• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: kStereoMixerParam_PreAveragePower
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: kStereoMixerParam_PreAveragePower


  • Subject: Re: kStereoMixerParam_PreAveragePower
  • From: Chris Rogers <email@hidden>
  • Date: Mon, 1 Nov 2004 15:29:49 -0800

Title: Re: kStereoMixerParam_PreAveragePower
Mark,

Sorry this is a bit confusing and isn't really documented in AudioUnitParameters.h

Set the scope to either kAudioUnitScope_Input or kAudioUnitScope_Output
(in the input case the element argument determines which input bus -
for the output case element must equal 0 since there's only one output bus)

The parameter ID value to use is the one defined in AudioUnitParameters.h
(kStereoMixerParam_PreAveragePower/kStereoMixerParam_PostAveragePower, etc.)
*plus* the channel number, thus:

kStereoMixerParam_PreAveragePower + 0      // left channel
kStereoMixerParam_PreAveragePower + 1      // right channel

Hope this helps...

Chris Rogers
Core Audio
Apple Computer




Hi Folks,

I'm experimenting with the StereoMixer AU.  I have the stereo mixer
connected to a kAudioUnitSubType_DefaultOutput outputAU.  I can change
volume and pan without any problem.  However, I have some questions:

1) How do I read Left and Right values for the
kStereoMixerParam_PreAveragePower/kStereoMixerParam_PostAveragePower
parameters?  When I pass anything other than 0 as the element parameter to
AudioUnitGetParameter, I get back an kAudioUnitErr_InvalidElement error.
The value I get back for element 0 appears to be for the left channel only.

2) How frequently should I be sampling the kStereoMixerParam_PreAveragePower
paramter.  The MatrixMixerTest sample schedules its timer at 0.02s
intervals.  When I use this interval, I find that the Average power levels
I'm getting appear to be out of sync with the music.

Thanks.  I'm sorry if these are RTFM questions, but all my searches came up
empty.

Cheers
-Mark

---------------------------------------------------------------------
Mark Alldritt                         Late Night Software Ltd.
Phone: 250-380-1725                   333 Moss Street
FAX:   250-383-3204                   Victoria, B.C.
WEB:   http://www.latenightsw.com/    CANADA  V8V-4M9

 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
>com

This email sent to email@hidden

 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:

This email sent to email@hidden

References: 
 >kStereoMixerParam_PreAveragePower (From: Mark Alldritt <email@hidden>)

  • Prev by Date: Re: Bug in AUEventListener?
  • Next by Date: Re: Looking for tutorial
  • Previous by thread: kStereoMixerParam_PreAveragePower
  • Next by thread: Re: Looking for tutorial
  • Index(es):
    • Date
    • Thread