change sample aspect ratio test to be more clear, print old one

Originally committed as revision 16703 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mov.c

@@ -439,10 +439,11 @@ static int mov_read_pasp(MOVContext *c, ByteIOContext *pb, MOVAtom atom)
     const int den = get_be32(pb);
     AVStream * const st = c->fc->streams[c->fc->nb_streams-1];
     if (den != 0) {
-        if ((st->sample_aspect_ratio.den && den != st->sample_aspect_ratio.den) ||
-            (st->sample_aspect_ratio.num && num != st->sample_aspect_ratio.num))
+        if ((st->sample_aspect_ratio.den != 1 || st->sample_aspect_ratio.num) && // default
+            (den != st->sample_aspect_ratio.den || num != st->sample_aspect_ratio.num))
             av_log(c->fc, AV_LOG_WARNING,
-                   "sample aspect ratio already set, overriding by 'pasp' atom\n");
+                   "sample aspect ratio already set to %d:%d, overriding by 'pasp' atom\n",
+                   st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
         st->sample_aspect_ratio.num = num;
         st->sample_aspect_ratio.den = den;
     }