So many codecs,
For audio, whatever codec, finally, it should be decode to wav form to output, right?
When codec based data be converted to wav, we can check its different with original wav data, right?
For Video, it's the same.
Does that not a way to verify difference ?
Best regards, Boki.
Yes, You can subtract the audio that has been processed from the original and listen. This will give a general idea of the codec quality. It is very difficult to put a value on the signal degradation in numeric form that means anything (IMHO)
Try snell and wilcox web site for video information
martin
It'll give the mathematical difference for sure. It would certainly be interesting to listen to ! I'm unsure how effectively it would be in rating the psycho-acoustic effect of different codecs though.
Graham
Un bel giorno Pooh Bear digitò:
I would say "near zero". It has been shown that either time- and frequency-domain comparisons are ineffective. Double blind listening tests seem to be the correct way. This is one of the advocates of this technique:
-- asd
Thanks a lot for information.
Best regards, Boki.
If we don't care the human ear avalible range ( 20~20K), it is a mathematical result. umm. .. I want to say,
If we calculate that, we can know whcih codec has less lost, isn't it ?
Best regards, Boki.
In a mathematical sense - yes.
That may not correlate well to the effect perceived by human hearing though.
Your idea is very interesting though. If you choose to develop it, I would be very interested to hear the results.
Graham
haha... in fact, I think that is a time problem, but the more important I want to care is the final result is useful or not.
About 2~3 years before, I was developing Video/Image processing, I think the numerical difference didn't get too much sense for human eyes, certainly it is a reference.
I think we don't have to pay effort on the data processing, we have so many sound tool in our world already, just read them ( decoded mp3/wmv/...) from our program to calculate what we want.
It seems that something is related to ART :D
Best regards, Boki.
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