Re: AudioConverterFillComplexBuffer for rate conversion?
Re: AudioConverterFillComplexBuffer for rate conversion?
- Subject: Re: AudioConverterFillComplexBuffer for rate conversion?
- From: Michael Thornburgh <email@hidden>
- Date: Sun, 25 Apr 2004 15:56:56 -0700
it's not safe to write more data into audio buffers that you've passed
into an AudioConverter from your AudioConverterComplexInputDataProc
until your AudioConverterComplexInputDataProc has been called for more
data, indicating the previous data has been consumed.
so if your program sequence is:
read some samples into aBuffer
call AudioConverterFillComplexBuffer()
yourAudioConverterComplexInputDataProc() called by ACFCB()
link aBuffer into ioData
write converted samples to a file
repeat
then you can get glitches, because the AudioConverter might not be
entirely done with all of the samples from aBuffer before it's
overwritten.
instead, make your program sequence be:
call AudioConverterFillComplexBuffer()
yourAudioConverterComplexInputDataProc() called by ACFCB()
read some samples into aBuffer
link aBuffer into ioData
write converted samples to a file
repeat
that way, you're not changing anything in aBuffer until you know the
AudioConverter has used up the last sample from the previous fill.
-mike
On Apr 25, 2004, at 3:30 PM, Ev wrote:
I've started using AudioConverterFillComplexBuffer for rate conversion,
but I'm having some issues between buffers.
Obviously I don't convert the whole file in one go, I use buffers of a
good size, then pass them to AudioConverterFillComplexBuffer for
conversion, then write them to the file.
Passing a good test tone through seems to create a glitch at the
BEGINNING of each NEW buffer. You can hear the buffer beginnings in
this example:
http://www.audiofile-engineering.com/997Hz_-6_48k.aif
Is this an expected side effect of this technique? Is there something I
can do?
Ev
Technical Knowledge Officer
Head Programmer/Designer
Audiofile Engineering
http://www.audiofile-engineering.com/
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