[theora] Decoding Theora: Number of frames?

[Stefan Weber]

Hi all

I'm currently writing a decoder for Ogg Theora videos.
Since I'd like to show the progress of the video, I need to know how to 
read the current (with granulepos?) and total number of frames from the 
Theora header.

I didn't find an appropriate field in the header specifications for the 
total number.

Thanks for helping me out with this.

Regards,
Stefan