Calculate correct packet durations when demuxing Ogg/Speex. This involves

determining if there is any delay in the first packet and/or any truncation in
the final packet.

Originally committed as revision 20216 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/oggdec.h

@@ -50,6 +50,7 @@ struct ogg_stream {
     unsigned int pstart;
     unsigned int psize;
     unsigned int pflags;
+    unsigned int pduration;
     uint32_t serial;
     uint32_t seq;
     uint64_t granule, lastgp;