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Re: envelope error


On 15/02/2005, at 5:42 AM, bastian.schnuerle wrote:


Am 15.02.2005 um 14:12 schrieb Steve Bird:


On Feb 14, 2005, at 5:34 PM, bastian.schnuerle wrote:
When testing the unit in LogicPro 6.4.1 with longer Attack/Release Times (1-10 seconds) I can hear that the left channel is written before the right channel for the attack and the left channel stops writing before the right channel for the release. This seems logical, because the left channel is buffer[0] and right is buffer[1]. It gives me a quite nice pingpong sound,

Forgive my intrusion, but you are misunderstanding something. The fact that the left channel is buffer[0] and the right is buffer[1] has nothing to do with what you are hearing. The samples will be pulled two at a time, and sent to the hardware AT THE SAME INSTANT. In other words, at tick 0, it will output buffer[0] and buffer[1] to the two output channels. At tick 1, it will output buffer[2] and buffer[3]. And so on.
Even if what you say were true, the time difference would be one sample - not perceptible unless your sample rate is extraordinarily low.

I'm not a developer of AU's, so I can't help you further, but I wanted to clear that up.

Thank You for that information. And is this also true for an AU that overrides a New Kernel ? Because the process function for a new kernel only supports a Source Pointer and a Destination Pointer, so when using a stereo sample, (i think), it first processes the left channel and then the right channel. is this what you mean with "the time difference would be one sample" ?

No...

THe way the kernel works is that it walks through all of the input samples of each channel of the input at a time... So - you do all the left, then all the right.

You don't hear any artefacts from this, because you are processing the sound in a buffer. At some stage further down the pipe, the left/right values you altered/processed/etc will be presented to the hardware for it to "play"

If you are hearing out of sync sounds because of your processing, then that suggests to me that you are introducing this by not processing the two channels in a "similar manner" - they are played together, not one after the other.

Bill

bast
----------------------------------------------------------------
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
www.Culverson.com (toll free) 1-877-676-8175



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 >envelope error (From: "bastian.schnuerle" <email@hidden>)
 >Re: envelope error (From: "bastian.schnuerle" <email@hidden>)



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