Darren New wrote:

> It's pretty easy. There's three kinds of frames:
> 
> I - Independent. Basically JPEG. Used when going FF and Fast Reverse. 
> About every half second.
> 
> P - Predictive. Differences based on the previous I frame. About five 
> per I frame.
> 
> B - Bidirectional. Based in the previous and following frame.
> 
> Lots of cheaper mpeg encoding software doesn't do B frames, because 
> they're a PITA to calculate efficiently. Natch, with faster and faster 
> CPUs, this becomes less of a problem. 5 or 10 years ago, you could spend 
> weeks looking for an easy-to-use compressor that would do B frames.
> 
> I think the higher numbered MPEGs added more options to the encoding of 
> B frames, so that you could look at more than just one frame away, for 
> example.

I'm not really comprehending the significance of the distinction between 
P frames and B frames...

>> Damn. And here I was thinking an integer-arithmetic FFT would be 
>> really fast...
> 
> When your CPU is a 16-bit CPU on an 8-bit bus running at a dozen MHz, 
> even integer FFT is slow.

True - but the Intel product line has been 32-bit over a 32-bit bus 
since, what, the Pentium at least?

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