GNOME Bugzilla – Bug 653493
Add CDG demuxing/decoding support
Last modified: 2018-11-03 12:55:36 UTC
Using ggst-ffmpeg 0.10.11 and gst 0.10.32. I am using a sample from: http://www.powerkaraoke.com/download/NobodyKnowsYou.cdg Totem is unable to open it. I attempted to write a gst-launch pipeline and that yielded an Internal Data Error. I used: gst-launch-0.10 --gst-debug ffmpeg:5 filesrc location=/tmp/NobodyKnowsYou.cdg ! ffdemux_cdg ! ffdec_cdgraphics ! ximagesink The error seems to be coming from gst_ffmpegdata_peek which claims it is pulling 21600 bytes then fails with "Got -3 (unexpected) return result 0".
The CDG demuxer was recently disabled because it has never worked. Marking as enhancement.
(In reply to comment #1) > The CDG demuxer was recently disabled because it has never worked. Marking as > enhancement. I'd be interested trying to work on this. Could you please point me the commit disabling it? I didn't manage to find it.
Looking at ./gst-libs/ext/libav/libavformat/cdg.c ffmpeg doesn't seem to do much demuxing; am I right? Would be better/easier to write a gst element implementing a cdg demuxer from scratch rather than using ffmpeg?
(In reply to comment #3) > Looking at ./gst-libs/ext/libav/libavformat/cdg.c ffmpeg doesn't seem to do > much demuxing; am I right? Hum actually I think it does. So what we need to is to get the decoder working with gst.
Thanks to Olivier I finally managed to get this working! I had to patch ffmpeg to get it working but I'm not sure if that's the proper fix.
Created attachment 198738 [details] [review] Add CDG support
Created attachment 198739 [details] [review] cdg.c: set AV_PKT_FLAG_KEY flag
Review of attachment 198739 [details] [review]: Please submit this patch to libav, we'll pick the proper checkout once it's in there.
Other patch looks ok
(In reply to comment #8) > Review of attachment 198739 [details] [review]: > > Please submit this patch to libav, we'll pick the proper checkout once it's in > there. Sure, but I wanted to have your advice on it first; it's not like I'm really understanding any of this. :)
(In reply to comment #8) > Review of attachment 198739 [details] [review]: > > Please submit this patch to libav, we'll pick the proper checkout once it's in > there. I opened https://ffmpeg.org/trac/ffmpeg/ticket/543
Also reported to http://bugzilla.libav.org/show_bug.cgi?id=55
Any news here?
I'm not planning to work further on this in the near future so feel free to take it over.
Not planning to take it over, just wondering if there's still interest or if we should just close this
Well, I still think CDG support in GStreamer would be good.
Sure, would be nice to have. But keeping a feature request open for something nobody is interested to implement is not very useful :)
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