/* get information on the input stream (e.g. format, bitrate, framerate) */
ret = avformat_find_stream_info(input_format_ctx, NULL);
if (ret < 0) {
/* get information on the input stream (e.g. format, bitrate, framerate) */
ret = avformat_find_stream_info(input_format_ctx, NULL);
if (ret < 0) {