Can any one suggest me How to compare two MP3 encoders for audio quality?

How Audio quality is measured?? Is there any tool to measure how much MP3 encoded and MP3 decoded audio file differs from the original audio file? (.wav vs .wav->.mp3->.wav)
Is there any other measurement criteria for audio quality than listening tests?

I came across EAQUAL tool which claims that it is based on ITU-R recommended BS.1387 audio quality standard for objective quality measure. anybody knows how accurate results it gives?

Is it right to compare with this tool?? Is there any other tool for audio quality measurement?

Thanks and Regards,
Satya

Regarding psychoacoustic audio compression, the only way of measuring quality is via subjective listening tests, performed in a blind fashion in order to have good reliability.

EAQUAL can give some orientative results, but it is not very accurate, and not a substitute for a real human ear.

KikeG is right. None of the so called 'objective' sound quality assessment tools that try to model how human hearing works are a good substitute for subjective listening tests.

What complicates the issue even more that a lot of human hearing (esp. neural processing) is relatively unknown for complex sounds.

Most of the dual stimulus sensory evaluation methodologies have been developed for olfactory senses and as such may not offer the lowest amount of test noise, because hearing works differently from taste/smell (on the neurological level).

But if you want to try, get a program that helps with doing a basic subjective listening tests:

http://ff123.net/abchr/abchr.html

Of course, using a utility isn't the same as knowing how to set up a proper psychoacoustic listening test with properly controlled variables.

You can get more information from the following ITU-R Recommendations that help with some of the basics of subjective listening evaluation:

BS.1116
Methods for the subjective assessment...

BS.1283
Subjective assessment of sound quality...

BS.1284
Methods for the subjective assessment of sound...

BS.1285
Pre-selection methods for the subjective assessment...

BS.1387
Method for objective measurements of perceived audio quality

Please be advised that each reprint costs costs c. 22 CHF, but a local technical university library might have a license through which you could peruse the publications for free.

You can order the ITU papers online at:

http://www.itu.int/rec/recommendation.asp?...parent=R-REC-bs


Best regards,
Halcyon

In case you didn't see my last reply on the monkey forum: here it is - there are a few links to older discussions of EAQUAL.

(if you saw it already - no problem, either way)