The VideoLAN Forums

Posted: **01 Aug 2018 22:27**

Hello,

I just compiled latest LibVLCKit today for my IOS app and can't resolve a crash problem.

Here is how i get the crash:
Go from Screen A (menu) to Screen B (vlc player) and close Screen B to go back to A.
Repeat this a second time and when back to Screen A, the app crash.

It's a EXC_BAD_ACCESS crash, i guess it try to access closed vlc instance somewhere.

Most of the time i crash in libvlc_MetadataCancel:

Code: Select all

void libvlc_MetadataCancel(libvlc_int_t *libvlc, void *id)
{
    libvlc_priv_t *priv = libvlc_priv(libvlc);

    if (unlikely(priv->parser == NULL))  // <--------- crash here
        return;

    playlist_preparser_Cancel(priv->parser, id);
}

Sometimes it crash in BackgroundWorkerCancel, most of the time in mutex lock line:

Code: Select all

static void BackgroundWorkerCancel( struct background_worker* worker, void* id)
{
    vlc_mutex_lock( &worker->lock );
    for( size_t i = 0; i < vlc_array_count( &worker->tail.data ); )
    {
        struct bg_queued_item* item =
            vlc_array_item_at_index( &worker->tail.data, i );

        if( id == NULL || item->id == id )
        {
            vlc_array_remove( &worker->tail.data, i );
            worker->conf.pf_release( item->entity );
            free( item );
            continue;
        }

        ++i;
    }

    while( ( id == NULL && worker->head.active )
        || ( id != NULL && worker->head.id == id ) )
    {
        worker->head.deadline = VLC_TS_0;
        vlc_cond_signal( &worker->head.worker_wait );
        vlc_cond_signal( &worker->tail.wait );
        vlc_cond_wait( &worker->head.wait, &worker->lock );
    }
    vlc_mutex_unlock( &worker->lock );
}

I use nearly the same code as in the sample Drop in player.
I use this code one time when screen appear:

Code: Select all

_mediaplayer = [[VLCMediaPlayer alloc] initWithOptions:options];

and a bit later the play part:

Code: Select all

[_mediaplayer stop];
    
VLCMedia *media = [[VLCMedia alloc] initWithURL:[NSURL URLWithString:mAdresseComplete]];
    
_mediaplayer.delegate = (id)self;
_mediaplayer.drawable = self.movieView;
    
_mediaplayer.media = media;
[_mediaplayer play];

To stop the player i use this code, i have test with _mediaplayer = nil at the end too without improvements:

Code: Select all

if (_mediaplayer) {
    if (_mediaplayer.media)
        [_mediaplayer stop];
}

While on the player screen, i can stop/resume and switch stream with some buttons but going screen back and fort make it crash.

It's like calling the initWithOptions line again create a second player somewhere and calling stop ask to stop both player but since one no more exist or is stopped, it crash:

I have found that addind _mediaplayer = nil in the stop part and calling the initWithOptions line again create the same crash after calling stop the second time when i stop/resume the player WHILE on the same screen.

Any idea what i do wrong or what is missing to correctly start/stop/kill the VLCMediaPlayer ?

Edit:
I just found if i replace initWithOptions with init, there is no more crash !!!!
Does it come from my options ?

Code: Select all

NSArray* options = @[
	@"--verbose=0", 
        @"--no-interact"
        ];

Edit 2:
No crash with nil as options:

Code: Select all

_mediaplayer = [[VLCMediaPlayer alloc] initWithOptions:nil];

The problem is i need --no-interact

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