[FFmpeg-devel] [PATCH 1/3] ffmpeg: Don't print graphs if there are no graphs to print

[softworkz .]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Mark
> Thompson
> Sent: Samstag, 17. Mai 2025 13:14
> To: ffmpeg-devel at ffmpeg.org
> Subject: [FFmpeg-devel] [PATCH 1/3] ffmpeg: Don't print graphs if there are no
> graphs to print
> 
> Avoids writing an empty json blob in setup error cases.
> ---
>  fftools/ffmpeg.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 964770df23..ad28cff78d 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -309,7 +309,8 @@ const AVIOInterruptCB int_cb = { decode_interrupt_cb, NULL
> };
> 
>  static void ffmpeg_cleanup(int ret)
>  {
> -    if (print_graphs || print_graphs_file)
> +    if ((print_graphs || print_graphs_file) &&
> +        (nb_filtergraphs > 0 || nb_output_files > 0))
>          print_filtergraphs(filtergraphs, nb_filtergraphs, input_files,
> nb_input_files, output_files, nb_output_files);

The feature is not just about filter graphs, that's why it's been renamed
as "Execution Graph Printing". It also works when no filter graphs are
in play at all. 
Here's an example:

https://softworkz.github.io/ffmpeg_output_apis/1_nofilters_3_in_1_out.html


As for the nb_output_files check, I'm not sure - is it 0 or 1 in case of
-f null output?

Thanks
sw