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Re: processing question
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Re: processing question


  • Subject: Re: processing question
  • From: William Stewart <email@hidden>
  • Date: Fri, 5 Jun 2009 17:53:39 -0700


On Jun 5, 2009, at 5:17 PM, Brian Willoughby wrote:


On Jun 5, 2009, at 16:19, James Chandler Jr wrote:
Another classic illustrative example which probably resides in the same category as Normalize, would be Reverse Audio, which would rearrange a region to play backwards. Such a function isn't especially useful, but that doesn't keep it from being a fairly common feature <g>.

Thank you. That is an excellent example.

In our SDK examples we have an example and description of how to both host an offline audio unit and how to write one. The example we use as an auol unit that does reversal of audio :) (this has been available for a couple of years now)


I still think this is a useful feature (offline AU processing), but it has had limited interest from AU and host developers (unfortunately). So, to answer your comment below, I don't think the AU specification is lacking here, but more its adoption.

Thanks

Bill




If (in the host) a user does 'Select All' and then the user invokes a nonrealtime Reverse Audio function, then the Reverse Audio plugin would need free read/write random access to the entire track to get its job done.

I believe this would be impossible for AU, unless you instruct the user to click a button, play the file, click another button, and then "bounce."



In the old Premiere audio plugin scheme, which was primarily designed as a nonrealtime scheme-- A compatible host had to be smart enough to give the plugin whatever file data the plugin would request and smart enough to write whatever data the plugin would return. During processing, the plugin was boss <g>.

Also, Pro Tools first introduced the AudioSuite plugin, when non- real-time was the only thing possible. Once real time became possible on the computer (as opposed to the DSP unit), they introduced RTAS, which stands for RealTime AudioSuite. I believe that AudioSuite was more appropriate for normalize and reverse, and I think that Logic still supports AudioSuite plugins in its menus. RTAS is more appropriate for streaming, real time audio.


I may be missing something, but CoreAudio seems to be lacking anything like AudioSuite (or the Premiere system). There are a lot of powerful AU options which get close, but not close enough to handle reverse or normalize. On a side note, I had one user complain that my AUrider plugin did not produce the same results as normalize. I never could find a way to successfully convince a lay- person that normalize is completely different than a real-time automatic gain control, at least different enough that you cannot expect both to product the same file on output. Oh well...

Brian Willoughby
Sound Consulting

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References: 
 >processing question (From: Brian Davies <email@hidden>)
 >Re: processing question (From: Brian Willoughby <email@hidden>)
 >Re: processing question (From: Brian Davies <email@hidden>)
 >Re: processing question (From: Brian Willoughby <email@hidden>)
 >Re: processing question (From: James Chandler Jr <email@hidden>)
 >Re: processing question (From: Brian Willoughby <email@hidden>)

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