From c7806ff0cc7e52400c5b21fd97ffff6851614471 Mon Sep 17 00:00:00 2001
From: j <0x006A@0x2620.org>
Date: Wed, 28 Jul 2010 16:25:06 +0200
Subject: [PATCH] check for video

---
 src/oxframe.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/oxframe.c b/src/oxframe.c
index 8fdb702..abbd453 100644
--- a/src/oxframe.c
+++ b/src/oxframe.c
@@ -267,6 +267,7 @@ int extract_frame_ogv(oxstate *state) {
   int             fps_num = 25;
   int             fps_denom = 1;
   int             granuleshift = 6;
+  int             has_video = 0;
   long            offset;
 
   OggPlay       * player;
@@ -284,13 +285,18 @@ int extract_frame_ogv(oxstate *state) {
     if (oggplay_get_track_type (player, i) == OGGZ_CONTENT_THEORA) {
       oggplay_set_callback_num_frames (player, i, 1);
       oggplay_get_video_fps(player, i, &fps_denom, &fps_num);
+      has_video=1;
     }
     oggplay_set_track_active(player, i);
   }
+  if(!has_video) {
+    fprintf (stderr, "no video track found\n");
+    exit (1);
+  }
   oggplay_set_data_callback(player, dump_frame_callback, state);
 
   offset = 500 + 1000 * ((1 << granuleshift) - 1) * fps_denom / fps_num;
-  fprintf (stderr, "granule: %d offset %ld\n", granuleshift, offset);
+  //fprintf (stderr, "granule: %d offset %ld\n", granuleshift, offset);
 
   state->duration = oggplay_get_duration(player);