Hi,everbody:
I'm studing document of AMR-WB(G.722.2).I have found that there hasn't the post-processing in decoder. I know the technic of post prosessing which is supposed after reconstructing speech can improve the quality of reconstructed speech .
In AMR-WB, there just has some process to adaptive codebook ， fixed codebook and gains.
Dose anybody can help me about why AMR-WB needn't post-processing ?

It's quite possible that they didn't put post-processing into AMR-WB standard. I don't have the technical specs with me at the moment so I'll check them tomorrow.

amr-wb is mainly used for wireless communication, right? in addition, for wideband.
I have read some papars, and found that most narrowband communication use post processing, but for wb, they just adjust the gain in CLEP
Does it have some relation to bandwidth?

What post processing technic do you mean?

a processing aims at background noise

Most probably, you will have no problem in adding additional processing at the decoder.

Most post-processing in CELP coders involve cascading a long-term and short-term postfilter as well as compensating for gain and reducing spectral tilt. The short-term postfilter emphasises formant peaks and attenuates spectral valleys between formants, while the long-term postfilter emphasises pitch harmonics. It makes the reconstructed speech sound better.

As to why they haven't applied it to wideband coding, I'm not too sure. Perhaps, the existing AMR-WB didn't suffer from the quality problems of narrowband CELP. (and I seem to have forgotten to look up the tech specs, as promised in my earlier post lol)

OK, now browsing the tech specs of AMR-WB decoding. There is some post-processing in the lower bitrate modes (6.60 and 8.85 kbps) such as anti-sparseness processing, noise enhancement, pitch enhancement, etc.