[FFmpeg-user] sntsc

[Mark Filipak]

On 1/8/24 01:46, Andrew Randrianasulu wrote:
> Well, here lies the problem for us!
> 
> Ffmpeg (command line utility) encodes those files straight away, so for
> example VLC displays them correctly. But our software (cinelerra-gg) so far
> was not setting st->sample_aspect_ratio so say webm encodes were by default
> with wrong Display aspect ratio in  both VLC and GNOME filemanager previews.

You can set DAR in ffmpeg to whatever you want.

> I hope now (after my patches under testing) we set  sample aspect ratio in
> both places (codecpar and st) so hopefully libav* based players will
> display them correctly out of the box.
Well, I don't know your tools, but MPEG-TSs actually has no SAR setting. It has no PAR setting, 
either, but you can set PAR by setting horizontal_size_value & vertical_size_value. I don't know how 
to set them without ffmpeg reacting by actually scaling the samples. That's not what you will want. 
You want to correct the aspect without scaling. I don't know how to do that.

Perhaps someone else can advise you. I'd sure like to know how to change MPEG tags.

-- Mark.