[gst-devel] gstreamer & libnotify

[Edward Hervey]

On Thu, 2010-08-05 at 09:55 +0300, Stas Gurtovoy wrote:
> Hi,
> 
> I'm new to gstreamer, so maybe I'm doing something totally wrong
> here. 
> I have an SDL application (using SDL for  window, rendering and event
> handling), and I have a thread which uses gstreamer to play a video
> stream. In that thread I initialise the pipeline, create the main loop
> and run it. The video is playing fine on my SDL created window. 
> The problem starts when I get libnotify involved. I use libnotify to
> post some kinds of notifications from the application. The
> notifications are posted from a different thread (not the video player
> thread), and also use glib and libdbus. As soon as a notification is
> shown, the video thread exits (or sometime crashes). 
> 
> 
> Probably there's some collision between libnotify & gstreamer. They do
> have the same context, but the libnotify thread doesn't run his own
> main loop. Here's the trace for the relevant threads: 
> 
> The exiting thread, which run the video main loop:
> 

  Please, don't USE MASSIVELY HUGE FONTS ! In fact, drop the html if
possible.
> 
> ______________________________________________________________________
> 0 0xb6bcac34 in _exit () from /lib/tls/i686/cmov/libc.so.6
> 1 0xb691504d in ?? () from /lib/libdbus-1.so.3
> 2 0xb68f5e73 in ?? () from /lib/libdbus-1.so.3
> 3 0xb68f827b in ?? () from /lib/libdbus-1.so.3
> 4 0xb68f82fd in dbus_connection_send () from /lib/libdbus-1.so.3
> 5 0xb68f162c in ?? () from /lib/libdbus-1.so.3
> 6 0xb68f16a9 in dbus_bus_remove_match () from /lib/libdbus-1.so.3
> 7 0xb692f5db in ?? () from /usr/lib/libdbus-glib-1.so.2
> 8 0xb69311f9 in ?? () from /usr/lib/libdbus-glib-1.so.2
> 9 0xb6fd329f in g_object_run_dispose ()
> from /usr/lib/libgobject-2.0.so.0
> 10 0xb693157b in ?? () from /usr/lib/libdbus-glib-1.so.2
> 11 0xb68f70d5 in dbus_connection_dispatch () from /lib/libdbus-1.so.3
> 12 0xb69286bd in ?? () from /usr/lib/libdbus-glib-1.so.2
> 13 0xb6f41b88 in g_main_context_dispatch ()
> from /usr/lib/libglib-2.0.so.0
> 14 0xb6f450eb in ?? () from /usr/lib/libglib-2.0.so.0
> 15 0xb6f455ba in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
> 16 0x0805135b in vp_thread_func (userdata=0x81b3948) at
> video_player/video_player.c:874
> 17 0xb6c944ff in start_thread ()
> from /lib/tls/i686/cmov/libpthread.so.0
> 18 0xb6c0f5ee in clone () from /lib/tls/i686/cmov/libc.so.6

  this backtrace is useless. Please install debug symbol packages (or
build with debugging symbols enabled and don't strip).

> 
> ______________________________________________________________________
> 
> The frame thread, which calls notify_notification_show:
> 
> 
> ______________________________________________________________________
> 0 0xb690e6b6 in ?? () from /lib/libdbus-1.so.3
> 1 0xb690e09a in ?? () from /lib/libdbus-1.so.3
> 2 0xb690e111 in ?? () from /lib/libdbus-1.so.3
> 3 0xb690bd39 in ?? () from /lib/libdbus-1.so.3
> 4 0xb690c92e in ?? () from /lib/libdbus-1.so.3
> 5 0xb68f6bf8 in ?? () from /lib/libdbus-1.so.3
> 6 0xb68f8d98 in ?? () from /lib/libdbus-1.so.3
> 7 0xb68f8ef2 in ?? () from /lib/libdbus-1.so.3
> 8 0xb69061f1 in dbus_pending_call_block () from /lib/libdbus-1.so.3
> 9 0xb692e1cf in ?? () from /usr/lib/libdbus-glib-1.so.2
> 10 0xb692ec0e in dbus_g_proxy_call ()
> from /usr/lib/libdbus-glib-1.so.2
> 11 0xb77cdb98 in notify_notification_show ()
> from /usr/lib/libnotify.so.1
> 12 0x0804b91d in post_tray_notification (msg=0xb5409008 "Test!") at
> unix_utils.c:277
> 13 0x0804c3a7 in handle_event_msg (msg=0xb46132b4, len=6) at
> scremote_client.c:504
> 14 0x0804ca5e in handle_msg (sock=7) at scremote_client.c:639
> 15 0x0804cb1f in wait_for_msg (sock=7) at scremote_client.c:657
> 16 0x0804dfb5 in frame_thread_func (dummy=0x0) at
> scremote_client.c:1466
> 17 0xb6c944ff in start_thread ()
> from /lib/tls/i686/cmov/libpthread.so.0
> 18 0xb6c0f5ee in clone () from /lib/tls/i686/cmov/libc.so.6
> Here's the code of the video initialisation:

  Same useless backtrace. We don't know what dbus is doing.

  Also, I don't see any usage of GStreamer in those backtraces. How
certain are you the problem is in gstreamer ?

> 
> ******
> 
> static void* vp_thread_func(void* userdata)
> {
> 
>     vp_t* vp = (vp_t*)userdata;
> 
>     vp->thread_state = VP_THREAD_INITIALIZING;
> 
>     if(vp_init(vp)) {
>         vp->thread_state = VP_THREAD_INITIALIZED;
> 
>         vp->loop = g_main_loop_new (NULL , FALSE);
> 
>         // Call our timer function every 500ms - this will be used to
> hide the cursor
>         // when there is no input.
>         g_timeout_add_full(G_PRIORITY_LOW, 500, &vp_timer,
> (gpointer)vp, NULL);
> 
>         syslog(LOG_INFO, "Video player subsystem running.\n");
> 
>         g_main_loop_run(vp->loop);
> 
>         vp_remove(vp);
> 
>         vp->thread_state = VP_THREAD_UNINITIALIZED;
> 
>         if(vp->remove_request) {
>             g_free(vp);
>             // Don't use vp beyond this point.
>         }
>     } else {
>         syslog(LOG_ERR, "Failed to initialize the video player
> subsystem.\n");
>         vp->thread_state = VP_THREAD_INIT_ERROR;
>     }
> 
>     return NULL;
> }
> 
> *****
> 
> Does anyone have an idea what causes the collision? Any suggestions? 
> 
> Thanks,
> Stas.
> 
> 
> 
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