[vlc-devel] Libvlc hangs when setting media descriptor in media reached end callback

[Pierre d'Herbemont]

Hi Jacques,

Could you backtrace the running stuck process to see where in vlc it  
does hang?

Pierre.

On Feb 1, 2008, at 2:17 PM, jboileau wrote:

> Hi Pierre,
>
> Have you had a chance to look at this (see description below)? I can  
> download and try the latest build, but wanted to know if anything  
> changed before trying it out. Of course I never rule out that there  
> isn't any problem and that I am just doing things wrong. In that  
> eventuality, let me know if you have any idea on how differently I  
> should do things, I would greatly appreciate. It is a bit  
> problematic for me to not be able to start a new play from inside  
> the media reached end callback.
>
> Thanks for your help,
>
> Jacques Boileau
>
> On Jan 24, 2008 4:14 PM, jboileau <jboileau at gmail.com> wrote:
> Hi Pierre,
>
> Unfortunatly my plan didn't work as well as I had hoped. Here is in  
> a nutshell what I do in the callback now:
>
> I create a new media descriptor (libvlc_media_descriptor_new)
> I add options (libvlc_media_descriptor_add_option)
> I set the descriptor (libvlc_media_instance_set_media_descriptor)
>
> I start the play (libvlc_media_instance_play)
>
> The rest I do once at start up:
>
> I create a media instance  
> (libvlc_media_instance_new_from_media_descriptor)
> I get the event manager (libvlc_media_instance_event_manager)
> I attach to it (libvlc_event_attach)
>
> Now when I am in the event it hangs in the call to  
> libvlc_media_instance_set_media_descriptor. This happens  
> independently if I call from the event or if I post myself a message  
> and do it there! Strange! In an attempt to figure things out I have  
> added a call to libvlc_media_instance_stop prior to calling  
> libvlc_media_instance_set_media_descriptor. This makes things work  
> IF not called directly from the event, otherwise it hangs in  
> libvlc_media_instance_stop.
> Hopefully I have included enough details to help you out.
>
> Jacques Boileau
>
>
> On Jan 24, 2008 1:32 PM, jboileau <jboileau at gmail.com> wrote:
> Hi Pierre,
>
> I just took a closer look at the API and I will try creating a media  
> instance that will be used for the life of my application and use  
> libvlc_media_instance_set_media_descriptor for each new file I play.  
> That way I won't release the media instance from inside my event.  
> This seems like a much better idea. I'll let you know how it turns  
> out.
>
> Jacques
>
> On Jan 24, 2008 9:04 AM, jboileau <jboileau at gmail.com> wrote:
> Hi Pierre,
>
> Well yes the problem is with the release of the media instance and  
> it probably make sense that it hangs there. But I don't know how to  
> do things diffrently. If I need to create a new media descriptor and  
> then get a new media instance from it, if I don't release the  
> previous one won't I end up with memory leaks? Here is what I do in  
> my event callback. Any suggestions on what to do differently for  
> things to work?
>
> I detach from the event manager (libvlc_event_detach)
> I release the media instance (libvlc_media_instance_release)
> --> and it hangs right here as expected <---
> I create a new media descriptor (libvlc_media_descriptor_new)
> I add options (libvlc_media_descriptor_add_option)
> I create a media instance  
> (libvlc_media_instance_new_from_media_descriptor)
> I release the media descriptor (libvlc_media_descriptor_release)
> I get the new event manager (libvlc_media_instance_event_manager)
> I attach to it (libvlc_event_attach)
> I start the play (libvlc_media_instance_play)
>
> I hope this helps you figure things out. Let me know if you need  
> more details.
>
> As always: thanks for your help it is greatly appreciated!
>
> Jacques
>
> On Jan 23, 2008 5:58 PM, Pierre d'Herbemont <pdherbemont at free.fr>  
> wrote:
>
> On Jan 23, 2008, at 10:48 PM, jboileau wrote:
>
>> My reason to do that is to be able to start a new play from inside  
>> the libvlc_MediaInstanceReachedEnd event. I may not be doing things  
>> correctly but presently it simply hangs in my callback. Probably  
>> because I am trying to release something that is probably what is  
>> calling me back! :-) The media descriptor. I have circumvented the  
>> problem by posting myself a message (I am working under Windowzzzz)  
>> and this lets me do what I want since in the handler for this  
>> message I am out of the libvlc_MediaInstanceReachedEnd event  
>> callback. But I would rather not have to resort to this double  
>> callback scheme to get things working.
>
> This is a bit weird cause you shouldn't get issue when releasing the  
> media descriptor in the media_instance callback, unless you are  
> releasing the media instance that currently plays the media  
> descriptor.
>
> Tell me if you encounters more trouble, I'll have a look over the  
> weekend.
>
> Pierre.
>
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