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Re: Convert to float and more
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Re: Convert to float and more


  • Subject: Re: Convert to float and more
  • From: BlazeAudio Developer <email@hidden>
  • Date: Tue, 10 Jun 2003 11:55:01 -0700

Perhaps I have older code, but I found the following in the
PhantomAudioDriver:

NativeInt32ToFloat32(&(((long *)sampleBuf)[firstSampleFrame]), &(((float
*)sampleBuf)[firstSampleFrame]), numSampleFrames *
streamFormat->fNumChannels, 32);

Shouldn't the indices be firmSampleFrame * streamFormat->fNumChannels?

I'm using the April 03 SDK.

Thanks.
Devendra.


At 11:05 PM 6/4/2003, Matt Gonzalez wrote:

Check out the most recent PhantomAudioDriver; it has optimized
Altivec routines for doing this. Very thoughtful of Apple - I was
able to just drop them into my driver.

Matt

BlazeAudio Developer wrote:

A

Instead, you should use the blitters in the AudioConverter.

how fast is the AudioConverter compared to sample/32768?

The AudioConverter blitters use Altivec, are fully optimized,
and
take advantage of a few neat math tricks so they're a ton
faster.

Jeff,

Where can I get more details on these optimizations. I'm thinking
about
putting them to use in CoreAudio drivers (clipOutputSamples() and
convertInputSamples()).

Thanks.
Devendra.
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References: 
 >Re: Convert to float and more (From: "Mark's Studio" <email@hidden>)
 >Re: Convert to float and more (From: BlazeAudio Developer <email@hidden>)
 >Re: Convert to float and more (From: Matt Gonzalez <email@hidden>)

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