aacdec: Lower the number of frames required to detect ADTS

For live audio streams, requiring 500 frames for a stream to
be detected is a bit overkill.

This allows live ADTS streams that don't start nicely at
a frame boundary to start up more quickly, e.g.
http://mp3.streampower.be/radio1.aac.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/aacdec.c

@@ -64,7 +64,7 @@ static int adts_aac_probe(AVProbeData *p)
 
     if (first_frames >= 3)
         return AVPROBE_SCORE_EXTENSION + 1;
-    else if (max_frames > 500)
+    else if (max_frames > 100)
         return AVPROBE_SCORE_EXTENSION;
     else if (max_frames >= 3)
         return AVPROBE_SCORE_EXTENSION / 2;