On 4 Mar 2025, at 20:44, Soft Works wrote:
>> -----Original Message----- >> From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of >> Gianluca Cannata >> Sent: Dienstag, 4. März 2025 09:40 >> To: ffmpeg-devel@ffmpeg.org >> Subject: [FFmpeg-devel] GSoC 2025 - OggKate subtitles support >> >> Good morning, >> >> I have to write a karaoke solution with FFmpeg libav libraries for a >> project of mine and I have found OggKate subtitles a good choice to >> implement such solution and I am thinking of writing a Kate demuxer and >> decoder along with a filter that will use OpenGL to render Kate >> subtitles >> capabilities on frame. >> >> What do you think ? >> >> There is someone interested in mentoring this proposal project ? >> >> Or is it too overkill ? >> >> Sincerely >> >> Gianluca >> _______________________________________________ > > > Hi Gianluca, > > while it's true that "OggKate" doesn't appear to be well-known (I've never > heard of it before), but it's also the only officially spec-ed subtitle > format in Ogg containers (besides raw text). > I think that fact makes it interesting to implement it - one could also argue > that the reason why it isn't widespread yet is that ffmpeg doesn't support it > 😊 > > The license of the reference implementation source code appears to be > permissive > (https://github.com/Distrotech/libkate?tab=License-1-ov-file#readme), so an > adaption might be possible as well - yet, IANAL. The official upstream repo for kate is here btw https://gitlab.xiph.org/xiph/kate > > Regarding the effort, I think that the implementation of a renderer is too > steep, especially when aiming to support fancy things like animation. Anyway, > a specific renderer would not quite fit into the ffmpeg architecture, because: > > Every (text) subtitle decoder decodes to ASS format and every (text) subtitle > encoder encodes from ASS to its target format. This means that implementing a > decoder for OggKate would require to translate the Kate format to ASS. > Since we do have an ASS renderer (via libass), it would be still possible to > achieve the goal of rendering those subtitles, even with animations. > > > I have seen that there are two representations of Kate subtitles: A text > format and a bitstream format. What gets muxed into an Ogg container is > always the bitstream format, the text/file format is just an extra and not > needed, so it can be skipped, which means in turn that there's no need for > developing a demuxer. > > As mentioned above, for the format to have a chance to become more > widespread, there would also need to be an encoder. > > Making this a project about developing an encoder+decoder pair for Ogg Kate > would appear to be a nice project IMO. > > sw > > > > > > > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
