Difference between revisions of "LibVLC SampleCode Thumbnailer"

From VideoLAN Wiki
Jump to navigation Jump to search
m (+{{Lowercase}})
 
(2 intermediate revisions by 2 users not shown)
Line 1: Line 1:
This sample code will generate a thumbnail from any media.
+
{{Lowercase}}
 +
Moved [http://git.videolan.org/?p=vlc.git;a=blob;f=doc/libvlc/vlc-thumb.c].
  
Using VLC 1.2 API (libvlc 5.1.0), last updated 2011, May 14th.
+
[[Category:libVLC]]
 
 
It can be used by nautilus instead of totem-video-thumbnailer
 
  /* Copyright [[User:Funman|Rafaël Carré]] (licence [http://en.wikipedia.org/wiki/WTFPL WTFPL]) */
 
<pre>/* A video thumbnailer compatible with nautilus */
 
/* Copyright © 2007-2011 Rafaël Carré <funman@videolanorg> */
 
 
 
/* Works with : libvlc 1.2.0
 
  gcc -pedantic -Wall -Werror -Wextra `pkg-config --cflags --libs libvlc`
 
 
 
  # to register the thumbnailer:
 
  list=`grep ^Mime vlc.desktop|cut -d= -f2-|sed -e s/";"/\\\n/g -e s,/,@,g`
 
  vid=`echo $mimes|grep ^vid`
 
  for i in $vid
 
  do
 
    key=/desktop/gnome/thumbnailers/$i/enable
 
    gconftool-2 -t boolean -s $key true
 
    gconftool-2 -t string  -s $key "vlc-thumb -s %s %u %o"
 
  done
 
*/
 
 
 
#include <assert.h>
 
#include <stdio.h>
 
#include <stdlib.h>
 
#include <string.h>
 
#include <unistd.h>
 
#include <locale.h>
 
 
 
#include <vlc/vlc.h>
 
 
 
/* position at which the snapshot is taken */
 
#define VLC_THUMBNAIL_POSITION (30./100.)
 
 
 
static void usage(const char *name, int ret)
 
{
 
    fprintf(stderr, "Usage: %s [-s width] <video> <output.png>\n", name);
 
    exit(ret);
 
}
 
 
 
/* extracts options from command line */
 
static void cmdline(int argc, const char **argv, const char **in,
 
                    char **out, char **out_with_ext, int *w)
 
{
 
    int idx = 1;
 
    size_t len;
 
 
 
    if (argc != 3 && argc != 5)
 
        usage(argv[0], argc != 2 || strcmp(argv[1], "-h"));
 
 
 
    *w = 0;
 
 
 
    if (argc == 5) {
 
        if (strcmp(argv[1], "-s"))
 
            usage(argv[0], 1);
 
 
 
        idx += 2; /* skip "-s width" */
 
        *w = atoi(argv[2]);
 
    }
 
 
 
    *in  = argv[idx++];
 
    *out = strdup(argv[idx++]);
 
    assert(*out);
 
 
 
    len = strlen(*out);
 
    if (len >= 4 && !strcmp(*out + len - 4, ".png")) {
 
        *out_with_ext = *out;
 
        return;
 
    }
 
 
 
    /* We need to add .png extension to filename,
 
    * VLC relies on it to detect output format,
 
    * and nautilus doesn't give filenames ending in .png */
 
 
 
    *out_with_ext = malloc(len + sizeof ".png");
 
    assert(*out_with_ext);
 
    strcpy(*out_with_ext, *out);
 
    strcat(*out_with_ext, ".png");
 
}
 
 
 
static libvlc_instance_t *create_libvlc(void)
 
{
 
    static const char* const args[] = {
 
        "--intf", "dummy",                  /* no interface                  */
 
        "--vout", "dummy",                  /* we don't want video (output)  */
 
        "--no-audio",                      /* we don't want audio (decoding) */
 
        "--no-video-title-show",            /* nor the filename displayed    */
 
        "--no-stats",                      /* no stats                      */
 
        "--no-sub-autodetect-file",        /* we don't want subtitles        */
 
        "--no-inhibit",                    /* we don't want interfaces      */
 
        "--no-disable-screensaver",        /* we don't want interfaces      */
 
        "--no-snapshot-preview",            /* no blending in dummy vout      */
 
#if 1
 
        "--verbose=2",                      /* full log                      */
 
#endif
 
    };
 
 
 
    return libvlc_new(sizeof args / sizeof *args, args);
 
}
 
 
 
static void callback(const libvlc_event_t *ev, void *param)
 
{
 
    float new_position = ev->u.media_player_position_changed.new_position;
 
 
 
    switch (ev->type) {
 
 
 
    case libvlc_MediaPlayerPositionChanged:
 
        if (new_position >= VLC_THUMBNAIL_POSITION * .9) { /* 90% margin */
 
            *(int*)param = 1;
 
        }
 
        break;
 
    case libvlc_MediaPlayerSnapshotTaken:
 
        *(int*)param = 1;
 
        break;
 
 
 
    default:
 
        assert(0);
 
    }
 
}
 
 
 
/* FIXME: should use pthread notification */
 
static void event_wait(const char *error, int *f)
 
{
 
#define VLC_THUMBNAIL_TIMEOUT  5.0 /* 5 secs */
 
#define VLC_THUMBNAIL_LOOP_STEP 0.2 /* 200 ms */
 
 
 
    float max = VLC_THUMBNAIL_TIMEOUT;
 
    while ((max -= VLC_THUMBNAIL_LOOP_STEP) > 0.) {
 
        if (*f)
 
            return;
 
 
 
        usleep(VLC_THUMBNAIL_LOOP_STEP * 1000000);
 
    }
 
 
 
    fprintf(stderr,
 
            "%s (timeout after %.2f secs!\n", error, VLC_THUMBNAIL_TIMEOUT);
 
    exit(1);
 
}
 
 
 
static void set_position(libvlc_media_player_t *mp)
 
{
 
    int f = 0;
 
    libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 
    assert(em);
 
 
 
    libvlc_event_attach(em, libvlc_MediaPlayerPositionChanged, callback, &f);
 
    libvlc_media_player_set_position(mp, VLC_THUMBNAIL_POSITION);
 
    event_wait("Couldn't set position", &f);
 
    libvlc_event_detach(em, libvlc_MediaPlayerPositionChanged, callback, &f);
 
}
 
 
 
static void snapshot(libvlc_media_player_t *mp, int width, char *out_with_ext)
 
{
 
    int f = 0;
 
    libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 
    assert(em);
 
 
 
    libvlc_event_attach(em, libvlc_MediaPlayerSnapshotTaken, callback, &f);
 
    libvlc_video_take_snapshot(mp, 0, out_with_ext, width, 0);
 
    event_wait("Snapshot has not been written", &f);
 
    libvlc_event_detach(em, libvlc_MediaPlayerSnapshotTaken, callback, &f);
 
}
 
 
 
int main(int argc, const char **argv)
 
{
 
    const char *in;
 
    char *out, *out_with_ext;
 
    int width;
 
    libvlc_instance_t *libvlc;
 
    libvlc_media_player_t *mp;
 
    libvlc_media_t *m;
 
 
 
    /* mandatory to support UTF-8 filenames (provided the locale is well set)*/
 
    setlocale(LC_ALL, getenv("LANG"));
 
 
 
    cmdline(argc, argv, &in, &out, &out_with_ext, &width);
 
 
 
    /* starts vlc */
 
    libvlc = create_libvlc();
 
    assert(libvlc);
 
 
 
    m = libvlc_media_new_path(libvlc, in);
 
    assert(m);
 
 
 
    mp = libvlc_media_player_new_from_media(m);
 
    assert(mp);
 
 
 
    libvlc_media_player_play(mp);
 
 
 
    /* takes snapshot */
 
    set_position(mp);
 
    snapshot(mp, width, out_with_ext);
 
 
 
    libvlc_media_player_stop(mp);
 
 
 
    /* clean up */
 
    if (out != out_with_ext) {
 
        rename(out_with_ext, out);
 
        free(out_with_ext);
 
    }
 
    free(out);
 
 
 
    libvlc_media_player_release(mp);
 
    libvlc_media_release(m);
 
    libvlc_release(libvlc);
 
 
 
    return 0;
 
}</pre>
 

Latest revision as of 08:35, 4 March 2019

Moved [1].