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Subject: Re: OggVorbis for CPUs without FPU
From: Vladimir Pantelic (pan_at_nt.tu-darmstadt.de)
Date: 2002-09-04


Linus G Larsson wrote:
> Hi all,
>
> I don't want to ask the same question "can we support vorbis" again,
> just tell people who might not know it that Xiph has released Tremor, a
> Vorbis decoder for CPUs that don't have an FPU, under a BSD-like
> license:
> http://www.xiph.org/ogg/vorbis/hardware.html
>
> Anyway, how is the progress going with the exploring of the MAS? Is it
> just na´ve to hope for rockbox to be able to download a new codec into
> the DSP?

A little look into the Tremor sources reveals:

$ grep static window.c
static ogg_int32_t vwin64[32]={
static ogg_int32_t vwin128[64]={
static ogg_int32_t vwin256[128]={
static ogg_int32_t vwin512[256]={
static ogg_int32_t vwin1024[512]={
static ogg_int32_t vwin2048[1024]={ = 4k
static ogg_int32_t vwin4096[2048]={ = 8k
static ogg_int32_t vwin8192[4096]={ = 16k

$ grep static mdct_lookup.h
static ogg_int32_t triglook_64[80]={
static ogg_int16_t bitrevlook_64[16]={
static ogg_int32_t triglook_128[160]={
static ogg_int16_t bitrevlook_128[32]={
static ogg_int32_t triglook_256[320]={
static ogg_int16_t bitrevlook_256[64]={
static ogg_int32_t triglook_512[640]={
static ogg_int16_t bitrevlook_512[128]={
static ogg_int32_t triglook_1024[1280]={
static ogg_int16_t bitrevlook_1024[256]={
static ogg_int32_t triglook_2048[2560]={ = 10k
static ogg_int16_t bitrevlook_2048[512]={ = 1k
static ogg_int32_t triglook_4096[5120]={ = 20k
static ogg_int16_t bitrevlook_4096[1024]={ = 2k
static ogg_int32_t triglook_8192[10240]={ = 40k!!
static ogg_int16_t bitrevlook_8192[2048]={ = 4k

This makes roughly > 100k needed for the tables only!
I doubt that this will fit even in the ROM of the MAS DSP,
not to talk about the RAM that is left for customer code....

Regards,

Vladimir



Page was last modified "Jan 10 2012" The Rockbox Crew
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