GNOME Bugzilla – Bug 687625
Subtitles (ssa/vobsub) not showing on matroska video with playback-test
Last modified: 2018-11-03 11:22:50 UTC
With 1.0.2 or git master, playback-test never shows any subtitles for the following video: # playback-test 0 http://absolut.zogzog.org/share/samples/mkv/paprika.mkv The video contains 4 subtitle tracks, 1 SSA and 3 VOBSUB. MPlayer, VLC or Gstreamer cannot display the SSA track for some reason, however only Gstreamer fails to display the DVD subtitles. When switching to a DVD subtitle track, the following warning appears and the video freezes: pre-colorspace: not negotiated (gstbasetransform.c(2081): gst_base_transform_handle_buffer (): /GstPlayBin:playbin0/GstPlaySink:playsink/GstBin:tbin/GstSubtitleOverlay:suboverlay/GstVideoConvert:pre-colorspace: not negotiated)
I don't get the not-negotiated error, but instead of subtitles I get some video "artefacts" in the first few lines of the video, at the very top, whenever one would expect subtitles to appear (they disappear when you switch off subs via the checkbox).
The issue I reported is fixed by 5d2d3d90a0 (subtitleoverlay: Return ANY caps for the GET_CAPS query).
There is still an issue with this video on 1.2: the subtitles are displayed correctly at first but once I switch the subtitle track, no subtitle is ever displayed again. It seems the video pad in subtitleoverlay is not unblocked.
Arnaud, is this still an issue with git master? (or latest 1.4) I have a vague memory of the switching having been fixed.
In master it does not work, no subtitle is shown. I'm not sure what's wrong with dvdspu here. The subtitles are shown with my dvdspu branch that uses GstVideoOverlayComposition (see Bug #685282). Unfortunately the subtitles bottom line is clipped: the original dvd video frame had black borders, and originally part of the subtitles was displayed the black borders region. The black borders were cropped during encoding. I'm not sure how to handle this case, I think mplayer just scaled the SPU overlay to match the video frame. We could also move SPU objects to fit them in the video frame, but that's harder to do.
Still an issue with latest git master.
-- GitLab Migration Automatic Message -- This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/76.