Re: Format Converter problem
Re: Format Converter problem
- Subject: Re: Format Converter problem
- From: William Stewart <email@hidden>
- Date: Mon, 28 Aug 2006 17:39:58 -0700
On 28/08/2006, at 2:26 PM, Ethan Funk wrote:
Would this be the kAudioUnitProperty_MaximumFramesPerSlice property?
Yes
Does this property apply to a HAL output unit as well
Yes - you need to make sure this is large enough to deal with the I/O
size of a particular I/O cycle
-- can I use this to set an upper limit on the HAL pulling my
entire chain?
If so, I assume setting this value to a small number would result
in the HAL output pulling on my AU chain multiple times per
render. Is this correct?
No - AUHAL won't break up pulls (the basic operations of AUs are to
pull for input based on requested output). converters like the
varispeed and time pitch will break up input pulls (because based on
their parameter settings, they can need alot more input for a given
output); in this case they restrict their pull size to max frames.
So, in AULab we set max frames up based on the I/O size for the
entire graph, as this is more efficient for memory usage and is the
most common case (where just an I/O cycle's worth of audio is being
processed at any one time).
HTH
Bill
Thanks so much. The muddy water is getting clearer now.
Ethan...
On Aug 28, 2006, at 12:18 PM, William Stewart wrote:
You have to make sure that the max frames for your AUs are set up
- by default the varispeed won't be calling for more than its max
frames setting, but if this is bigger than the AU you are
connected too, (the format converter), then you'll be asking for
it to process more sample frames than you've told it to do.
Bill
--
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