[theora-dev] Theora packets with granulepos of -1

Robin Siegemund r.siegemund at digitalpublishing.de
Mon Feb 16 02:17:27 PST 2009


I'm just totally confused. In my theora streams encoded using ffmpeg2theora (but also when using my own encoder) I have packets with a granulepos of -1 so I can't identify the packet during a seeking operation correctly. I can also see those strange value when I just print the packet granulepos before sending it to the Theora decoder.
I know why there are PAGES with granularpos of -1 (because no packet ends in the page) but why would PACKETS have a granularpos of -1 ?
It seems arbitrary so it's independent from keyframes.

In the Theora specs you can read:
"In this way the granulepos field increased monotonically as required by the Ogg format, but contains information necessary to efficiently find the previous keyframe to continue decoding after a seek."

This means having anything other than a monotonically increasing granulepos would break the specification.
So related to the the values I get the spec is broken, isn't it?

Or what's wrong here?

Robin Siegemund, dp

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