I have noticed that there are many projects that reproduce the same sample conversion routines for changing sample rate / frequency / endieness / channels. Of the top of my head: esd/arts/xmms/madplay/ libaudiofile.
Perhaps there is already such a library, but if not I was hoping that this could warrant the creation of a second 'companion' library to mad (libresample or something). It could also contain down mixing routines for combining channels.
just a thought
sam
Yes, and Erik de Castro Lopo has just written a very nice resample routing for the newest version of libsndfile.
I would very much like to see a small, portable "libresample".
Maybe resample isn't the best title, because it would make sense for it to encompass changing both sample size (16-bit, float) and sample rate.
- Dominic
Sam Clegg wrote:
I have noticed that there are many projects that reproduce the same sample conversion routines for changing sample rate / frequency / endieness / channels. Of the top of my head: esd/arts/xmms/madplay/ libaudiofile.
Perhaps there is already such a library, but if not I was hoping that this could warrant the creation of a second 'companion' library to mad (libresample or something). It could also contain down mixing routines for combining channels.
just a thought
sam
On Fri, May 03, 2002 at 08:56:29AM -0700, Dominic Mazzoni wrote:
Yes, and Erik de Castro Lopo has just written a very nice resample routing for the newest version of libsndfile.
I would very much like to see a small, portable "libresample".
Maybe resample isn't the best title, because it would make sense for it to encompass changing both sample size (16-bit, float) and sample rate.
Can't changing the sample size be viewed as resampling in some sense?
Sam Clegg wrote:
On Fri, May 03, 2002 at 08:56:29AM -0700, Dominic Mazzoni wrote:
Yes, and Erik de Castro Lopo has just written a very nice resample routing for the newest version of libsndfile.
I would very much like to see a small, portable "libresample".
Maybe resample isn't the best title, because it would make sense for it to encompass changing both sample size (16-bit, float) and sample rate.
Can't changing the sample size be viewed as resampling in some sense?
Sure, why not? I think that when most people use the word "resampling" they're referring to changing the sample rate. Changing the sample size is trivial unless it involves dithering, therefore the library would be a "resampling and dithering" library.
I don't care what we call it - I'd just like to see people collaborate on the library instead of everyone writing their own resampling and dithering routines into their libraries. I've heard discussion of these routines being provided in future versions of libmad, libsndfile, and portaudio already.
- Dominic
On Thu, May 16, 2002 at 10:06:39AM -0700, Dominic Mazzoni wrote:
Sam Clegg wrote:
Can't changing the sample size be viewed as resampling in some sense?
Sure, why not? I think that when most people use the word "resampling" they're referring to changing the sample rate. Changing the sample size is trivial unless it involves dithering, therefore the library would be a "resampling and dithering" library.
I don't care what we call it - I'd just like to see people collaborate on the library instead of everyone writing their own resampling and dithering routines into their libraries. I've heard discussion of these routines being provided in future versions of libmad, libsndfile, and portaudio already.
Hmm, I think getting the name right seems to be the hardest part at the moment ;)
There is a new project on sf.net started my myself and a few people working on asd (think better esd). At the moment it's just called 'libsample', but I think we are going to rename it to 'libresample' or 'libpcm' (although it will support alaw and ulaw, hmmm).
What we hope to do is bring together all the existing resampling routines and make them accessible through a simple unified API.
We're starting with these two: http://ccrma-www.stanford.edu/~jos/resample/ http://www.atri.curtin.edu.au/~ajh/resample/
Check out http://libsample.sourceforge.net/. At the moment there is only one simple linear interpolation algorithm implemented. Anyone who wants to help is welcome to CVS access.
samo
On Thu, 16 May 2002 10:06:39 -0700, Dominic Mazzoni dominic@minorninth.com wrote:
Hi,
I don't care what we call it - I'd just like to see people collaborate on the library instead of everyone writing their own resampling and dithering routines into their libraries. I've heard discussion of these routines being provided in future versions of libmad, libsndfile, and portaudio already.
Why not asking Naoki Shibata? He wrote SSRC (http://shibatch.sourceforge.net/). Sadly it's not usable as a library, else it would be in winLAME for long.
bye Michael
-
Dominic Mazzoni -
Michael Fink -
Sam Clegg