Re: AudioConverter fails on SRC when formats are float -> float
Re: AudioConverter fails on SRC when formats are float -> float
- Subject: Re: AudioConverter fails on SRC when formats are float -> float
- From: William Stewart <email@hidden>
- Date: Tue, 14 Oct 2003 10:49:21 -0700
On 14/10/2003, at 4:30 AM, Holger Hoerich wrote:
Hi,
I'm using AudioConverter to do sample rate conversions and format
conversions if necessary. I'm stuck at a point where the sample rate
conversion works when doing format conversion at the same time and it
works also if no conversion is required at all. But I cannot do sample
rate conversion for float input. I don't know what I'm doing wrong
here.
The application is derived from DefaultOutputUnit example. A render
function is the callback function of the default output unit. This one
calls AudioConverterFillBuffer and provides a decoder function as
callback. I have to give the converter one chunk of 2048 samples which
I return from an audio decoder in the callback function of the audio
converter.
Which the converter will buffer internally, and only ask you for more
when it has finished processing your input.
What I see is that for he examples which work the render function is
called multiple times because of the large input buffer the converter
gets before the decoder is called again
right....
but the the float to float with sample rate conversion the decoder is
called everytime the render function is called but should be called
only every 4th time (?)
No - the output unit will only ask you for as much data as is needed to
be produced for that given slice of audio output for the device. You
also can't give it *more* (AU's are essentially in this usage modeling
real-time behaviour)
I'm not sure that I completely follow your signal chain construction -
but the converter will buffer data internally, and only ask for data
when it has no more input to process - this is driven by the output
side of the converter (ie. how much data you ask it to produce)
Bill
I would appreciate any help!
Holger
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