder(codec_id);
c = avcodec_alloc_context3(codec);
if (!c) {
fprintf(stderr, "Could not allocate video codec context\n");
}
c->bit_rate = 4000000;
c->width = 320;
c->height = 240;
AVRational test;
test.den=25;
test.num=1;
c->time_base= test;
c->gop_size = 10;
//c->max_b_frames=1;
c->pix_fmt = AV_PIX_FMT_YUV420P;
if(codec_id == AV_CODEC_ID_H264)
av_opt_set(c->priv_data, "preset", "slow", 0);
if (avcodec_open2(c, codec, NULL) < 0) {
fprintf(stderr, "Could not open codec\n");
}
f = fopen(filename, "wb");
if (!f) {
fprintf(stderr, "Could not open %s\n", filename);
}
picture = alloc_picture(c->pix_fmt, c->width, c->height);
/*picture->format = c->pix_fmt;
picture->width = c->width;
picture->height = c->height;*/
av_init_packet(&pkt);
}
void DSGrabberCallback::encodeFrame(unsigned char *frame,ULONG size){
std::cout<<"called.....";
pkt.data = NULL;
pkt.size = 0;
picture->data[0]=frame;
fflush(stdout);
picture->pts=counter;
ret = avcodec_encode_video2(c, &pkt, picture, &got_output);
if (ret < 0) {
fprintf(stderr, "Error encoding frame\n");
}
if (got_output) {
printf("Write frame %3d (size=%5d)\n", counter, pkt.size);
fwrite(pkt.data, 1, pkt.size, f);
av_free_packet(&pkt);
}
}
STDMETHODIMP DSGrabberCallback::SampleCB(double time, IMediaSample* sample)
{
BYTE* data = NULL;
ULONG length = 0;
m_bytes=NULL;
counter=counter+1;
if(FAILED(sample->GetPointer(&data)))
{
return E_FAIL;
}
length = sample->GetActualDataLength();
if(length == 0)
{
return S_OK;
}
if(!m_bytes || m_bytesLength < length)
{
if(m_bytes)
{
delete[] m_bytes;
}
m_bytes = new unsigned char[length];
m_bytesLength = length;
}
if(true)
{
for(size_t row = 0 ; row < 480 ; row++)
{
memcpy((m_bytes + row * 640 * 2), data + (480 - 1 - row) * 640 * 2,
640 * 2);
}
}
std::cout<<"hiiiiiiiiiiiiiiiiiiiiiiii";
// memcpy(m_bytes, data, length);
// std::cout<<"called............... "<<m_bytes<<"\n";
if(counter<500){
encodeFrame(m_bytes,length);
}else{
fwrite(endcode, 1, sizeof(endcode), f);
fclose(f);
avcodec_close(c);
av_free(c);
av_freep(&picture->data[0]);
avcodec_free_frame(&picture);
printf("\n");
exit(1);
}
//rtp.sendRTP(data,length);
//sample->Release();
//printf("Sample received: %p %u\n", data, length);
return S_OK;
}
can anyone tell me where is the problem.

Answer 1

Now working fine. Actually I forgot to convert the image buffer into YUV420P format. I have added some code for scaling the buffer into YUV format and everything is fine now. Thank you Wimmel and Roman R.