while GetNextFrame pFormatCtx pCodecCtx videoStream pFrame SwsContext

    while(GetNextFrame(pFormatCtx, pCodecCtx, videoStream, pFrame))
    {
        SwsContext *img_convert_ctx = sws_getContext(pCodecCtx->width,
                                                     pCodecCtx->height,
                                                     pCodecCtx->pix_fmt,
                                                     pCodecCtx->width,
                                                     pCodecCtx->height,
                                                     PIX_FMT_RGB24,
                                                     SWS_FAST_BILINEAR,
                                                     NULL, NULL, NULL);
        
        sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0,
                  pCodecCtx->height,
                  pFrameRGB->data, pFrameRGB->linesize);
        SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i);
        i++;
    }