Crash when setting media in libvlc_MetadataRequest

changed the description

I can confirm that I has the same trouble

So I've spent A TON of time trying to fix a very similar issue. You guys might be hitting the same thing...

The bottom line is that there's some internal mutexes in VLCLibrary that clash when there's 2 VLCLibraries in play. I can get vlc to crash more or less consistently by opening one stream, closing, opening the second stream and then on close this crash happens.

But there shouldn't be 2 of those in play, right? Well I though so, but then I figured out that I was initing VLCMediaListPlayer with _listPlayer = [[VLCMediaListPlayer alloc] initWithOptions:options andDrawable:_actualVideoOutputView]; and with initWithOptions: somehow causes this to init new VLCLibrary every time thus causing the issue.

Swapping that init with _listPlayer = [[VLCMediaListPlayer alloc] initWithDrawable:_actualVideoOutputView]; magically made the problem disappear, because now there's only one VLCLibrary in play.

Although this does not fix the underlying mutex issue (which I could not trace back, it's way above my pay grade), it did fix the crash that plagued me for the past 3 months.

Exactly, I have been using a singleton instance of VLCMediaPlayer as a workaround:

extension VLCMediaPlayer {
    public static let shared: VLCMediaPlayer = {
        let options: [String] = [
            "--no-audio",
            "--avcodec-hurry-up",
            "--avcodec-fast",
            "--avcodec-dr"
            ]
        
        let player: VLCMediaPlayer = VLCMediaPlayer(options: options)
        #if DEBUG
            player.libraryInstance.debugLogging = true
        #endif
        
        return player
    }()
}

class PlayerViewController: UIViewController {
    let player: VLCMediaPlayer = VLCMediaPlayer.shared
}

mentioned in issue vlc-ios#132 (closed)

mentioned in issue #167 (closed)

changed milestone to %3.1.3

See #167 (closed), same crash.

Please provide a full backtrace.

@jbk you want a full backtrace of this issue happening?

I can try to replicate this later today, but you can also easily replicate this - in VLC, open VLCPlaybackController and in line 192 add initWithOptions:@[]

The line becomes something like _listPlayer = [[VLCMediaListPlayer alloc] initWithOptions:@[] andDrawable:_actualVideoOutputView];

(you can also trigger this in VLC if you can trigger the "external subtitle file", which is rare - this is what I reported in vlc-ios#132 (closed) )

Then you just need to start vlc and open at least 2 files, at the end of closing the second one you should get the crash.

This is a stack trace from the simulator (which also crashes like on a real device), done using the instructions above.

(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x000000011054ad62 VLC for iOS`background_worker_Push(worker=0x0103840fdb854808, entity=0x00007f9d1d21d830, id=0x00007f9d1d219a60, timeout=-1) at background_worker.c:218 [opt]
    frame #1: 0x00000001105008a9 VLC for iOS`playlist_preparser_Push(preparser=0x000000011c7ee795, item=0x00007f9d1d21d830, i_options=META_REQUEST_OPTION_SCOPE_LOCAL, timeout=-1, id=0x00007f9d1d219a60) at preparser.c:178 [opt]
    frame #2: 0x00000001104e468d VLC for iOS`libvlc_MetadataRequest(libvlc=0x000000011c8412e0, item=0x00007f9d1d21d830, i_options=META_REQUEST_OPTION_SCOPE_LOCAL, timeout=-1, id=0x00007f9d1d219a60) at libvlc.c:509 [opt]
    frame #3: 0x00000001104dbf49 VLC for iOS`media_parse(media=0x00007f9d1d219a60, b_async=<unavailable>, parse_flag=<unavailable>, timeout=-1) at media.c:811 [opt]
    frame #4: 0x00000001104dc023 VLC for iOS`libvlc_media_parse_with_options(media=<unavailable>, parse_flag=<unavailable>, timeout=<unavailable>) at media.c:854 [opt]
    frame #5: 0x000000010fd63bd9 VLC for iOS`-[VLCPlaybackController startPlayback](self=0x000060c00019c630, _cmd="startPlayback") at VLCPlaybackController.m:213
    frame #6: 0x000000010fd633ae VLC for iOS`-[VLCPlaybackController playMediaList:firstIndex:subtitlesFilePath:](self=0x000060c00019c630, _cmd="playMediaList:firstIndex:subtitlesFilePath:", mediaList=0x000060c000444860, index=0, subsFilePath=0x0000000000000000) at VLCPlaybackController.m:154
    frame #7: 0x000000010fd90a90 VLC for iOS`-[VLCPlaybackController(self=0x000060c00019c630, _cmd="configureMediaList:atIndex:", list=0x000060c000444860, index=0) configureMediaList:atIndex:] at VLCPlaybackController+MediaLibrary.m:135
    frame #8: 0x000000010fd909e2 VLC for iOS`-[VLCPlaybackController(self=0x000060c00019c630, _cmd="configureMediaListWithFiles:indexToPlay:", files=@"1 element", index=0) configureMediaListWithFiles:indexToPlay:] at VLCPlaybackController+MediaLibrary.m:130
    frame #9: 0x000000010fd8fc4c VLC for iOS`-[VLCPlaybackController(self=0x000060c00019c630, _cmd="configureWithFile:", file=0x0000604000293470) configureWithFile:] at VLCPlaybackController+MediaLibrary.m:74
    frame #10: 0x000000010fd8f76f VLC for iOS`-[VLCPlaybackController(self=0x000060c00019c630, _cmd="playMediaLibraryObject:", mediaObject=0x0000604000293470) playMediaLibraryObject:] at VLCPlaybackController+MediaLibrary.m:29
    frame #11: 0x000000010fe7d1ef VLC for iOS`VLCTabbarCooordinator.playMedia(media=0x0000604000293470, self=0x0000608000051280) at VLCTabBarCoordinator.swift:108
    frame #12: 0x000000010fe7d13e VLC for iOS`VLCTabbarCooordinator.mediaViewControllerDidSelectMediaObject(viewcontroller=0x00007f9d1d215fb0, mediaObject=0x0000604000293470, self=0x0000608000051280) at VLCTabBarCoordinator.swift:102
    frame #13: 0x000000010fe7d43e VLC for iOS`protocol witness for VLCMediaViewControllerDelegate.mediaViewControllerDidSelectMediaObject(_:mediaObject:) in conformance VLCTabbarCooordinator at VLCTabBarCoordinator.swift:0
    frame #14: 0x000000010fe616d2 VLC for iOS`VLCMediaViewController.collectionView(collectionView=0x00007f9d1e059200, indexPath=2 indices, self=0x00007f9d1d215fb0) at MediaViewController.swift:179
    frame #15: 0x000000010fe6179c VLC for iOS`@objc VLCMediaViewController.collectionView(_:didSelectItemAt:) at MediaViewController.swift:0
    frame #16: 0x00000001180331fa UIKit`-[UICollectionView _selectItemAtIndexPath:animated:scrollPosition:notifyDelegate:] + 702
    frame #17: 0x000000011805f3a9 UIKit`-[UICollectionView touchesEnded:withEvent:] + 594
    frame #18: 0x00000001177a2767 UIKit`forwardTouchMethod + 340
    frame #19: 0x00000001177a2831 UIKit`-[UIResponder touchesEnded:withEvent:] + 49
    frame #20: 0x00000001177a2767 UIKit`forwardTouchMethod + 340
    frame #21: 0x00000001177a2831 UIKit`-[UIResponder touchesEnded:withEvent:] + 49
    frame #22: 0x0000000117b5dfbc UIKit`_UIGestureEnvironmentSortAndSendDelayedTouches + 5525
    frame #23: 0x0000000117b57ed5 UIKit`_UIGestureEnvironmentUpdate + 1506
    frame #24: 0x0000000117b578a7 UIKit`-[UIGestureEnvironment _deliverEvent:toGestureRecognizers:usingBlock:] + 484
    frame #25: 0x0000000117b569a9 UIKit`-[UIGestureEnvironment _updateGesturesForEvent:window:] + 281
    frame #26: 0x00000001175ec7ab UIKit`-[UIWindow sendEvent:] + 4064
    frame #27: 0x0000000117590310 UIKit`-[UIApplication sendEvent:] + 352
    frame #28: 0x0000000117ed16af UIKit`__dispatchPreprocessedEventFromEventQueue + 2796
    frame #29: 0x0000000117ed42c4 UIKit`__handleEventQueueInternal + 5949
    frame #30: 0x000000011b10abb1 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
    frame #31: 0x000000011b0ef4af CoreFoundation`__CFRunLoopDoSources0 + 271
    frame #32: 0x000000011b0eea6f CoreFoundation`__CFRunLoopRun + 1263
    frame #33: 0x000000011b0ee30b CoreFoundation`CFRunLoopRunSpecific + 635
    frame #34: 0x000000011df0fa73 GraphicsServices`GSEventRunModal + 62
    frame #35: 0x0000000117575057 UIKit`UIApplicationMain + 159
    frame #36: 0x000000010fdca5ef VLC for iOS`main(argc=1, argv=0x00007ffedfebf098) at main.m:20
    frame #37: 0x000000011c868955 libdyld.dylib`start + 1
    frame #38: 0x000000011c868955 libdyld.dylib`start + 1

Weird

changed milestone to %3.1.4

added Blocker label

changed milestone to %Future

Post-poned as 3.1.4 is out.

Please send a new backtrace with 3.3.0.

Crash when setting media in libvlc_MetadataRequest

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