会ffmpeg 的请进！该怎么解决

while(av_read_frame(pDlg->pFormatCtx, &pDlg->packet) >= 0) 
    {
        // Is this a packet from the video stream?
        if(pDlg->packet.stream_index == pDlg->videoStream) 
        {
            // Decode video frame
            avcodec_decode_video(pDlg->pCodecCtx, pDlg->pFrame, &pDlg->frameFinished,
                pDlg->packet.data, pDlg->packet.size);

            // Did we get a video frame?
            if(pDlg->frameFinished) 
            {
                AVPicture pict;

                // Convert the image from its native format to RGB

                struct SwsContext *img_convert_ctx;
                img_convert_ctx = sws_getContext(pDlg->pCodecCtx->width,pDlg->pCodecCtx->height, pDlg->pCodecCtx->pix_fmt,
                    pDlg->pCodecCtx->width,pDlg->pCodecCtx->height,PIX_FMT_YUVJ420P,SWS_BICUBIC, NULL,NULL,NULL);      
                if(img_convert_ctx == NULL)
                {
                    fprintf(stderr, "Cannot initialize the conversion context!\n");
                    getchar();
                }

                // 将图片转换为RGB格式
                sws_scale(img_convert_ctx,pDlg->pFrame->data,pDlg->pFrame->linesize,0,
                    pDlg->pCodecCtx->height,pict.data,pict.linesize);

                //pDlg->ShowVido(RGBbuf);
                
                Sleep(50);
            }
        }
        // Free the packet that was allocated by av_read_frame
        av_free_packet(&pDlg->packet);
    }