http://www.signalogic.com/index.pl?page=codec_samples
SEE ALSO FOR RESEARCH :Reciprocal mode saw correlator method and apparatus
US 5355389 A https://encrypted.google.com/patents/US5355389
SEE ALSO FOR RESEARCH :
US 5355389 A https://encrypted.google.com/patents/US5355389
Below are a variety of "before and after" .wav file samples for different LBR (low bit rate) speech (voice) codecs, including MELP, GSM, and G.729A/B, with bit rates ranging from 600 bps to 13000 bps. Click on the .wav file links to hear the samples. All .wav files are mono, sampled at 8 kHz.
Speech samples are at left, with different codec types across (columns). Each row is a different language or sample type, such as addition of background noise. In several cases, a language sample may include both male and female speakers.
Underneath each sample is given the PESQ score, which is a numerical algorithm comparison between the original sample and the processed sample designed to closely approximate a MOS score. 4.5 is a perfect PESQ score, meaning there was no degradation of the processed sample from the original sample. PESQ scores normally refer to the "Original" sample at far left column, unless otherwise indicated. More information on is given below.
Speech Codec Samples
Numbers given in () below the codec type are inherent algorithm frame size (delay) values, given in msec.
| Fs = 8 kHz (128000 bps) | 2400 bps (22.5 msec) | 2400 bps (22.5 msec) | 1200 bps (67.5 msec) | 2400 bps (22.5 msec) | 2700 bps (20 msec) | 4000 bps (20 msec) | 600 bps (30 msec) | 8000 bps (10 msec) | 13000 bps (20 msec) | 2400 + AT&T NPP4 | 8000 bps + AT&T NPP | 13000 bps +AT&T NPP | 13000 bps +AT&T NPP | 13000 bps +AT&T NPP | |||||||||||||||
Language & Score | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | Female | |||||||||||||||
English1 | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | 4.5 | 4.5 | 2.673 | 2.293 | ||||||||||||||||||||||||||
English2 | ||||||||||||||||||||||||||||||
(ITU) PESQ1Score | 4.5 | 4.5 | 2.666 | 2.445 | 2.86 | 2.583 | 2.413 | 2.323 | 2.923 | 2.704 | 2.958 | 2.734 | 3.266 | 3.078 | 3.570 | 3.265 | 2.583 | 2.434 | 3.254 | 3.076 | ||||||||||
French | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | 4.5 | 4.5 | 2.401 | 2.549 | 2.482 | 2.575 | 2.249 | 2.365 | 2.786 | 2.756 | 2.770 | 2.829 | 3.162 | 3.243 | 3.349 | 3.352 | 2.482 | 2.599 | 3.343 | 3.315 | ||||||||||
German | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | ||||||||||||||||||||||||||||||
Japanese | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | ||||||||||||||||||||||||||||||
Chinese | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | 4.5 | 4.5 | 2.781 | 2.572 | 3.080 | 2.769 | 2.738 | 2.477 | 3.120 | 2.739 | 3.124 | 2.809 | 3.490 | 3.164 | 3.730 | 3.601 | 2.969 | 2.641 | 3.548 | 3.462 | ||||||||||
NSA test vector5 | ||||||||||||||||||||||||||||||
(ITU) PESQ Score | 4.5 | 4.5 | 3.185 | 2.963 | 3.270 | 3.063 | 2.976 | 2.761 | 3.331 | 3.029 | 3.330 | 2.963 | 3.637 | 3.451 | 2.694 | 2.275 | 3.882 | 3.901 | 3.197 | 2.988 | 3.865 | 3.659 |