audio input level

[Luc Vanturenhout]

ce 24/Nov/2004Mer 07:24, Dan Soneson <sonesond1 at southernct.edu> a écrit dans "audio input 
level" :
 
> I am trying to set the audio input level (called input volume in the 
> Sound pane of the system preferences in Mac OS X 10.3) from within 
> Revolution. Anyone have any experience doing this or any suggestions as 
> to how to go about doing this?
> 
> More information: I am working on an app to do voice recording, but 
> sometimes the system setting for the input volume is very low. I would 
> like to avoid the step of going out of the app to open the system 
> preferences and set the input level manually.
> 
> Ideally, I would like to set the input level on both Mac and Window 
> machines. Any suggestions would be appreciated.
> 
> Thanks,
> Dan Soneson

Hi ,

The only way to do this correctly (in a WAV/AIFF/SDII native format)
in Mac OS X , is to use directly the API of the AudioCore Engine who
manage the sound in the OS : shellscript or applescript with call/return
through a Rev's script at the stack stage (background perhaps !) ,
or - finest - in a "pre-OpenStack-Script" !
More infos in the Tech-doc from Apple at :
<http://developer.apple.com/audio/>

I suppose that's it also possible in Windows or Linux , isn't it ! ;o)

By this way , you have access at all the possibilities : level(s) ,
normalization , equalisation through plug-in's , .... more and more  ! :o))
(with 16 or 24 bit format and at 22 KHz --> 96 KHz in quantification freq.
 if your soundCard offer the choise)
Be carefull : take a special look at the mamagement of the created file ,
... with this native format , sound file are BIG !
(16 bit at 48 KHz is 10 Mo/minute !!!)
You can do this with storage in temporary file , treatments on this file ,
and finally transform the file - if you want it ! - into a more appropriate
format (mp3 , ...) before return of the final file in Rev .
You can "read on the fly" the returned file in a player in Rev (AIFF,WAV or mp3).
 [with "modern" machine (processor at more than 1GHz) the "time" of
  treatments are correct (< 10 ms) IF all scripts and process are
  good optimized and NOT "too mutch" sophisticated]

If you are working with "compressed" sound format (like mp3 ... and so on ) ,
a call to the QuickTime volume command into a Rev player is also possible .
(But , i think , without the possibility of displaying the command in the GUI) 
See mervellous "EnhancedQT_External Xternal" at :
<http://www.mangomultimedia.com/developer/revolution/>
and take a look at the "enhancedqt_api" .

(Sorry for my poor english  ;o/ )

Regards

Luc
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