[FFmpeg-devel] [PATCH] lavc: Replace 181 magic number with ITU_T_T35_COUNTRY_CODE_US

Devin Heitmueller devin.heitmueller at ltnglobal.com
Mon Mar 31 18:55:19 EEST 2025


Hello Tomas,

On Mon, Mar 31, 2025 at 11:24 AM Tomas Härdin <git at haerdin.se> wrote:
> > Yeah, I didn't have a particularly positive experience with
> > libcaption, despite the fact that I know it's what a number of
> > projects use (including OBS).  Everytime I look at that code I spot a
> > whole pile of things they are doing wrong.  Probably the most obvious
> > is that they don't properly do rate control for the 608/708 tuples to
> > embed in the stream, so the resulting stream won't work properly with
> > many decoders/transcoders.  This was actually one reason I wrote the
> > vf_ccrepack filter in ffmpeg, to deal with cases where somebody used
> > libcaption to embed CC into a TS.  The ccrepack filter puts the
> > caption tuples into.a queue and then re-embeds them at the appropriate
> > rate given the target framerate.
>
> Did you report this to libcaption's devs?

Respectfully, libcaption is essentially a dead project.  The main repo
hasn't had a commit in seven years, there are numerous separate forks
with fixes/improvements.  The OBS project has its own repo with fixes
they've made, and they are well aware of the problem (in fact the
ticket includes some discussion I had with one of the developers).

https://github.com/obsproject/obs-studio/issues/4006

Devin

-- 
Devin Heitmueller,
LTN Global Communications
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w: https://ltnglobal.com  e: devin.heitmueller at ltnglobal.com


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