[vorbis-dev] Suggestion for libvorbisfile: scaling

[Herman Oosthuysen]

For embedded use, you should perhaps look at MAD, a fixed point
implementation of MP3.  Otherwise, you'll have to rewrite the whole ogg
thing in fixed point code, which will be a monstrous job - like MAD...

Cheers,

--
Herman Oosthuysen
Herman at WirelessNetworksInc.com
Suite 300, #3016, 5th Ave NE,
Calgary, Alberta, T2A 6K4, Canada
Phone: (403) 569-5688, Fax: (403) 235-3965
----- Original Message -----
From: Ian Walters <ianw at trolltech.com>
To: <vorbis-dev at xiph.org>; Jack Moffitt <jack at xiph.org>
Sent: Friday, January 04, 2002 6:49 AM
Subject: Re: [vorbis-dev] Suggestion for libvorbisfile: scaling

<p>> On Thu, 3 Jan 2002 7:32 pm, Jack Moffitt wrote:
> > > My suspicion is that floats are not used internally by ov_read(), and
> > > there would be a speed penalty for using ov_read_float().
> >
> > Vorbis is natively float based.  ov_read_float will be quite a bit
> > faster than ov_read, since it won't have the huge float->int conversion,
> > etc (note that on x86, the float->int conversion is in assembler so it's
> > pretty fast).
>
> Which is a pity from the embedded perspective.  I had a look at porting
> Vorbis to the arm recently  and had no luck getting fast yet listenable
> playback.  I was only using float emulation stuff, not trying to remove
> floats from vorbis.  Unfortunately I won't be able to come back to this
for a
> long time, but I was wondering how much the design of vorbis depends on
> floats.  It would be nice to have a audio format like vorbis in the pda
arena.
>
> >
> > ov_read() 's conversion is still one of the slower functions on decode,
> > especially on PPC it seems.
> >
> > jack.
> >
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<p>--- >8 ----
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