The VideoLAN Forums

Posted: **01 Mar 2015 15:14**

Hello!
I use my own little player based on VLC and written on C# on windows: https://github.com/sibvic/watchitonce
I've tried to show the current time on the video (using marguee) and it look like LibVLC crashes when I call libvlc_video_get_marquee_int
libvlc_video_set_marquee_int works fine.

[DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)]
public static extern int libvlc_video_get_marquee_int(IntPtr p_mi, libvlc_video_marquee_option_t option);

I do pass into the p_mi a valid player handle and 0 as an option and get this error:
An unhandled exception of type 'System.AccessViolationException' occurred in LibVlcWrapper.dll
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

I can't figure out why I get this error. Everything else works fine. Is there any way to turn some king of libvlc logging on?
How can II figure out why it's crashing without compiling the libvlc by myself? I'm a C++ developer but it's pretty hard to compile libvlc on Windows so I hope I can avoid this.

I use libvlc.dll from VLC player v.2.1.2

Posted: **01 Mar 2015 15:56**

Can you share a backtrace? And use 2.2.0 ?

Btw, compiling libVLC on Windows is not that hard anymore.

Posted: **07 Mar 2015 11:59**

I've try the 2.2.0 but without any luck.
The call stack looks like this (2.2.0):

Code: Select all

>	libvlccore.dll!69af4e69()	Unknown
 	[Frames below may be incorrect and/or missing, no symbols loaded for libvlccore.dll]	
 	libvlc.dll!69e1756e()	Unknown
 	[Managed to Native Transition]	
 	LibVlcWrapper.dll!Implementation.Filters.MarqueeFilter.GetMarquee(LibVlcWrapper.libvlc_video_marquee_option_t option) Line 159	C#

I'm more sure weather it will help you.
I'm still struggling to build it using msys for windows, but if I'll get it compiled then I'll try to repeat the crash on the debug build and provide more detailed information.
P.S. Sorry for the late response, I do time to experiment with VLC only on weekends.

Posted: **07 Mar 2015 12:47**

You need to create a full backtrace under gdb

Posted: **07 Mar 2015 13:41**

You need to create a full backtrace under gdb

Code: Select all

Program received signal SIGSEGV, Segmentation fault.                                                      
0x69874e69 in vlc_object_release () from Q:\projects\watchitonce\WaitchItOnce\bin\Debug\libvlccore.dll    
(gdb) bt                                                                                                  
#0  0x69874e69 in vlc_object_release () from Q:\projects\watchitonce\WaitchItOnce\bin\Debug\libvlccore.dll
(gdb)

Like this one?

Posted: **07 Mar 2015 16:11**

Yes, but this one is a bit short

Do you have logs?

Posted: **09 Mar 2015 17:44**

I don't have logs, but finally... after a bit of source editing (there was several compilation errors, not sure whether it's mine enviroment or broken Windows build) I managed to build the VLC and crash dissapears. Maybe the bug is fixed or maybe it is a bad windows build.

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Crash on libvlc_video_get_marquee_int call

Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call

Re: Crash on libvlc_video_get_marquee_int call