[FFmpeg-devel] [PATCH 1/2] avcodec/{ass, webvttdec}: fix handling of backslashes

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Fri Feb 4 03:30:37 EET 2022


Oneric:
> On Thu, Feb 03, 2022 at 20:51:16 +0000, Soft Works wrote:
>> I think when you inject that word-joiner as a workaround for ass
>> parsing, you'll also need to make sure that it gets removed
>> when encoding to other formats.
> 
> There's no way of knowing whether the word-joiner comes from
> a conversion performed by ffmpeg in the past or already existed
> in the original source.
> However, the wordjoiner does not alter the visually appearance and
> is unlikely to change line-breaking properties; that's why I chose
> a word-joiner. Therefore I don't think removing (only) the inserted
> word-joiners is possible, but also not necessary.
> 
> Also, was the wrong \\ recollapsed into a single \ somehwere? If yes,
> then this code can be dropped as well (but I don't know where it is).
> 
> My biggest concern with this is the unconditional assumption of UTF-8 in
> ff_ass_bprint_text_event? Is there a way to improve on this or does ffmpeg 
> convert all text to UTF-8 before it's passed to this function?

All text-based subtitles are supposed to be UTF-8 when they reach the
decoder; if it isn't, the user has to set the appropriate -sub_charenc
and -sub_charenc_mode.

- Andreas


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