Re: Processing stereo data?
Re: Processing stereo data?
- Subject: Re: Processing stereo data?
- From: Rick Mann <email@hidden>
- Date: Tue, 08 Mar 2011 23:57:18 -0800
Thanks, Joe, that's very helpful. Not only do I have to process both channels together simultaneously, I also need to use the last few samples, to generate the next one, and I'm not sure how to do that across invocations (other than just storing the last samples from the previous invocation. Oh, and I need to produce mono output, but that will hopefully be more straightforward.
Thanks for showing me ProcessBufferLists(). That'll help.
--
Rick
On Mar 8, 2011, at 23:51:05, Joe Völker wrote:
> In the current AudioCore version, Process() will only handle one channel. They're just pointing out that IF a future version MIGHT support more than one channel, the inNumChannels would be the way to go.
>
> The AUKernel is created for every channel, each with its own Process() instance. This works fine in a number of multichannel scenarios: Your "mono" Process() will yield a Plug-In that will handle ANY number of channels, from 1 to infinity. That is cool for a gain changer or a filter.
>
> On the other hand, if you NEED info on channel B while processing channel A, you're lost. You'll dump AUKernel and subclass ProcessBufferLists() instead, and this is where the real fun starts.
>
> Core Audio's Documentation is flaky, to say the least. Working though the examples is the way to go. I gained a lot of insight from reading the AUEffectsBase and AUBase class files which are heavily commented.
>
> Regards,
>
> Joe
>
>
> Am 09.03.2011 um 05:12 schrieb Rick Mann:
>
>> I'm working through the Audio Unit Programming Guide Simple Effect tutorial. I've created an Audio Unit Effect from Xcode 2.3.5 stationery.
>>
>> The comments in the Process() method say that num channels is always 1, and that it requires non-interleaved format for all inputs and outputs.
>>
>> But then when they advance the input sample pointer by inNumChannels (which is 1), the comment says "stereo, we're advancing 2 samples".
>>
>> In any case, my effect only gets one channel. How can I work with stereo data? Is that covered later in the tutorial?
>>
>> TIA,
>> Rick
>>
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