[speex-dev] How suitable is speex for high-quality speech?

[Jean-Marc Valin]

Hi,

I think Speex is probably suitable for your application. The 8 kHz
bandwidth (16 kHz sampling rate) covers most of the frequency content of
speech. You can try down-sampling some samples to 16 kHz if you like to
hear the difference. Also, at higher bit-rates you won't tell the
difference between the encoded version and the original. 

If 16 kHz doesn't do, I'm currently working on a 32 kHz mode which could
help. That mode will likely be included in the next release (beta 3). As
for the choice between Speex and Vorbis, I'd say it depends on the
input. Speex is meant to encode voice, while Vorbis is more general but
mostly oriented toward music. The Speex bit-rate is lower and requires
less CPU, but if you try encoding music with it, the quality will be
bad.

        Jean-Marc

Le lun 04/11/2002 à 18:32, Philip Jägenstedt a écrit :
> Hi!
> 
> Having had a look at speex I have understood that the primary aim is to provide speech compression for low-bandwidth things such as VoIP and whatever. Also, the fact that the highest frequency (wb mode) is 16kHz makes me wonder if...
> 
> The REAL question:
> Would speex be useful for storing the voices for characters in a game or for storing other voice recordings with high quality? I do not know very much about digital audio, but is it not true that with a samplerate of 16kHz high frequencies would sound a little flaky? (If one of the character should scream in a silly way or something). And will speex preserve the "dynamics" of the audio - if you know what I mean (I'm not sure I do), the smoothness and so on. Since I don't presently have access to a million dollar microphone to do some real tests with I am directing these questions to this mailinglist.
> 
> Summary: is speex good for the said application, or would vorbis be more appropriate when it comes to this?
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-- 
Jean-Marc Valin, M.Sc.A.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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