Hi, I am looking for some guidance regarding future plans about processing subtitle streams in filter graphs.
Please correct me where I'm wrong - this is the situation as I've understood it so far: - Currently, ffmpeg filter graphs do not support processing subtitle streams - This is why filters like 'subtitles' and 'ass' need to open, read and parse the media file a second time in parallel instead of just taking the subtitle events from ffmpeg'demuxing - For graphical subtitles, there exists the so-called 'sub2video' workaround which is injecting the the graphical subtitle overlay images into the video filtergraph by declaring them as video - The 'sub2video' was meant to exist until filtering would support subtitle streams - A while ago, Clement Boesch submitted a patch for adding subtitle streams to filtergraph processing (https://patchwork.ffmpeg.org/project/ffmpeg/patch/20161102220934.26010-...@pkh.me/) - I read through all the discussion about it, but nothing happened afterwards and I couldn't find any indication about why it didn't get merged I'm asking because I'm intending to implement a subtitle filter that operates on in-stream data rather than a separate input and that will render text on transparent frames for later overlay. The possible options that I have identified so far for creating that kind of "subtitle rendering filter" would be: - Create a video source filter and implement some hack to get the subtitle data from the decoder to that filter - or... - Jump on the sub2video implementation and extend it to render overlay images in case of text subtitles - or... - check out the situation with regards to adding subtitle filter support in ffmpeg and ask about plans for this That's where I stand right now. Does it even make sense, the way I summarized it?` Thank you very much, softworkz . _______________________________________________ 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".
