Re: usage of AUTimePitch in an AUGraph
Re: usage of AUTimePitch in an AUGraph
- Subject: Re: usage of AUTimePitch in an AUGraph
- From: Doug Wyatt <email@hidden>
- Date: Mon, 29 Aug 2005 12:59:19 -0700
On Aug 27, 2005, at 14:38, thomas rettich wrote:
I've used the aufileplayer au to play the file and connected it the
default output which worked fine. but when I try to add a node for
autimepiotch in the graph (bewteen the fileplayer and the ouput
units) it wouldn't work (i.e. aufileplayer -> autimepitch ->
outputunit). can anybody help ?? do I have to set a different
format for the input bus of the output unit since autimepitch
converts the format.. if so what exactly do I have to do ?
That should work. That's the same chain you get in AULab when you
connect a file player to a time/pitch (minus the mixers).
So you have a file player going to an output unit and that works, and
when you add the time/pitch it stops working? When you say it
"wouldn't work" -- exactly what happens when?
Make sure that you've got a canonical deinterleaved float32 format
through the chain and that the sample rates are consistent
(especially that none are zero).
Exactly how are you specifying the start time to the file player?
one more thing I was trying to figure out ... if an audio unit is
using a callback to obtain audio data and in the callback function
the data is retrieved from an audio file, which buffer do i have to
write the data into, where do I have to allocate the memory for the
buffer and what size should it be ?
An AU's input callback proc is responsible for copying samples into
the supplied AudioBufferList. The samples must in the format of the
AU's input element (usually deinterleaved float32).
Presumably at some earlier point you have read samples from a file
and converted them to float. If you want to do this yourself without
an AUAudioFilePlayer then you'll need to create a separate read
thread and some reasonably large disk I/O buffers.
--
Doug Wyatt
Core Audio, Apple
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