[ogg-dev] [PATCH] liboggz: Update Dirac granulepos definition

[David Flynn]

The definition of granule position for an OggDirac elementary stream
isn't the same as theora.

Index: tools/oggz_tools.c
===================================================================
--- tools/oggz_tools.c	(revision 3759)
+++ tools/oggz_tools.c	(working copy)
@@ -454,7 +454,15 @@
     iframe = granulepos >> granuleshift;
     pframe = granulepos - (iframe << granuleshift);
 
-    ret = fprintf (stream, "%" PRId64 "|%" PRId64, iframe, pframe);
+    if (oggz_stream_get_content (oggz, serialno) != OGGZ_CONTENT_DIRAC) {
+      ret = fprintf (stream, "%" PRId64 "|%" PRId64, iframe, pframe);
+    } else {
+      uint32_t pt = (iframe + pframe) >> 9;
+      uint16_t dist = ((iframe & 0xff) << 8) | (pframe & 0xff);
+      uint16_t delay = pframe >> 9;
+      int64_t dt = pt - delay;
+      ret = fprintf (stream, "(pt:%u,dt:%"PRId64",dist:%hu,delay:%hu)", pt, dt, dist, delay);
+    }
   }
 
   return ret;
Index: liboggz/oggz_auto.c
===================================================================
--- liboggz/oggz_auto.c	(revision 3759)
+++ liboggz/oggz_auto.c	(working copy)
@@ -358,31 +358,26 @@
 static int
 auto_dirac (OGGZ * oggz, long serialno, unsigned char * data, long length, void * user_data)
 {
-  char keyframe_granule_shift = 32;
-  int keyframe_shift;
+  int granule_shift = 22; /* not a typo */
   dirac_info *info;
 
   info = malloc(sizeof(dirac_info));
 
   dirac_parse_info(info, data, length);
 
-  /*
-  FIXME: where is this in Ogg Dirac?
-  keyframe_granule_shift = (char) ((header[40] & 0x03) << 3);
-  keyframe_granule_shift |= (header[41] & 0xe0) >> 5; 
-  */
-  keyframe_shift = keyframe_granule_shift;
-
 #ifdef DEBUG
-  printf ("Got dirac fps %d/%d, keyframe_shift %d\n",
-	  fps_numerator, fps_denominator, keyframe_shift);
+  printf ("Got dirac fps %d/%d, granule_shift %d\n",
+          info->fps_numerator, info->fps_denominator, granule_shift);
 #endif
 
-  oggz_set_granulerate (oggz, serialno, (ogg_int64_t)info->fps_numerator,
+  /* the granulerate is twice the frame rate (in order to handle interlace)
+   * it is also multiplied by (1<<9) since the decode time is stored in
+   * the top 32bits of granulepos, but the granule_shift is 22. */
+  oggz_set_granulerate (oggz, serialno, 2*(1<<9)*(ogg_int64_t)info->fps_numerator,
                         OGGZ_AUTO_MULT * (ogg_int64_t)info->fps_denominator);
-  oggz_set_granuleshift (oggz, serialno, keyframe_shift);
+  oggz_set_granuleshift (oggz, serialno, granule_shift);
 
-  oggz_stream_set_numheaders (oggz, serialno, 3);
+  oggz_stream_set_numheaders (oggz, serialno, 0);
 
   free(info);
   return 1;