doc/libvlc/vlc-thumb.c

   1 /* Copyright Rafaël Carré (licence WTFPL) */
   2 /* A video thumbnailer compatible with nautilus */
   3 /* Copyright © 2007-2011 Rafaël Carré <funman@videolanorg> */
   4
   5 /* Works with : libvlc 1.2.0
   6    gcc -pedantic -Wall -Werror -Wextra `pkg-config --cflags --libs libvlc` -lpthread
   7
   8   # to register the thumbnailer:
   9   list=`grep ^Mime vlc.desktop|cut -d= -f2-|sed -e s/";"/\\\n/g -e s,/,@,g`
  10   vid=`echo $mimes|grep ^vid`
  11   for i in $vid
  12   do
  13     key=/desktop/gnome/thumbnailers/$i/enable
  14     gconftool-2 -t boolean -s $key true
  15     gconftool-2 -t string  -s $key "vlc-thumb -s %s %u %o"
  16   done
  17  */
  18
  19 #include <assert.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <locale.h>
  25 #include <pthread.h>
  26 #include <errno.h>
  27 #include <time.h>
  28
  29 #if !defined (_POSIX_CLOCK_SELECTION)
  30 #  define _POSIX_CLOCK_SELECTION (-1)
  31 #endif
  32
  33 #if (_POSIX_CLOCK_SELECTION < 0)
  34 #   error Clock selection is not available!
  35 #endif
  36
  37 #include <vlc/vlc.h>
  38
  39 /* position at which the snapshot is taken */
  40 #define VLC_THUMBNAIL_POSITION (30./100.)
  41
  42 static void usage(const char *name, int ret)
  43 {
  44     fprintf(stderr, "Usage: %s [-s width] <video> <output.png>\n", name);
  45     exit(ret);
  46 }
  47
  48 /* extracts options from command line */
  49 static void cmdline(int argc, const char **argv, const char **in,
  50                     char **out, char **out_with_ext, int *w)
  51 {
  52     int idx = 1;
  53     size_t len;
  54
  55     if (argc != 3 && argc != 5)
  56         usage(argv[0], argc != 2 || strcmp(argv[1], "-h"));
  57
  58     *w = 0;
  59
  60     if (argc == 5) {
  61         if (strcmp(argv[1], "-s"))
  62             usage(argv[0], 1);
  63
  64         idx += 2; /* skip "-s width" */
  65         *w = atoi(argv[2]);
  66     }
  67
  68     *in  = argv[idx++];
  69     *out = strdup(argv[idx++]);
  70     if (!*out)
  71         abort();
  72
  73     len = strlen(*out);
  74     if (len >= 4 && !strcmp(*out + len - 4, ".png")) {
  75         *out_with_ext = *out;
  76         return;
  77     }
  78
  79     /* We need to add .png extension to filename,
  80      * VLC relies on it to detect output format,
  81      * and nautilus doesn't give filenames ending in .png */
  82
  83     *out_with_ext = malloc(len + sizeof ".png");
  84     if (!*out_with_ext)
  85         abort();
  86     strcpy(*out_with_ext, *out);
  87     strcat(*out_with_ext, ".png");
  88 }
  89
  90 static libvlc_instance_t *create_libvlc(void)
  91 {
  92     static const char* const args[] = {
  93         "--intf", "dummy",                  /* no interface                   */
  94         "--vout", "dummy",                  /* we don't want video (output)   */
  95         "--no-audio",                       /* we don't want audio (decoding) */
  96         "--no-video-title-show",            /* nor the filename displayed     */
  97         "--no-stats",                       /* no stats                       */
  98         "--no-sub-autodetect-file",         /* we don't want subtitles        */
  99         "--no-inhibit",                     /* we don't want interfaces       */
 100         "--no-disable-screensaver",         /* we don't want interfaces       */
 101         "--no-snapshot-preview",            /* no blending in dummy vout      */
 102 #ifndef NDEBUG
 103         "--verbose=2",                      /* full log                       */
 104 #endif
 105     };
 106
 107     return libvlc_new(sizeof args / sizeof *args, args);
 108 }
 109
 110 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
 111 static pthread_cond_t  wait;
 112 static bool done;
 113
 114 static void callback(const libvlc_event_t *ev, void *param)
 115 {
 116     float new_position;
 117     (void)param;
 118
 119     pthread_mutex_lock(&lock);
 120     switch (ev->type) {
 121     case libvlc_MediaPlayerPositionChanged:
 122         new_position = ev->u.media_player_position_changed.new_position;
 123         if (new_position < VLC_THUMBNAIL_POSITION * .9 /* 90% margin */)
 124             break;
 125     case libvlc_MediaPlayerSnapshotTaken:
 126         done = true;
 127         pthread_cond_signal(&wait);
 128         break;
 129
 130     default:
 131         assert(0);
 132     }
 133     pthread_mutex_unlock(&lock);
 134 }
 135
 136 static void event_wait(const char *error)
 137 {
 138     int ret;
 139     struct timespec ts;
 140 #define VLC_THUMBNAIL_TIMEOUT   5.0 /* 5 secs */
 141
 142     clock_gettime(CLOCK_MONOTONIC, &ts);
 143     ts.tv_sec += VLC_THUMBNAIL_TIMEOUT;
 144     pthread_mutex_lock(&lock);
 145     ret = done ? 0 : pthread_cond_timedwait(&wait, &lock, &ts);
 146     pthread_mutex_unlock(&lock);
 147
 148     assert(!ret || ret == ETIMEDOUT);
 149
 150     if (ret) {
 151         fprintf(stderr,
 152                 "%s (timeout after %.2f secs!\n", error, VLC_THUMBNAIL_TIMEOUT);
 153         exit(1);
 154     }
 155 }
 156
 157 static void set_position(libvlc_media_player_t *mp)
 158 {
 159     libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 160     assert(em);
 161
 162     libvlc_event_attach(em, libvlc_MediaPlayerPositionChanged, callback, NULL);
 163     done = false;
 164     libvlc_media_player_set_position(mp, VLC_THUMBNAIL_POSITION);
 165     event_wait("Couldn't set position");
 166     libvlc_event_detach(em, libvlc_MediaPlayerPositionChanged, callback, NULL);
 167 }
 168
 169 static void snapshot(libvlc_media_player_t *mp, int width, char *out_with_ext)
 170 {
 171     libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 172     assert(em);
 173
 174     libvlc_event_attach(em, libvlc_MediaPlayerSnapshotTaken, callback, NULL);
 175     done = false;
 176     libvlc_video_take_snapshot(mp, 0, out_with_ext, width, 0);
 177     event_wait("Snapshot has not been written");
 178     libvlc_event_detach(em, libvlc_MediaPlayerSnapshotTaken, callback, NULL);
 179 }
 180
 181 int main(int argc, const char **argv)
 182 {
 183     const char *in;
 184     char *out, *out_with_ext;
 185     int width;
 186     pthread_condattr_t attr;
 187     libvlc_instance_t *libvlc;
 188     libvlc_media_player_t *mp;
 189     libvlc_media_t *m;
 190
 191     /* mandatory to support UTF-8 filenames (provided the locale is well set)*/
 192     setlocale(LC_ALL, "");
 193
 194     cmdline(argc, argv, &in, &out, &out_with_ext, &width);
 195
 196     pthread_condattr_init(&attr);
 197     pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
 198     pthread_cond_init(&wait, &attr);
 199     pthread_condattr_destroy(&attr);
 200
 201     /* starts vlc */
 202     libvlc = create_libvlc();
 203     assert(libvlc);
 204
 205     m = libvlc_media_new_path(libvlc, in);
 206     assert(m);
 207
 208     mp = libvlc_media_player_new_from_media(m);
 209     assert(mp);
 210
 211     libvlc_media_player_play(mp);
 212
 213     /* takes snapshot */
 214     set_position(mp);
 215     snapshot(mp, width, out_with_ext);
 216
 217     libvlc_media_player_stop(mp);
 218
 219     /* clean up */
 220     if (out != out_with_ext) {
 221         rename(out_with_ext, out);
 222         free(out_with_ext);
 223     }
 224     free(out);
 225
 226     libvlc_media_player_release(mp);
 227     libvlc_media_release(m);
 228     libvlc_release(libvlc);
 229
 230     pthread_cond_destroy(&wait);
 231
 232     return 0;
 233 }