[vorbis-dev] mdct.c

[Pattara Kiatisevi]

Hi,

Thank you for all answers.

On Thu, 14 Mar 2002, Monty wrote:

>
>
>
> On Fri, Mar 15, 2002 at 12:33:49AM +0100, Segher Boessenkool wrote:
> > > Vorbis has a lower limit on blocksize of 64, so the code is not intended
> > > to work on anything smaller.
> >
> > It's the other way around, actually.  libvorbis doesn't support blocksizes
> > smaller than 64 (or is it 128?), and so the spec was changed.
>
> Not true.  <64 is just not that useful.  The code took advantage of
> it.  The upper limit, by spec at the moment, is 8192 BTW.
                           ^^^^
                Hmm, this spec (of Ogg/Vorbis?) is published somewhere?

As we're trying to put libvorbis on LEON chip running on XSV-800 FPGA
board, the code runs now (simple player using Pthread on RTEMS/LEON)  but
it seems that we have to implement some functions in hardware in order to
help speed up the decoding process. We target this mdct_backward()
first. Do you have any comment? Is there any other hardware-friendly and
computation-intensive functions?

I am looking at the code from http://sourceforge.net/projects/ivdev/
provided by Mr.Dan Conti and trying to make it "compilable" with gcc on
Linux (if I have duplicating anyone's work please let me know :) ). As we
have the limit that our FPU can run at only 25 MHz (which might not be
fast enough to decode Ogg/Vorbis), we prefer to go with the no-fpu version
so that we could run with higher frequency.

More information about the project: http://oggonachip.sourceforge.net/

Any comments are very appreciated,
Pattara

<p><p><p>>
> Monty
>
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