[FFmpeg-user] MP4 with 9 subtitle streams

[Mark Filipak]

On Sat, Sep 23, 2023 at 12:21 PM Ferdi Scholten <ferdi at sttc-nlp.nl> wrote:
>
> >> Le sam. 23 sept. 2023 à 17:38, Mark Filipak
> >> <markfilipak.imdb at gmail.com>  a écrit :
> >>> On Sat, Sep 23, 2023 at 2:29 AM Paul B Mahol<onemda at gmail.com>  wrote:
> >>>> On 9/23/23, Mark Filipak<markfilipak.imdb at gmail.com>  wrote:
> >>>>> Why doesn't this work? I made an MP4 with 9 subtitle streams via
> >>>>> HandBrake. I think ffmpeg and HandBrake use the same libraries.
> > -snip-
> >>> "codec not currently supported in container [mp4]" is obviously not
> >>> true. I've proven that MP4 does support at least 9 SRT subtitles.
> >> I don't think it's the number of subs
> > I agree.
> >
> >> but rather the subrip format (aka. codec)
> > I don't agree. HandBrake has no problem with it. Whatever HandBrake
> > can do, ffmpeg can also do. The matter is How.
>
> srt subtitles are not officially supported by the mp4 specifications.

Do you know how I can get the MP4 specifications? And... what
percentage of the things being done are in specifications? 100%? 75%?
I find the MPEG specifications (ITU, actually) to be vague.

> They need to be converted to TTXT format,

What is TTXT format? Do you know how I can get specifications?

> Furthermore for ffmpeg to do
> that the encoding of the srt file needs to be UTF8, other formats are
> (supposedly) not supported. (default encoding for srt is Windows-1252)

Okay, fine. (I've never seen an SRT that wasn't UTF8.)