[Speex-dev] Speex for sampling freq >48KHz

devilal sharma devilal_sharma at yahoo.com
Mon Mar 27 00:18:00 PST 2006


Hi Jean-Marc Valin,
Thank you for your suggestion. I am shifting to using Vorbis for Audio. I was using speex because I was using speex for previous work and it was easy to continue on speex than shifting to vorbis, not only that but speex is a waveform coder and I get quite good waveform matching when I reconstruct back the waveform using Speex even for music upto 44.1KHz. 
My motive is to get a lossless coder out of this(I am aware of FLAC). I want to compress and decompress the .wav file and then get the residual signal which I want to entropy encode using some program i have. I just want to use Vorbis(I was using speex till now) to get the smallest possible residual signal. 
The question is this that whether Vorbis will get me the waveform matching and the residual signal small enough?
So please tell me how to go about it.
I have downloaded libvorbis-1.1.2 and trying to compile it. Please tell me how should I use it to compress and decompress files for above use.

Thanks,
Regards,
Devilal

Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> wrote: > I was just trying to use speex for sampling frequency >48KHz. In the
> original Speex-1.0.5 its restricted only upto 48KHz. I tired to modify
> it by changing the boundary conditions( the error conditions, i.e. if
> sampling freq >48KHz, it gives error) in /src/speexenc.c and then it
> atleast doesnt give the error, there is flow in decoding or encoding(i
> think).
> I suspect there are other constraints in the encoder and decoder to
> modify other than this to make it work properly.
> At this point, I am not getting the proper decoded(reconstructed)
> bitstream. 
> Can you please suggest me the places where I should make changes to
> incorporate this requirement.

OK, I'm not sure what exactly you're trying to achieve, but I can't see
any sane reason to use Speex at > 48 kHz sampling. I already think 44.1
kHz is a bad idea. If you want high-fidelity, use Vorbis, not Speex. If
you want decent quality speech, use Speex at 16 kHz or something like
that.

 Jean-Marc



		
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