[openal] "Performance" Question

developer at oldunreal.com developer at oldunreal.com
Sat May 31 01:39:14 EDT 2014

Thanks, that doesn't allow me a direct comparison, but these values are 
very revealing.
And yes, it should be compatible, but for some yet unknown reason I get 
reports that it doesn't seem to in every case.

On 22.05.2014 02:52, Daniel Gibson wrote:
> Am 22.05.2014 02:47, schrieb Chris Robinson:
>> On 05/18/2014 10:51 PM, developer at oldunreal.com wrote:
>>> I am using OpenALSoft for quite a while already in Linux for my project
>>> and decided to move on from Creatives OpenAL Version to OpenALSoft in
>>> Windows too. I avoided it so far because it seemed to run flawlessly 
>>> and
>>> it was able to initialize the (Creative) Hardware directly. Now that I
>>> switched people are afraid of losing hardware acceleration. I know
>>> OpenALSoft initializes DSound and WinMM but I have honestly no idea
>>> about how much these are can benefit from any hardware acceleration
>>> provided by a soundcard.
>>> Are there any charts, further information, comparisons or whatever to
>>> compare that? Is there even a difference in the end? I was not able to
>>> find a measurable quantity so far, but to appease the people I'd 
>>> love to
>>> know more about that topic if possible.
>> I don't have any comparisons, but as a quick test I did, the current git
>> head of OpenAL Soft is able to process 512/1024 sample updates from a
>> couple dozen sources, and one reverb effect, in about 0.5 ~ 1ms (64-bit
>> Linux, AMD Athlon64 X2 4200+ which is a fairly old dual-core CPU). This
>> is with each of those sources having their properties updated 30+ times
>> a second, using cubic resampling (the default is linear, which is
>> faster). It'd be a bit worse with HRTF enabled, but more than good
>> enough for general use.
>> The biggest benefit you'll have with a hardware OpenAL driver is audio
>> quality. Hardware can employ better techniques for resampling, filters,
>> and effects since it won't bog down the CPU at all. It would also
>> potentially have the benefit of more types of filters and effects,
>> although OpenAL Soft is slowly but surely adding more of them (high-pass
>> and band-pass filters were implemented very recently).
> I guess that using lots of EFX effects could have a noticable 
> performance impact compared to hardware acceleration - but in the end 
> one just needs to test whether it's an unacceptable slowdown in the 
> specific application or not.
> Shouldn't OpenAL-softs and Createives openal.dll be compatible anyway, 
> so people could just use whatever they want, even if you develop 
> against OpenAL soft (assuming you don't rely on extensions unsupported 
> by Creative)?
> Cheers,
> Daniel
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