[FFmpeg-devel] [PATCH] improved DTS probe

[Reimar Döffinger]

This counts the different markers found and checks that it is consistent
with one specific DTS format (i.e. not markers for all dts variants
mixed) and that they are sufficiently frequent.
For the few DTS samples I tested it with it worked well and had a rather
wide margin still and probetest does not fail it...
Index: libavformat/raw.c
===================================================================
--- libavformat/raw.c   (revision 19839)
+++ libavformat/raw.c   (working copy)
@@ -491,6 +491,8 @@
 {
     const uint8_t *buf, *bufp;
     uint32_t state = -1;
+    int markers[3] = {0};
+    int sum, max;
 
     buf = p->buf;
 
@@ -500,18 +502,24 @@
 
         /* regular bitstream */
         if (state == DCA_MARKER_RAW_BE || state == DCA_MARKER_RAW_LE)
-            return AVPROBE_SCORE_MAX/2+1;
+            markers[0]++;
 
         /* 14 bits big-endian bitstream */
         if (state == DCA_MARKER_14B_BE)
             if ((bytestream_get_be16(&bufp) & 0xFFF0) == 0x07F0)
-                return AVPROBE_SCORE_MAX/2+1;
+                markers[1]++;
 
         /* 14 bits little-endian bitstream */
         if (state == DCA_MARKER_14B_LE)
             if ((bytestream_get_be16(&bufp) & 0xF0FF) == 0xF007)
-                return AVPROBE_SCORE_MAX/2+1;
+                markers[2]++;
     }
+    sum = markers[0] + markers[1] + markers[2];
+    max = markers[1] > markers[0];
+    max = markers[2] > markers[max] ? 2 : max;
+    if (markers[max] > 3 && p->buf_size / markers[max] < 32*1024 &&
+        markers[max] * 4 > sum * 3)
+        return AVPROBE_SCORE_MAX/2+1;
 
     return 0;
 }