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Speex questionairres
tech_noobie
post Sep 22 2005, 06:30
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Hi everyone, I have got yet more questions about Speex, I am sorry if my questions are too newbie:

1. For the LP analysis, did Speex use the AR (Autoregressive) model or the ARMA model?

2. Am I right to say that Speex use a multistage VQ (since I believe Speex employs two or more VQ consecutively - based on the manual it says that Speex uses dynamically selectable codebooks (linear prediction,pitch prediction and innovation))?

3. It is said in the manual that Speex also use sub-vector fixed (innovation)codebooks, does this mean that it also utilises a Split VQ?

4. In the part about innovation codebook, it is said that the final excitation signal would be made up of the innovation signal and the pitch prediction, I presume that by final excitation signal it meant the output signal that Speex will produce (Is this correct btw?) but what does innovation signal refers to? It is said that it represents information that couldn't be obtained from either linear prediction and pitch prediction, but what is it actually? (I have tried to look at the code, but I am not that good at reading codes crying.gif )

5. Speex is a CELP-based coder, so I believe that it utilises both Spectral analysis and Fourier analysis (FFT) during the LP analysis, Am I right?

Once again, I am very sorry if my questions are too newbie unsure.gif , Thank you very much for your time.

tech_noobie
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kjoonlee
post Sep 22 2005, 08:02
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Just FYI, a subscription to the speex@xiph.org or speex-dev@xiph.org mailing list would be very helpful, I think.


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http://blacksun.ivyro.net/vorbis/vorbisfaq.htm
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tech_noobie
post Sep 22 2005, 08:27
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Hi Kjoonlee,

Thanks for the advise, believe it or not, I have just subscribed to the forum you suggested, just before I read your message. Thank you very much for your kind reply biggrin.gif .

But ... just in case, if anyone can answer any of these questions, I would be happy to hear it from you guys biggrin.gif .

This post has been edited by tech_noobie: Sep 22 2005, 08:29
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