Automatic Sound Signals Quality Estimation. Integration. (2/2)
To Audio Codecs Quality Analyzer page
Example 1: codec quality estimation
Let’s take two codecs from Voiceage web page that are freely available for testing purposes:
http://www.voiceage.com/freecodecs.php
• Open G.729
• Open AMR (narrowband)
The following steps are applied when one likes to test audio codec quality using our software:
1. Create a voice model for codec testing (source voice file, for example in PCM format) using our software
2. Encode it with ANY codec
3. Decode the encoded voice back into raw PCM (using the same codec)
4. Compare original and uncompressed PCM files with our software
Voiceage G.729 test results:
Our software: MOS 4.17
Cisco MOS: 3.92*
This corresponds to Cisco score by 94%!
Voiceage AMR narrowband test results:
Our software: MOS 3.93
PESQ MOS: 3.847*
This corresponds to PESQ by 97%!
Example 2: we catch audio quality loss when PESQ fails!
The following article describes situation when ITU P.862 standard fails to detect voice quality loss:
http://www.microtronix.ca/pesq-disc.html
The article presents a voice file that was equalized such that there is far less low frequency and high frequency energy when compared to the original file thus making it clearly audible that the speech file is degraded when you listen to it, but PESQ reports that the quality between degraded file and the original are the same!
Test results of our software applied to Microtronix files:
• dg001.wav -> 4.7 (4.96) MOS (94% similarity in our units)
• dg002.wav -> 1.29 (0.73) MOS (26% similarity in our units)
This example clearly shows that our software does catch that significant quality loss, which occurs when the file is equalized with far less low frequency and high frequency energy.
Software customization
In 2009 we offer offshore prices for voice quality software customization!
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