[Osalp-dev] aflibConverter question

[Akos M. <da...@ty...>]

Hi,

I'm trying to use the class aflibConverter from OSALP to do some raw 
audio data resampling. And I can't get it to work. I read through the 
documentation for the class at 
http://osalp.sourceforge.net/doc/html/class_aflibConverter.html
but could someone please elaborate more on the parameters to the 
aflibConverter::resample() function? In particular:

- is inCount an output only parameter, or is it in/out?
- in inArray, should I supply a 2 channel input with channels interleaved?
- will the outArray contain them interleaved?
- for inCount / outCount and the return value: a value of n means:
     - n * channels values in the actual array?
     - n values in the actual array?

For example:

aflibConverter    * converter = new aflibConverter( true, true, false);

converter->initialize( 0.5, 2);

short      inArray[2048];
short      outArray[1024];
int        inCount = 2048;
int        outCount = 1024;

// suppose inArray contains two channel interleaved raw audio data of
// 1024 samples

int converted = converter->resample( inCount,
                                      outCount,
                                      inArray,
                                      outArray);

after this call I get 2048 for inCount and 1024 for the return value. 
But the data in outArray[0 ... 1024] is no good, if I save it to a file, 
it's not proper .wav data:

$ file result.wav
result.wav: data
$ play result.wav
sox: WAVE: RIFF header not found

I'm trying to get it work, but so far only resampling with a factor of 1 
gives me any useful results (which is of course quite useless :). Any 
help would be appreciated.


Akos