Hello,

The average lenght of WMA 9.2 Standard VBR Quality 10, 25 and 50 files
seems to be even shorter than WMA 9.1: is it possible?

With 9.2 VBR Quality 10 I get an average bitrate of 50 kbps (nominal),
that is actually 45 kbps if I calculate it as Kbyte*8/seconds. Cutoff frequency seems to be at 12 kHz.

With 9.2 VBR Quality 25 I get an average bitrate of 62 kbps (nominal) that is actually 55 kbps (calculated). Cutoff frequency seems to be at 13 kHz. (With classical music, I get even lower bitrates)

With 9.2 VBR Quality 50 I get an average bitrate of 82 kbps (nominal) that is actually 75 kbps (calculated).
Cutoff frequency seems to be at 13.2 kHz. (With classical music, bitrates are even lower)

With 9.2 VBR Quality 75 I get an average bitrate of 125 kbps (nominal) that is actually 110 kbps (calculated).
Cutoff frequency seems to be at 15.5 kHz.
This is a big leap from Quality 50 (I would like something in between, around 90-95 kbps).

Coming to 9.1 Quality 25: I don't have this codec, but I read a few posts and web pages about it:
it seems that the average bitrate is 80 kbps or more, from the this test (year 2005):
http://www.hydrogenaudio.org/forums/index....showtopic=35438

And about 9.1 Quality 10, I calculated an average of 54 kbps from the sample files I found at this web page:
http://js.jino-net.ru/js-music-demos-english.htm

So, are 9.2 VBR files shorter than 9.1, at the same Quality?

And what about CBR?
By the way, is WMA 9.2 CBR 96 kbps (with a cutoff frequency around 15 kHz) better than WMA 9.2 VBR Quality 50?

And finally, what about WMA 9.0?

Thanks

ipotesi
Italy

P.S.
9.2 VBR Quality 25 seems to be the same as VBR 40/75 kbps while ripping CD's from Windows Media Player 11.
9.2 VBR Quality 50 seems the same as VBR 50/95 kbps from Windows Media Player 11.
9.2 VBR Quality 75 seems the same as VBR 85/145 kbps from Windows Media Player 11.

Previosly I thought that WMA didn't change significantly from 9 to 9.2; so I decided to encode several songs with WMA VBR of different versions: WMA 9/WMA 9 Pro (WMP 9), WMA 9.1/WMA 9.1 Pro (WMP 10), WMA 9.2/WMA 10 Pro (WMP 11). Here are average bitrates (in kbps):


About bitrates: WMA 9 and WMA 9.2 are very close while 9.1 produces significantly bigger files.
About quality: didn't tested thoroughly but compared WMA9 Q50 (avg. bitrate 78 kbps), WMA 9.1 Q25 (86 kbps), and WMA 9.2 Q50 (79 kbps). Found several artifacts that exist both in 9 and 9.1 versions but disappear in WMA 9.2.

Great! This is a full explanation of the supposed contradictions I noticed.
I am restricting your table to the Standard WMA 9.x and up to Quality 75, which are the most interesting ones for my purposes:



I would go with WMA 9.2 Quality 50, that sounds good to my ears (and to yours, as you reported).
The only think I don't like is that the cutoff frequency is only 13200 Hz and I wonder how better it could have been with a cutoff frequency around 15000 (or at least 14000 Hz).

Thanks for you help,

ipotesi

People often find themselves asking for "more for less", as in wanting to have more of something (frequency, money, sex) giving less in return (bitrate, work, sexyness).

Want to know how would have been with a higher frequency? use a higher setting -> use a higher bitrate.

Want to have the same bitrate? Then expect the quality to degrade.


Sincerely. Sound quality, with lossy codecs, is not about bandwidth frequency. It is about not introducing artifacts. The capability to hide better the artifacts is what lets the frequency be higher.

I still pull my hairs when I hear some 64kbps WMA 9 encodes here and there (and sadly, sometimes even on FM radio). Microsoft pretended it to be comparable to CD audio, they put a high frequency cutoff pretending to show the codec could do better

And the truth?

It does worse. It may pretend to be a horse, but it is still a pig (let's not talk abou lipstick).

As I explained in another forum (Mp3 General) it is really a matter of average bitrate for me, because I have a collection of music divided by genres, and each genre has around 18-20 hours of music: so it would be good to fit each genre into a single CD, which would happen just under 100 kbps.

The WMA VBR Quality 50 setting seems the best to achieve that goal, and goes even too low, at around 80 kbps. This setting has a cutoff frequency of 13.2 kHz. Actually it is not a problem for my ears (as I said before in this thread), but I know that some people, with ears better than mine, would notice that cutoff (if/when they will happen to listen with me to those compressed files). It's a very minor problem. (Something in between Quality 50 and 75 would have been perfect, avoiding even that minor problem, but there is not such a solution, so I am probably going to use Quality 50).


I agree, provided that the lowpass cutoff is not too low (11 kHz or less).


WMA CBR 64k has a cutoff frequency around 12.5 kHz: I understand that you consider it high for *that* bitrate. By the way, I notice the artifacts especially of WMA CBR 48 kbps, which pretends to have a cutoff at 12 kHz.

Thanks for your help. You are saying something different from what many people say in these forums - they cannot accept cutoff frequencies below 15 kHz (but they must go with higher bitrates, of course).

Ipotesi

hmm.... Maybe many audiophiles or music listeners don't prefer wma as a lossy audio codec and even claim that they are bad in quality compared to other lossy audio format.....
I was one of them before.... haha....

But the wma encoder sure has been better by the release of wma 9.2......
produces better audio quality than the wma 9.1, and... smaller filesize at same quality setting.....
I've tried encoding some songs of jazz and metal using the wma 9.2 encoder provided in the jet audio 7....
well, just for fun.....
at first I tried the 64kbps cbr....
the jazz song sounds ok, but not acceptable to me and the metal song 'shreded' my ear......

considering the fact that wma is better than mp3 at bitrates below 96kbps,
I made a second try to encode the same songs into wma vbr quality 50.....
which has the range of 50 to 95 kbps....
I'm quite impressed, shocked with the results.....
It should not make sense but from my ears it seems that both jazz and metal songs sounds good that
they are almost indistiguishable with the same song encoded with mp3 (vbr 160 kbps average).
And as an audiophile, my ears have been exposed to the perfect-lossy sound of mp3 at 320kbps cbr with my walkman for 2 years....
low-quality wma would not be my choice but the vbr quality 50 of wma 9.2 really impressed me....
I think that's the best setting for wma 9.2,
considering the sound quality and the size.
wma 9.2 should be a good news for portable audio player users.
since...
-no portable audio player support wma pro, which is better than standard wma
-it's kinda 'economic' for a player capacity. having 930MB of capacity enables a total of about 380 songs to be stored
with setting of vbr 50. the sound is good too.....
-less/no artifacts or distortion due to high frequency sound - compared to previous version of wma 9.1


sometimes we need to venture into something new......
mp3 is one of the best lossy audio encoder, but not THE ONLY.....
so if anyone thinks of wma, don't hesitate to try it....
haha...
well, just sharing my opinion....