[vorbis-dev] vorbis on playstation 2

Segher Boessenkool segher at koffie.nl
Thu Feb 6 18:12:04 PST 2003

Michael Smith wrote:
>>There shouldn't be any double precision floats -- please report these
>>as a bug (bugs.xiph.org).  Except maybe in lsp/lpc stuff (but that's
>>ancient, and not used in 1.0 files anymore; your application doesn't
>>need to support floor0 at all, probably).
> Note that there _are_ some doubles in libvorbisfile. They're mostly there to 
> avoid breaking API compatibility. They're not in speed-critical parts of the 
> code, though. 

Ah yes, as always, I'm not thinking about libvorbisfile at
all.  Sorry about that.

> On a controlled system (i.e. where you don't care about breaking binary 
> compatiblity), it's completely safe to change all these to floats.
> I think there are also some (only a few) doubles on encode-side which are 
> required. However, you obviously don't need to worry about that for a 
> decoder. Those might only be in the LSP/LPC code, though, I'm not sure.

The only doubles required in the encoder were in the floor0
code, indeed.  And that has all been removed IIRC.

Maybe the psy code needs some doubles right now; it should be
fixed, if so.

> I suspect the main problem is accidental double-precision constants. Most of 
> these got fixed, but they have a tendency to creep back in...

Yeah, I know.  I grep the asm output for double precision
fp insns to find out :)

I'll try and see what's the current state of things.


<p>--- >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.

More information about the Vorbis-dev mailing list