Loading a subtitled mkv file while already playing a subtitled mkv file makes the UI freeze

When totem is frozen please open a terminal and run:

  killall -ABRT totem

Now wait a while for a crash report to be written to disk. The totem window should vanish when it's done. Next, send the resulting crash report per these instructions:

  https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment

I used ubuntu-bug as per instructions. The first time ubuntu-bug crashed when I hit the Send button, upon a second attempt it might have been successful, but I'm not sure. The ubuntu-bug window closed immediately when I hit Send, without feedback from either from the ubuntu-bug UI or in the terminal. I'm not sure if the information can find its way to this particular bug report given that I was never asked to specify where it belongs. This is all rather confusing.

Upon further testing of Totem, I have discovered that what's triggering the issue is the subtitles being turned off. Simply open a file, turn the subtitles off, and try to load a new file. No need to wait.

Please follow all the instructions in:

  https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment

and tell us what you find.

Actually, this might be what you're looking for? The timestamp seems off though.

https://errors.ubuntu.com/oops/5303ab96-6c83-11e9-92de-fa163e6cac46

That's certainly one totem crash, thanks :)

Unfortunately that one doesn't seem to be readable/retraceable. So please try repeating with more freezes and forced crashes.

Five more:

https://errors.ubuntu.com/oops/623580d8-6ce1-11e9-92e7-fa163e6cac46
https://errors.ubuntu.com/oops/9b34123e-6ce2-11e9-a7d7-fa163ee63de6
https://errors.ubuntu.com/oops/94ee6720-6ce3-11e9-92e7-fa163e6cac46
https://errors.ubuntu.com/oops/60a9d2e4-6ce6-11e9-92e7-fa163e6cac46
https://errors.ubuntu.com/oops/525dc2cc-6ce8-11e9-92e7-fa163e6cac46

Could you add a video example to the bug maybe?

Those reports don't have useful stacktrace, could you try to get one following the steps on https://wiki.ubuntu.com/Backtrace#Already_running_programs

Note that the journal one one of those include totem warnings

'gst_caps_get_size: assertion 'GST_IS_CAPS (caps)' failed
gst_mini_object_unref: assertion 'mini_object != NULL' failed
gst_pad_set_caps: assertion 'caps != NULL && gst_caps_is_fixed (caps)' failed'

Hopefully I'm adding the attachment correctly, and hopefully it contains some useful information.

I was unable to follow the instructions exactly as gdb would hang when pressing ctrl+c. I waited at least ten minutes but the prompt wouldn't appear. I had to kill totem outside of gdb to progress to where I could type in the backtrace command. Further, while the wiki suggests sudo should only be necessary for programs run with sudo, I was unable to attach the totem process without it. So that's what I did.

the backtrace is not really that useful since it lacks debug symbols

Did you get any file in /var/crash following Daniel's recommendations?

errors.ubuntu.com is timing out again today so I am unable to review the links in comment #7.

Yes Sebastien, a .crash file appears in /var/crash/ if I killall -ABRT totem.

However, as there's so much talk of crashing, I want to stress that the entire program has not crashed. It still listens, and obeys, a click on the close button. I just noticed that you can even navigate the UI and even load a new (not subtitled) file and it'll play.

The issue comes from playing one subtitled video, trying to load a new (or the same) subtitled video, and the video portion of the UI getting stuck and the video not playing.

In previous versions of Ubuntu, trying this meant a full crash. Clicking the close button led to a wait for the force quit option. But now in 19.04, the program is alive. It just can't play the video. It's not an issue of the video being paused either, clicking the play/pause button does nothing and the seek bar can't be interacted with.

Added a gst-plugins-good1.0 task, assuming the problem is related to /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstmatroska.so

Thanks, it looks like it's neither new nor a regression then (in the sense of something that used to work and stopped). Ideally having an example would make easier to test/work on the issue but I guess most of subtitled videos are non free content and can't be easily shared here?

Here's a sample video I found that I assume is OK to share a link to. Just open it, turn subtitles off, and finally open the same file in the same Totem window.

https://github.com/Matroska-Org/matroska-test-files/blob/master/test_files/test5.mkv

Reported upstream on https://gitlab.gnome.org/GNOME/totem/issues/323