libavcodec video decoding not working

Question

I am trying to decode video encoded with H264. I am sending AVPacket's data and its size to decoder code. there I am trying to decode the frame and display it on a GUI. problem is when I am decoding the frame it is returning same number of frame byte as the size of packet means it is not decompressing the data. Can any one tell what will be the problem. My encoding program is working fine.

here is code for encoding

  static struct SwsContext *img_convert_ctx;
  pkt.data = NULL;   
  pkt.size = 0; 


  avpicture_fill((AVPicture *)srcFrame, frame,AV_PIX_FMT_BGR24, 640, 480);
 if(img_convert_ctx == NULL) {
  int w = 640;
  int h = 480;
  img_convert_ctx = sws_getContext(w, h, 
      AV_PIX_FMT_BGR24, c->width, c->height, PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
   if(img_convert_ctx == NULL) {
    fprintf(stderr, "Cannot initialize the conversion context!\n");
  }
}
  sws_scale(img_convert_ctx, srcFrame->data, srcFrame->linesize, 0,480,picture->data, picture->linesize);


  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) {

        vdec.decode_frame(pkt.data ,pkt.size);

        av_free_packet(&pkt);
    }

decoder code...

    int len ,got_frame;

avpkt.size = data_length;

avpkt.data = frame_buffer;

if(!frame_buffer){

return "frame buffer empty\n";

}

len = avcodec_decode_video2(avctx ,frame ,&got_frame ,&avpkt);

if( len < 0){

    return "error while decoding\n";

}

if( got_frame ){

static struct SwsContext *img_convert_ctx;  

 if(img_convert_ctx == NULL) {

  img_convert_ctx = sws_getContext(w, h, 
      PIX_FMT_YUV420P, avctx->width,
      avctx->height, PIX_FMT_BGR24, 
      SWS_BICUBIC, NULL, NULL, NULL);

   if(img_convert_ctx == NULL) {

    return  "Cannot initialize the conversion context!\n";

  }

}

j=sws_scale(img_convert_ctx, 
    frame->data , frame->linesize ,
    0, h ,picture->data,
    picture->linesize );

if(j==0){

exit(1);

}

I am initializing all other code like AVCodecContext and Codec into other method.

Please help me to find the solution.

pogorskiy pogorskiy · Accepted Answer · 2013-02-05T11:45:39

The avcodec_decode_video2 function should return the number of bytes processed, not the number of bytes of result picture. You just have to check the value of got_frame to find out when decoded a complete frame.

libavcodec video decoding not working

1 Answers