[FFmpeg-devel] Subtitle filters in libavfilter

Stefano Sabatini stefasab at gmail.com
Wed Jan 30 20:15:55 CET 2013

On date Tuesday 2013-01-29 20:17:37 -0500, Chris Burel encoded:
> 2013/1/29 Stefano Sabatini <stefasab at gmail.com>
> > I don't know what you mean by "split up the filter into two separate
> > ones".
> >
> From what I see, the ass video filter currently does 2 things:
> 1. Use libass to render text-based subtitles to images.
> 2. Overlay those subtitles with a video
> Currently, it is a video filter, because it takes in a video stream and
> outputs a video stream, and because there's no subtitle support.  If there
> were subtitle support, those 2 steps could be split into separate filters.
> The first one that renders the subtitles would be a subtitle source filter,
> and the second one would be similar to the video overlay filter, taking in
> one video stream and one subtitle stream (with images already rendered).

What about:

if you need just the subtitles on a background.

But yes in general it should be possible to create a variant or
configure the filter so that it works like a video source.
FFmpeg = Frightening & Foolish Mean Philosophical Educated Geek

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