Fix External subtitle not loading

[arshubham]

Set subtitle directly to pipeline, bypassing clutter-gst. A workaround till clutter-gst is fixed. Timeout is needed since pipeline is reset by setting state to Gst.State.NULL and setting progress just after Gst.State.PLAYING has no effect. A better solution for this is welcome.

Fixes #32 , Fixes #63 , Fixes #57

[ryonakano]

I wonder why ClutterGst.Playback.set_subtitle_uri does not work here, while it works when the app automatically detects a subtitle in the same directory when opening a video file from Files.

[arshubham]

@ryonakano I believe this is because set_subtitle_uri just sets pipeline.set ("suburi", uri, null) without changing the state first. Here I just copied the logic of autoload_subtitle and it worked perfectly.

Edit: Build is failing due to error in npm i -g @elementaryos/houston

[ryonakano]

Now an external subtitle is loaded immediately by dragging and dropping it whether the video is paused or playing, but it's not reflected to the UI; the FileChooserButton external_subtitle_file keeps showing "None".

[ryonakano]

Seem to work.

[jeremypw]

This seems to work well for one film but there is still that crash on starting a new film :-(. I notice that the subtitle file uri is lost if the app is closed then reopened, although it saves the currently playing media. It would be nice to save ands restore the corresponding subtitle uri when they work - but that can be left to another PR. @arshubham are you still working on fixing this PR?

[jeremypw]

There are a number of issues reported about problems playing a second video for some people. This PR may have exacerbated an underlying problem. I'll have a look.

[jeremypw]

@ryonakano I have made a number of improvements to this PR. If you are able to give it some testing that would be great. Thanks.

[ryonakano]

Hmm, the issue @arshubham mentioned seems to be still reproducable for me (not happen in master) if I don't pause the first video.

[jeremypw]

Hmm, I though I tested that - but now I find that with the test .avi video I am using Videos does not crash but becomes unresponsive if i do not pause (OK if video paused before going back). But with another .mkv video I do get a crash. I will look into it further - at least I can now reproduce a crash. Thanks for testing!

[jeremypw]

@ryonakano The last commit fixes the crashes and hangs I was experiencing. Please re-test when you have time :-)

[jeremypw]

Like many Gtk apps this contains signal cascades resulting in hard to diagnose races. It is important that a signal handler ends before triggering another signal - else an Idle loop has to be used.

[ryonakano]

I've tested with a mkv and mp4 file of Elephants Dream (mentioned in #32 (comment)) and the issue that external subtitle is not applied seems to be fixed for me. Playing another video in this way still crashes the app, but it should be another issue like #200.

[jeremypw]

@ryonakano Thanks for testing! So, it looks like my latest changes did not fix the crashing for you then? It seemed to make it pretty stable for me (I may put up a screen capture). But if this crash is also occurring with master then its not a regression and this PR is at least enabling external subtitles to be shown so it may be worth merging anyway.

@danrabbit What do you think?

[jeremypw]

Demonstration of playing external subtitles and switching videos with this PR.

[jeremypw]

It looks like Videos crashes on resume video on machines with an Intel video card, not with an NVidia one. This occurs in master too so is not a regression from this PR.