[xiph-commits] r17775 - trunk/ffmpeg2theora/src

[j at svn.xiph.org]

Author: j
Date: 2011-01-09 21:04:13 -0800 (Sun, 09 Jan 2011)
New Revision: 17775

Modified:
   trunk/ffmpeg2theora/src/theorautils.c
   trunk/ffmpeg2theora/src/theorautils.h
Log:
patch by Chris P. to correct Vorbis granulepos in OggIndex in case a packet has more samples than its granulepos reports.

Modified: trunk/ffmpeg2theora/src/theorautils.c
===================================================================
--- trunk/ffmpeg2theora/src/theorautils.c	2011-01-09 21:39:54 UTC (rev 17774)
+++ trunk/ffmpeg2theora/src/theorautils.c	2011-01-10 05:04:13 UTC (rev 17775)
@@ -854,6 +854,7 @@
         vorbis_block_init (&info->vd, &info->vb);
         
         seek_index_init(&info->vorbis_index, info->index_interval);
+        info->vorbis_granulepos = 0;
     }
     /* audio init done */
 
@@ -1275,6 +1276,31 @@
             info->prev_vorbis_window = info->vb.pcmend;
 
             ogg_int64_t start_granule = op.granulepos - num_samples;
+            if (start_granule < 0) {
+                /* The first vorbis content packet can have more samples than
+                   its granulepos reports. This is allowed by the spec, and
+                   players should discard the leading samples and not play them.
+                   Thus the indexer needs to discard them as well.*/
+                if (op.packetno != 4) {
+                    /* We only expect negative start granule in the first content
+                       packet, not any of the others... */
+                    fprintf(stderr, "WARNING: vorbis packet %d has calculated start"
+                            " granule of %lld, but it should be non-negative!",
+                            op.packetno, start_granule);
+                }
+                start_granule = 0;
+            }
+            if (start_granule < info->vorbis_granulepos) {
+                /* This packet starts before the end of the previous packet. This is
+                   allowed by the specification in the last packet only, and the
+                   trailing samples should be discarded and not played/indexed. */
+                if (!op.e_o_s) {
+                    fprintf(stderr, "WARNING: vorbis packet %d (granulepos %lld) starts before"
+                            " the end of the preceeding packet!", op.packetno, op.granulepos);
+                }
+                start_granule = info->vorbis_granulepos;
+            }
+            info->vorbis_granulepos = op.granulepos;
             ogg_int64_t start_time = vorbis_time (&info->vd, start_granule);
             
             if (op.granulepos != -1 &&

Modified: trunk/ffmpeg2theora/src/theorautils.h
===================================================================
--- trunk/ffmpeg2theora/src/theorautils.h	2011-01-09 21:39:54 UTC (rev 17774)
+++ trunk/ffmpeg2theora/src/theorautils.h	2011-01-10 05:04:13 UTC (rev 17775)
@@ -157,6 +157,8 @@
                                calculate duration of vorbis packets. */
     /* The offset of the first non header page in bytes. */
     ogg_int64_t content_offset;
+    /* Granulepos of the last encoded packet. */
+    ogg_int64_t vorbis_granulepos;
 
     ogg_int32_t serialno;
 }