[FFmpeg-devel] DVD subtitles hacking

[Matt Zagrabelny]

[Please Cc me, I am not subscribed to -devel.]

Hello!

I've tried a variety of convoluted processes to convert DVD subtitles to
SRT or WebVTT subtitle files with varying levels of success. The process
has always been painful and convoluted.

I have seen chatter about the following ticket:

https://trac.ffmpeg.org/ticket/2391

Tools like vobsub2srt need .idx and .sub files and usually a .ifo file, too.

However, it seems mplayer can easily display the subtitles of a VOB ripped
from a DVD without the IFO files. I believe that mplayer uses ffmpeg
libraries. Thus it would seem that ffmpeg could do the work of converting
the subtitle streams in a ripped DVD VOB to SRT or WebVTT (with an
appropriate OCR library, libtesseract perhaps.)

I have no experience hacking on ffmpeg, but this itch is rather bothersome.

Is anyone with ffmpeg hacking experience interested in this enhancement? We
could talk on or off list about working toward a solution.

If I were to contemplate undertaking this, I would need to:

- extract the subtitle image
- get the timestamps (image displayed, image no longer displayed)

Where would I look to get started on the above two tasks?

Thanks for any help, pointers, or feedback!

-m