Even now and then we get questions on how AQuA is similar / different to PESQ. Well, AQuA surely differs from PESQ, because it’s using different perceptual model, returns different parameters (AQuA returns prediction for objective MOS score according to P.800 and PESQ values are from 1 to 4.5 considering that nobody can distinguish MOS 4.5 and MOS 5), has different features, provides more information on reasons for audio quality loss.
We clearly state that AQuA is not PESQ. There are cases which PESQ fails to detect, but AQuA does catch the degradation, read this article Perceptual Evaluation of Speech Quality (PESQ), and there are reports that state PESQ may not give accurate scores for example in mobile and VoIP end-to-end testing (you can google for “Limitations of PESQ”). However, the point is not that AQuA is better than PESQ, it’s just different, but different in many ways.
We created AQuA to provide VoIP community with inexpensive tool to measure and monitor voice quality in VoIP, mobile, PSTN and converged networks. Currently we have customers that use AQuA for all types of networks including sattelite communications and they are quite happy, because the main point is that one needs to know whether the quality is good or bad and if a tool delivers this information at a certain precision then it’s useful.
When evaluating voice quality in VoIP or other communication network our customers report two main issues:
1. test signal may have different level (RMS amplitude) than the original, and in this case it requires amplitude adjustment that is done by free SOX utility in AQuA 5.x. AQuA 6.x that is ready for release has built in feature to adjust RMS amplitude using our in-house algorithm.
2. test signal may have “silence” in the beginning and / or end of the recorded audio file. In order to synchronize two signals in time domain one can use SOX as well, or use -trim parameter in AQuA, or even both.
There are a lot of parameters one can adjust in AQuA, but in most of the cases they are set to default values and we deliver batch scripts for Windows and Linux with pre-set parameters. Typical test then looks like
Windows: test.bat reference.wav test.wav
Linux: ./test.sh ./reference.wav ./test.wav
To summarize AQuA and PESQ do the same thing differently. If one requires to provide its end customers voice quality score accordoing to International standard, then it’s surely PESQ, because it’s a recommendation from ITU-T P.862/P.863 bla bla bla that costs a lot of money and is provided by different companies as a software / hardware combination, boards, features, bla bla bla… And if you are a VoIP service provider or a mobile operator or DSP algorithms developer then AQuA is your best choice – no royalties, no specific hardware (you want a dialer connected to E1/T1, GSM or sattelite network? then use Asterisk VQM – open source based voice quality monitoring soluton) – just pure voice quality assessment.
If you have questions you are always welcome to contact us!