variable frame rate for Theora

Hi there,

I have just read in the documentation that Theora doesn't support 
variable frame rates. I don't know whether it will support it in the 
near future and since I cannot code I don't really know whether this 
would be easy to implement. But I'd ask you to consider implementing 
variable frame rates.

The reason for that implementation would come from the much smaller size 
  in screencasts and presentations.

Screencasts can benefit if the frames are recorded only when something 
in the screen or selected area changes (this would be even more useful 
if mouse pointer isn't recorded).

And for presentations, I have the following example: 
http://lessig.blip.tv/. Setting  a constant frame rate to one frame per 
second (which would give wrong audio sync) the total number of frames 
would be higher with that constant frame rate than with a variable frame 
rate that only records frames when slides change.

Because of these, I think that considering the implementation of 
variable frame rates would be extremely useful for screencasts and 
sharing presentations on the net.

Could you please consider this implementation.

Many thanks for the excellent work on theora,


Pablo