Random conversion/save hangs

[David Munch]

Please describe the problem or feature request in detail:

I have on a few occations observed conversion hangs when saving M4Vs, containing subtitles that are being OCR'ed from Blu-ray MKVs.

This occurs at random, and not very often, but it does happen (Around 1 in 50 is my guess). When it occurs, there's a high chance of more than one file failing, although other concurrent saves may continue and finish as expected.

I have only seen multiple file saves to fail together, and often when they are almost complete or practically complete (ie. the load bar has reached the end). Curiously, I can have other saves continue just fine during/after others hang. What I have noticed though, is that those saves that hang together, they are always practically finished or almost finished (80%+ finished), while the remaining that don't hang have much longer to go. Example: I usually do multiple saves at the same time from Blu-ray rips (Main feature + several extras), and it is always some of the extras that hang together, while the main feature finishes correctly some time later (Due to the length/number of strings needed to be OCR'd).

If I try to cancel these hanged saves, the window never closes and I have to quit Subler to remove them.

It does not appear to be the files themselves that are the issue, as I can always open the original MKV's and repeat the file save/OCR without issues.

What are the steps to reproduce this problem:

1. Open MKV files obtained from disc rips in MakeMKV.
2. Check subtitle tracks only.
3. Click the Add button, and save file as protected M4V (Standard save settings).
4. Subler starts OCR'ing as expected.
5. At a random time point the conversion process hangs. The file(s) affected never finish, while others may continue just fine.

What version of Subler you are running: 1.4.1

What operating system version you running

macOS 10.12.6 Sierra

Was there any error message or error dialog, if so please detail or provide screenshots:

None. Just an (often) unfinished conversion/save loading bar.

[Damiano Galassi]

It could be either a deadlock in the OCR code, or some issue in NSDocument. Unfortunately I still have no tracked it down.

[David Munch]

It is really only a minor nuisance since it happens rarely and a simple restart of the app fixes it, but it is of course preferable to fix in the long run. So reel free to hit me with any builds including debug code, if you come across possible culprits in the code, at any point in the future.

[David Munch]

I've noticed that the Window menu shows the • character in front of windows (See screenshot) that are still converting actively. These dots disappear for windows where the progress bar finishes but freezes as explained for this bug. I assume this indicates that the system/Subler is somehow aware that the conversion is done. In case that information is of any help in tracking it down.