iformat = av_find_input_format("image2pipe");
if ((ret = avformat_open_input(&format_ctx, filename, iformat, NULL)) < 0) {
av_log(log_ctx, AV_LOG_ERROR,
iformat = av_find_input_format("image2pipe");
if ((ret = avformat_open_input(&format_ctx, filename, iformat, NULL)) < 0) {
av_log(log_ctx, AV_LOG_ERROR,