Re: Sample Rate Conversion using AudioConverter
Re: Sample Rate Conversion using AudioConverter
- Subject: Re: Sample Rate Conversion using AudioConverter
- From: Bill Stewart <email@hidden>
- Date: Fri, 6 Jun 2003 18:49:39 -0700
Ummm... sample rate conversion on imaginary sample values...
No - just because we'd run out of names (and the AudioBufferList is
more complex than a void* blob of memory) - you should all be really
thankful, we almost had to introduce
AudioConverterFillReallyComplexBuffer :-) but we didn't:)
Bill
On Friday, June 6, 2003, at 12:27 PM, Tommy Braas wrote:
Bill and James,
Thank you very much for your answers!
I have one more question;
Does the 'complex' part of the AudioConverterFillComplexBuffer pertain
to the buffers being complex (AudioBufferList*), or that it expects
the values to be complex? Maybe a dumb question, but since the
documentation leaves much to be desired, I feel compelled to ask.
Thanks again,
Tommy Braas
On Friday, Jun 6, 2003, at 11:31 US/Pacific, Bill Stewart wrote:
And we've fixed this in our next release - we'll be returning an
error for these invalid uses of convert buffer (something we should
have done but missed in Jaguar)
You might also look at the FillComplextBuffer version - if you are
working with audio units (the V2 variety) then this takes and returns
the data strcuture (AudioBufferList) that is used by these units...
(If you're using a V1 unit, then the FillBuffer call is the
appropriate one) - and if I'm confusing you - apologies! I'm confused
myself sometimes:-)
Bill
On Friday, June 6, 2003, at 07:28 AM, James McCartney wrote:
You should not use AudioConverterConvertBuffer when you have a
sample rate conversion. Use AudioConverterFillBuffer or
AudioConverterFillComplexBuffer.
Because in a sample rate conversion the output samples depend on
samples before and after them from the input, there is some internal
buffering that must happen which requires that you use the pull
model of these other conversion routines.
AudioConverterConvertBuffer is only for conversions where there is a
1:1 correspondence between input and output such as bit depth,
endian swap, int<->float, (de)interleaving...
On Friday, June 6, 2003, at 01:00 AM, Tommy Braas wrote:
I have been trying to figure out how to properly feed an instance
of AudioConverter using AudioConverterConvertBuffer(...).
-- --- james mccartney
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