typefind: bump probability if all frames we found are similar

Similar meaning same layer, same bitrate, and same number of channels

This fixes misdetection of (some MP3 files that have zero padding
between the ID3 tag and the MP3 stream) as H.264 video.

https://bugzilla.gnome.org/show_bug.cgi?id=656018

diff --git a/gst/typefind/gsttypefindfunctions.c b/gst/typefind/gsttypefindfunctions.c
index 4b6f805..5d3d95c 100644 (file)
--- a/gst/typefind/gsttypefindfunctions.c
+++ b/gst/typefind/gsttypefindfunctions.c
@@ -1014,6 +1014,7 @@ mp3_type_find_at_offset (GstTypeFind * tf, guint64 start_off,
       guint layer = 0, bitrate, samplerate, channels;
       guint found = 0;          /* number of valid headers found */
       guint64 offset = skipped;
+      gboolean changed = FALSE;
 
       while (found < GST_MP3_TYPEFIND_TRY_HEADERS) {
         guint32 head;
@@ -1064,6 +1065,8 @@ mp3_type_find_at_offset (GstTypeFind * tf, guint64 start_off,
            * that this is not a mp3 but just a random bytestream. It could
            * be a freaking funky encoded mp3 though. We'll just not count
            * this header*/
+          if (prev_layer)
+            changed = TRUE;
           prev_layer = layer;
           prev_channels = channels;
           prev_samplerate = samplerate;
@@ -1094,6 +1097,8 @@ mp3_type_find_at_offset (GstTypeFind * tf, guint64 start_off,
           probability = GST_TYPE_FIND_MINIMUM;
         if (start_off > 0)
           probability /= 2;
+        if (!changed)
+          probability = (probability + GST_TYPE_FIND_MAXIMUM) / 2;
 
         GST_INFO
             ("audio/mpeg calculated %u  =  %u  *  %u / %u  *  (%u - %"