I am currently working on waveform interpolative speech coding. I
exploit the usual scheme, but it doesn't provide accurate (perfect)
waveform reconstruction even when using no quantization. Does anyone
know any papers/info about perfect reconstruction for waveform
interpolation coder? Please advise.
waveform interpolation coder with accurate reconstruction
Unlike the speech coders from the CELP-family WI is a parametric
coder. The more bits you "invest" in CELP-like coder the higher
accuracy of the waveform reconstruction, but it is not so for WI. WI
strongly depends on pitch detection accuracy, CW-alignment and
CW-decomposition; if these procedures fail (completely or partially)
any amount of bits for SEW/REW quantization (including
non-quantization) will not help you. Even if in addition to
non-quantized SEW- and REW-amplitude spectra you transmit original
SEW- and REW-phase spectra (which is not interesting for commercial
WI) you still cannot get a perfect reconstruction of the waveform
because the initial phase in phase-tracking procedure is arbitraty.
So, don't judge your coder according to accuracy of the waveform
reconstruction. Try to focus on the following most annoying problems:
1. Good pitch detector
2. Good CW-alignment algorithm
3. Good CW-decomposition algorithm
For quality measurement use PESQ or PSQM. The following paper might
C.H. Ritz, I.S. Burnett and J. Lukasiak, "Extending Waveform
Interpolation to Wideband Speech Coding", 2002 IEEE Speech Coding
--- In , "empush2000" <mpush2000@m...> wrote:
> Hi everyone,
> I am currently working on waveform interpolative speech coding. I
> exploit the usual scheme, but it doesn't provide accurate (perfect)
> waveform reconstruction even when using no quantization. Does anyone
> know any papers/info about perfect reconstruction for waveform
> interpolation coder? Please advise.
> Thank you.