The VideoLAN Forums

Posted: **01 Aug 2012 10:51**

Hi there,
i am using 2.x libvlc version and want to use vlm functionality to stream "sheduled" streams (udp, rtp protocols). But i end up with strange problems such a blocking in libvlc_vlm_stop_media or in some more certain libvlc_vlm_* functions in my own libvlc_VlmMediaInstanceStatusEnd event callback. What i want is actually just to stop current streaming in any time, or continue streaming another file when current one is finished. I need some decent libvlc_vlm_* usage examples or just advices to find out what i am doing wrong. To clear out my actual problem i provide some code examples:

Registering event handler:

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eventManager = libvlc_vlm_get_event_manager(vlc);
libvlc_event_attach(eventManager, libvlc_VlmMediaInstanceStatusEnd, vlcEventHandler, NULL);

My event callback

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void vlcEventHandler(const struct libvlc_event_t * evt, void * data)
{
	printf("stream end?\n");

    int ret = libvlc_vlm_stop_media(vlc, "media_name");
    PINFO("Returned: %d", ret); // it does not print, prints -1 when media_name is faked one
    //int ret = libvlc_vlm_set_input(vlc, "media_name", "/home/algirdas/dev/live555/adstreamer/big_buck_bunny_1080p_surround.ts"); blocks here again

    //PINFO("Return value: %d", ret);
    //ret = libvlc_vlm_play_media(vlc, "media_name");  blocks here too
    //PINFO("Return value: %d", ret);
}

Streaming (playing)

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libvlc_vlm_play_media(vlc, "media_name");

After *_play_media() call i use

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while (1) {
sleep(1);
}

Thanks!

Posted: **01 Aug 2012 22:48**

To be honest, I wouldn't be surprised if the libvlc_vlm code to have some internal issues.

Posted: **01 Aug 2012 23:05**

Seriously, for scheduling, you may be better off implementing the timer in your application. You can use a normal LibVLC media player object then.

The VLM API is a bitch, if I may say.

Posted: **02 Aug 2012 08:52**

Seriously, for scheduling, you may be better off implementing the timer in your application. You can use a normal LibVLC media player object then.

Huh? It is not about playback, it is about streaming to network or maybe libvlc_media_player_* module has streaming ability too which i did not notice. Can anyone give just simple streaming without VLM example to start with?

Posted: **02 Aug 2012 09:02**

It's the same. You need to set the input path, the sout options, etc.

The only component that, alas, can currently really only be reached through VLM is RTSP VoD.

Posted: **02 Aug 2012 09:21**

Thanks for your answers. So it depends only on sout i guess, i will try to read docs about it, thanks again. Will write here when i fail again

Posted: **02 Aug 2012 15:06**

Ok, i got same problem about blocking as i said about from the start. Now all VLM functions are removed. I extracted my other code and tested vlc-only. Wrote my problems in code as comments. There it is:

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#include <vlc/libvlc.h>
#include <vlc/libvlc_media.h>
#include <vlc/libvlc_media_player.h>
#include <vlc/libvlc_events.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>

#define PERROR(x,...)     printf("ERROR:   (%s) "x"\n", __func__, ##__VA_ARGS__)
#define PWARNING(x,...)   printf("WARNING: (%s) "x"\n", __func__, ##__VA_ARGS__)
#define PINFO(x,...)      printf("INFO:    (%s) "x"\n", __func__, ##__VA_ARGS__)

static int streaming = 1;
static libvlc_instance_t *vlc;
static libvlc_media_player_t *mediaPlayer;

void vlcEventHandler(const struct libvlc_event_t * evt, void * data)
{
    PINFO("stream end? %x", mediaPlayer);

    libvlc_media_t *m = libvlc_media_new_path(vlc, "movie_next.ts");

    // PROBLEM: blocks from here
    libvlc_media_player_stop(mediaPlayer);
    libvlc_media_player_set_media(mediaPlayer, m);
    libvlc_media_player_play(mediaPlayer);

    PINFO("Does not reach here");
}

int main(int argc, char * argv[])
{
    const char * sout = "--sout #std{access=udp,mux=ts,dst=239.1.1.2}";
    const char * const vlcArgs[] = {
        "-I", "dummy",
        "--ignore-config",
        "--extraintf=logger",
        "--verbose=0",
        "--sout-all",
        "--sout", "#std{access=udp,mux=ts,dst=239.1.1.2}",
        "--sout-keep",
        "--no-skip-frames",
        "--no-drop-late-frames",
        "vlclog.log"
    };
    const char * url = "movie1.ts";

    libvlc_event_manager_t *eventManager;

    // VLC main job
    vlc = libvlc_new(sizeof(vlcArgs)/sizeof(vlcArgs[0]), (const char * const*)vlcArgs);

    libvlc_media_t *m = libvlc_media_new_path(vlc, url);
    libvlc_media_add_option(m, sout);     // ANOTHER PROBLEM: this one is not working either, how to add whole sout line by this method? I need it for more dynamic use
    mediaPlayer = libvlc_media_player_new_from_media(m);

    libvlc_media_release(m);

    // events
    eventManager = libvlc_media_player_event_manager(mediaPlayer);
    libvlc_event_attach(eventManager, libvlc_MediaPlayerEndReached, vlcEventHandler, NULL);

    libvlc_media_player_play(mediaPlayer);

    PINFO("Entering loop");

    while (streaming) {
        sleep(1);
    }

    PINFO("Exiting loop..");
}

Posted: **02 Aug 2012 15:31**

Controlling LibVLC from its own event callback is going to deadlock. No big surprises there.

Posted: **02 Aug 2012 15:37**

Oh, i understand now, but... how to avoid it? It seems i need to add more logics here, like set some extra vars and change player's state in some other places but not in event callbacks. Thanks. Btw, can i add sout line with libvlc_media_add_option() or it can be used only when creating vlc instance?

Posted: **02 Aug 2012 19:33**

Oh, i understand now, but... how to avoid it?

I simply send all the events I receive via the callback to a background thread. That other thread can serialise all the events and safely call back into libvlc.

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