[Vorbis-dev] Performance on low-CPU devices

[Martin Vilcans]

Thanks for your replies. I'll dig into Tremor. I've also found OggPlay, 
which is a Symbian application. I guess I can get performance 
measurements out of that one.

Martin

Michael Smith wrote:
> On Wed, 12 Jan 2005 15:26:40 +0100, Martin Vilcans <martin at jadestone.se> wrote:
> 
>>Hi!
>>
>>I'm new to this list. I work at a game development company, and we are
>>considering Ogg Vorbis for the audio in a cell phone game. Does anyone
>>here have any figures or educated guesses on how much CPU power the
>>decoding requires? I guess Tremor is the decoder to use, as the CPU
>>doesn't have a floating point unit, but will it be possible to use it
>>for playing background music in a cell phone game?
> 
> 
> Yeah, Tremor would be the one to use. You can certainly decode on
> (modern) cell phones, but whether it's appropriate really depends on
> how much cpu you can afford to use on the music. Tremor also has a
> low-mem version, which is designed to work in extremely memory
> constrained environments, but that uses a little more cpu - a cell
> phone probably has enough memory that you're better off using the
> faster version, but maybe that's something to experiment with.
> 
> There's a Tremor mailing list too - if you end up deciding to use it,
> and you want help with getting it up and running, that's probably a
> better place to ask.
> 
> 
>>The target platform has an ARM at around 100 MHz. Any ideas about how
>>much of the CPU would be used for decoding? Is it faster to decode lower
>>bitrates and/or lower sample frequencies?
> 
> 
> For CD rate audio (stereo, 44.1kHz), you'll use a lot of that cpu.
> Maybe up around 40-60% (I really don't know precisely). However, it's
> likely that you don't really need cd-quality audio, and using fewer
> channels (i.e. mono), and lower sample frequencies will dramatically
> reduce the cpu load. Lower bitrates also help, but to a much smaller
> degree.
> 
> It's really hard to say whether this is ok for your uses - it depends
> on what sort of audio quality you're aiming for, and how much of your
> CPU you're willing to use up on music, and of course on the precise
> details of the device. You're best off experimenting, and then asking
> more specific questions down the track.
> 
> Mike