[vorbis-dev] vorbisfile close and memory callbacks

[Monty]

> 
> > ...which was absolutely necessary to alleviate pressure on the data
> > cache, not 
> > just an interface nicety.  And I'm still, a month later, dealing with 
> > occasional fallout from that change.  Double->float took two hours. 
> > Repairing 
> > two vital encode algorithms to not choke on the reduced resolution took
> 
> Was there much loss in quality due to this changeover?

No, none.  There were three reasons I used doubles to begin with:

a) Two of the LSP generation algs required double resolution; I've replaced one
algorithm (higher computational complexity, but slighly faster at our filter
sizes) and redesigend the other.

b) 'Double' is to an extent more 'native' to C than float.  Floats are often 
promoted to doubles within code (sometimes unexpectedly) and double constants 
are suffix-less.  Weak reason, sure.

c) Most processors these days handle double just as quickly (or faster) than 
float.

As it turns out, Vorbis requires a good amount of working space, and floats 
take up half the space, thus placing less pressure on the cache.

Monty

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.