How About Ac-3 Quality ?

2002-10-05 21:05:09

Hi !
What do you think about AC-3 in terms of pre-echo  ?
Does it performs really worse than other competitors ?

Best Regards,
Nick

How About Ac-3 Quality ?

Reply #1 – 2002-10-05 21:21:56

I think it performs better than MP3 and OGG in terms of pre-echo.
Compared to AAC i really don't know. Compared to MPC, no way.

How About Ac-3 Quality ?

Reply #2 – 2002-10-05 22:35:46

I don' know about pre-echo specific but somebody wise on this board (or was it doom9) told that it was around mp2 level. E.G. mp3 and vorbis are better quality if the source is the same.

How About Ac-3 Quality ?

Reply #3 – 2002-10-05 22:53:51

this thread

How About Ac-3 Quality ?

Reply #4 – 2002-10-05 23:03:02

Keep in mind that none of the AC-3 encoders used for testing the quality are good. A good hardware AC-3 encoder has far better quality than any software AC-3 encoder. So no software AC-3 encoder truly shows the true potential of AC-3.

How About Ac-3 Quality ?

Reply #5 – 2002-10-05 23:10:59

Why should a good hardware AC3 encoder be better than any software encoder?
I don't get it. What about a software simulation of the best hardware encoder? Shouldn't it be on par with the hardware device at least?

How About Ac-3 Quality ?

Reply #6 – 2002-10-05 23:18:14

It is untrue for the hardware - that situation was in early 1990's when reference codec implementations were done in DSP hardware.  Nowdays, initial best quality codec implementations are done in plain-C  and they do work on any PC - some of them are unable to run in real-time, but that was not the point.

Regarding AC-3 - we could only discuss whether AC-3 encoder used by Dolby internally is better than other third-party encoders. I haven't done any research on the issue, but I suppose that Dolby could have "better" AC-3 encoders than  code available for licensing to software companies.

Also, AC-3 is very limited in expansion, because it uses bit allocation which is assumed by decoders - so part of the psych. model is in decoder, too -which prevents some radical changes to bit allocation approach.

How About Ac-3 Quality ?

Reply #7 – 2002-10-05 23:25:44

Thanks for the info Ivan..
Yeah, so the problem is actually that Dolby could have better AC-3 encoder code than the one offered to software companies. I really wonder why they don't...

(good to see you here. can't wait for some info on the aac developments )

How About Ac-3 Quality ?

Reply #8 – 2002-10-05 23:34:07

AC3 vs. MP2 vs. MP3 vs. AAC vs. PAC  - at Dolby's site:

http://www.aac-audio.com/technology/aac.rp...2.xprtLsnr.html