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Old 11 March 2005, 09:35 pm   #1
eye
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Join Date: Mar 2005
Location: München, Germany
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Default Slow ARM feasible?

Hello.

I am programming stuff for Dreamcast at the moment. As a sound co-processor it has a DSP with a built-in ARM7 chip, running, according to the specifications lying out in the net, at 45 MHz. This whole thing is attached to 2 MB RAM. Among technical challenges is the slowness of the system, and the lack of an FPU.

I recall i have seen a codec based on libtremor which decodes 96kpbs oggvorbis files usually without getting into performance trouble, running solely on this ARM7 coprocessor - however, i cannot find it again and having asked for it in another forum i was pointed to Musepack. I looked through the libmusepack archive but it lacked the documentation to answer my questions so i hope someone out here can answer them.

- How much space does libmusepack decoder need?
- How would you think would Musepack compare in performace to libtremor, on such a target? I have seen a comparison to normal libvorbis, but it doesn't say me much since libtremor should be faster by orders of magnitude even on a real machine, and floating-point emulation is simply deadly.
- How hard should it be to adapt it to the target?
- Can it easily be made read from a circular input buffer?

Additionally, would anyone like to assist me? Perhaps someone who owns a Dreamcast and perhaps was intending to do something along the lines anyway? I am still quite unfamiliar with the hardware, and i have to get the prod out within 2 weeks, for the Breakpoint party (see breakpoint.untergrund.net). I'm pretty much in trouble because my time is getting very tight.

Regards, eye/photoAllergics.
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