GNOME Bugzilla – Bug 675189
[0.11] [matroskademux] Send gap event for subtitle streams
Last modified: 2012-06-19 10:24:17 UTC
Created attachment 213142 [details] [review] Patch Currently the demuxer sends segment events
Suffice it to say this would (only?) make sense if the change is done "system-wide" for other such instances as well (in demuxers, collectpads, etc ?). Btw, should these other instances also include using the gap event as a packet-lost replacement in jitterbuffer (using newsegment up to now for that) ? [nitpick: there is a "Synchornizing" in the patch]
I don't think I can fix this in all gstreamer demuxers, however IIRC the current code that sends segment events in matroska is currently broken anyway, as segment base is always 0.
The handling of the GAP event should at least be implemented in textoverlay (and ideally basesink, at least for prerolling) to make sure that the implementation in matroskademux works at all and makes sense this way. Patching every single demuxer and other element is of course not necessary :)
Guys, this one is actually more important than it seems (possibly applies for other muxers as well), not sending gap event causes the pipeline to stall. Decodebin will not block the subtitle stream on sticky events (because doing that would possible block the stream before allocation query, which is serialized now), so caps and segment event will not block the GstDecodePad. source_pad_blocked_cb in gstdecodebin2 needs a non-sticky event or data to trigger the blocking. Otherwise, if the subtitle pad does not get blocked, other pads will not get exposed.
Yes, I agree that this is really important to fix. Not only in the demuxers but also in sinks and overlay elements (and without changes there sending the events in the demuxer doesn't make a difference anyway)
Sending the event in demuxer makes difference, because without it decodebin gets stuck (as described in previous comment) so you don't even get basic playback working. Also for muxers GstCollectPads probably needs gap support as well.
Comment on attachment 213142 [details] [review] Patch commit c55e492e80e3e9c29c88176dca5759fd86988195 Author: Matej Knopp <matej.knopp@gmail.com> Date: Mon Apr 30 22:59:58 2012 +0200 matroska-demux: Send gap events for subtitle streams