[vorbis] Vorbis on Palm OS

Michael Smith msmith at labyrinth.net.au
Fri Apr 5 15:48:51 PST 2002



At 10:41 AM 4/5/02 -0800, you wrote:
>Hi there.  Apologies if this is off-topic -- I'll be happy to take this
>offline with the right individual(s).
>
>For those who don't know, the next generation Palm Powered devices will
>feature ARM processors and a new digital sound playback API, so naturally
>I'm working on a software Vorbis decoder app.
>
>Given the (probable) lack of floating point hardware on these devices, I'm
>interested in knowing how well the reference decoder is optimized for
>integer math.  I'm not having any trouble porting the codec to PalmOS/ARM,
>but I'm happy to admit that my math skills are nowhere near sufficient to
>understand its inner workings.
>
>My guess is that if floating point math is used extensively, and if I have
>to emulate it all in software, there might not be enough horsepower for
>real-time decoding.

You're right - libvorbis is not highly optimised, and it simply won't
decode in real time without hardware floating point support.

There are integer decoders available for sale/licensing, as an altenative -
optimised for ARM processors (xiph.org needs to make money somehow, or
the programmers don't survive... sorry).

The alternative is to develop a integer decoder yourself (or to integerise
more of libvorbis - a few bits have integer implementations), which is
certainly possible, but not easy.

(yes, vorbis-dev is generally more appropriate for this sort of thing,
but it's not critical. Just don't crosspost to both)

Michael

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