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Intepretation of results of blind test, When it's possible to say if codec is transparent or have a good q
post Nov 28 2008, 02:31
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I'm curious about how it's correct to interpret the results of blind tests.

For example average scores of two competitors are A=4.5 and B=4.7
First of all statistcly speaking they are tight. But let's suppose they were enough samples as to discard this statistic interval.
I know it's not about mathematics but more about practical approach wich filosofy is way different but there are my thoughts:

Mathematical interpetation
On one hand A - 4.5/5 = 90% of "quality" and B - 4.7/5= 94%.
1st type of interpretation. 94/90 = 1.0444...
Codec B is better than A by 4.444...%

2st type of interpretation. The codec A has 90& of quality (full transparency) then it has 10% of perceptible difference (artifacts) while codec B has 94% of quality and 6% of perceptible difference.
Then Artifacts(A)/Artifiacts(B) 10%/6% = 1.666... .
Codecs B is better than A by 1.666..x times.

In my opinion 2st type of interpretation is more close to real reflection of listeting experience as people remeber mostly artifacts and don't notice a good job of codecs.

Psychological interpretation
When can I say quality is transparent? 5.0? Or less? 4.9,4.8...?
I can speak only about me in this case. I will put a X mark for one particular sample
1. 5.0 - undistinguish from original
2. 4.9 - I doubt if I ever will hear the difference again or if I actually hear it at all.
3. 4.8 - Well I hear the difference, but it was too hard and requiered a lot of concetration
4. 4.7 - The sample isn't transparent at all but the quality is high. And it's point for me to say "not transparent"

So this way codec is transparent (or extremely close to transparent) for me if the average score is at least 4.8 (Psychological interpretation)

While for mathematical (and/or statistioc) intepretation 95% is a good approximation. So 5 * 95% = 4.75 is minimal score for imaginary transparency.

Any comments and thoughts about your personal experience are welcomed.

If someone has already discussed it then please give the link.

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