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 2.0.0
   6    gcc -pedantic -Wall -Werror -Wextra `pkg-config --cflags --libs libvlc` -lpthread
   7
   8   # to register the thumbnailer on gnome 3.x:
   9   cp vlc-thumb.thumbnailer /usr/share/thumbnailers
  10
  11   # to register the thumbnailer on gnome 2.x:
  12   list=`grep ^Mime vlc.desktop|cut -d= -f2-|sed -e s/";"/\\\n/g -e s,/,@,g`
  13   vid=`echo $mimes|grep ^vid`
  14   for i in $vid
  15   do
  16     key=/desktop/gnome/thumbnailers/$i/enable
  17     gconftool-2 -t boolean -s $key true
  18     gconftool-2 -t string  -s $key "vlc-thumb -s %s %u %o"
  19   done
  20  */
  21
  22 #include <assert.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <locale.h>
  28 #include <pthread.h>
  29 #include <errno.h>
  30 #include <time.h>
  31
  32 #if !defined (_POSIX_CLOCK_SELECTION)
  33 #  define _POSIX_CLOCK_SELECTION (-1)
  34 #endif
  35
  36 #if (_POSIX_CLOCK_SELECTION < 0)
  37 #   error Clock selection is not available!
  38 #endif
  39
  40 #include <vlc/vlc.h>
  41
  42 /* position at which the snapshot is taken */
  43 #define VLC_THUMBNAIL_POSITION (30./100.)
  44
  45 static void usage(const char *name, int ret)
  46 {
  47     fprintf(stderr, "Usage: %s [-s width] <video> <output.png>\n", name);
  48     exit(ret);
  49 }
  50
  51 /* extracts options from command line */
  52 static void cmdline(int argc, const char **argv, const char **in,
  53                     char **out, char **out_with_ext, int *w)
  54 {
  55     int idx = 1;
  56     size_t len;
  57
  58     if (argc != 3 && argc != 5)
  59         usage(argv[0], argc != 2 || strcmp(argv[1], "-h"));
  60
  61     *w = 0;
  62
  63     if (argc == 5) {
  64         if (strcmp(argv[1], "-s"))
  65             usage(argv[0], 1);
  66
  67         idx += 2; /* skip "-s width" */
  68         *w = atoi(argv[2]);
  69     }
  70
  71     *in  = argv[idx++];
  72     *out = strdup(argv[idx++]);
  73     if (!*out)
  74         abort();
  75
  76     len = strlen(*out);
  77     if (len >= 4 && !strcmp(*out + len - 4, ".png")) {
  78         *out_with_ext = *out;
  79         return;
  80     }
  81
  82     /* We need to add .png extension to filename,
  83      * VLC relies on it to detect output format,
  84      * and nautilus doesn't give filenames ending in .png */
  85
  86     *out_with_ext = malloc(len + sizeof ".png");
  87     if (!*out_with_ext)
  88         abort();
  89     strcpy(*out_with_ext, *out);
  90     strcat(*out_with_ext, ".png");
  91 }
  92
  93 static libvlc_instance_t *create_libvlc(void)
  94 {
  95     static const char* const args[] = {
  96         "--intf", "dummy",                  /* no interface                   */
  97         "--vout", "dummy",                  /* we don't want video (output)   */
  98         "--no-audio",                       /* we don't want audio (decoding) */
  99         "--no-video-title-show",            /* nor the filename displayed     */
 100         "--no-stats",                       /* no stats                       */
 101         "--no-sub-autodetect-file",         /* we don't want subtitles        */
 102         "--no-inhibit",                     /* we don't want interfaces       */
 103         "--no-disable-screensaver",         /* we don't want interfaces       */
 104         "--no-snapshot-preview",            /* no blending in dummy vout      */
 105 #ifndef NDEBUG
 106         "--verbose=2",                      /* full log                       */
 107 #endif
 108     };
 109
 110     return libvlc_new(sizeof args / sizeof *args, args);
 111 }
 112
 113 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
 114 static pthread_cond_t  wait;
 115 static bool done;
 116
 117 static void callback(const libvlc_event_t *ev, void *param)
 118 {
 119     float new_position;
 120     (void)param;
 121
 122     pthread_mutex_lock(&lock);
 123     switch (ev->type) {
 124     case libvlc_MediaPlayerPositionChanged:
 125         new_position = ev->u.media_player_position_changed.new_position;
 126         if (new_position < VLC_THUMBNAIL_POSITION * .9 /* 90% margin */)
 127             break;
 128     case libvlc_MediaPlayerSnapshotTaken:
 129         done = true;
 130         pthread_cond_signal(&wait);
 131         break;
 132
 133     default:
 134         assert(0);
 135     }
 136     pthread_mutex_unlock(&lock);
 137 }
 138
 139 static void event_wait(const char *error)
 140 {
 141     int ret;
 142     struct timespec ts;
 143 #define VLC_THUMBNAIL_TIMEOUT   5 /* 5 secs */
 144
 145     clock_gettime(CLOCK_MONOTONIC, &ts);
 146     ts.tv_sec += VLC_THUMBNAIL_TIMEOUT;
 147     pthread_mutex_lock(&lock);
 148     ret = done ? 0 : pthread_cond_timedwait(&wait, &lock, &ts);
 149     pthread_mutex_unlock(&lock);
 150
 151     assert(!ret || ret == ETIMEDOUT);
 152
 153     if (ret) {
 154         fprintf(stderr,
 155                 "%s (timeout after %d secs!\n", error, VLC_THUMBNAIL_TIMEOUT);
 156         exit(1);
 157     }
 158 }
 159
 160 static void set_position(libvlc_media_player_t *mp)
 161 {
 162     libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 163     assert(em);
 164
 165     libvlc_event_attach(em, libvlc_MediaPlayerPositionChanged, callback, NULL);
 166     done = false;
 167     libvlc_media_player_set_position(mp, VLC_THUMBNAIL_POSITION);
 168     event_wait("Couldn't set position");
 169     libvlc_event_detach(em, libvlc_MediaPlayerPositionChanged, callback, NULL);
 170 }
 171
 172 static void snapshot(libvlc_media_player_t *mp, int width, char *out_with_ext)
 173 {
 174     libvlc_event_manager_t *em = libvlc_media_player_event_manager(mp);
 175     assert(em);
 176
 177     libvlc_event_attach(em, libvlc_MediaPlayerSnapshotTaken, callback, NULL);
 178     done = false;
 179     libvlc_video_take_snapshot(mp, 0, out_with_ext, width, 0);
 180     event_wait("Snapshot has not been written");
 181     libvlc_event_detach(em, libvlc_MediaPlayerSnapshotTaken, callback, NULL);
 182 }
 183
 184 int main(int argc, const char **argv)
 185 {
 186     const char *in;
 187     char *out, *out_with_ext;
 188     int width;
 189     pthread_condattr_t attr;
 190     libvlc_instance_t *libvlc;
 191     libvlc_media_player_t *mp;
 192     libvlc_media_t *m;
 193
 194     /* mandatory to support UTF-8 filenames (provided the locale is well set)*/
 195     setlocale(LC_ALL, "");
 196
 197     cmdline(argc, argv, &in, &out, &out_with_ext, &width);
 198
 199     pthread_condattr_init(&attr);
 200     pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
 201     pthread_cond_init(&wait, &attr);
 202     pthread_condattr_destroy(&attr);
 203
 204     /* starts vlc */
 205     libvlc = create_libvlc();
 206     assert(libvlc);
 207
 208     m = libvlc_media_new_path(libvlc, in);
 209     assert(m);
 210
 211     mp = libvlc_media_player_new_from_media(m);
 212     assert(mp);
 213
 214     libvlc_media_player_play(mp);
 215
 216     /* takes snapshot */
 217     set_position(mp);
 218     snapshot(mp, width, out_with_ext);
 219
 220     libvlc_media_player_stop_async(mp);
 221
 222     /* clean up */
 223     if (out != out_with_ext) {
 224         rename(out_with_ext, out);
 225         free(out_with_ext);
 226     }
 227     free(out);
 228
 229     libvlc_media_player_release(mp);
 230     libvlc_media_release(m);
 231     libvlc_release(libvlc);
 232
 233     pthread_cond_destroy(&wait);
 234
 235     return 0;
 236 }