fix ctts index computation when seeking, check must be done against next ctts...

fix ctts index computation when seeking, check must be done against next ctts sample, thanks to Uoti

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9007 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/mov.c

@@ -1525,12 +1525,13 @@ static int mov_seek_stream(AVStream *st, int64_t timestamp, int flags)
     if (sc->ctts_data) {
         time_sample = 0;
         for (i = 0; i < sc->ctts_count; i++) {
-            time_sample += sc->ctts_data[i].count;
-            if (time_sample >= sc->current_sample) {
+            int next = time_sample + sc->ctts_data[i].count;
+            if (next > sc->current_sample) {
                 sc->sample_to_ctime_index = i;
-                sc->sample_to_ctime_sample = time_sample - sc->current_sample;
+                sc->sample_to_ctime_sample = sc->current_sample - time_sample;
                 break;
             }
+            time_sample = next;
         }
     }
     return sample;