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Ogg RC3 and -q4 vs. -q5

Hi everyone and a happy new year 
I encoded some extreme metal tracks with Ogg RC3 with quality 4 and quality 5 and I was surprised that I really could not tell any difference! I'm thinking of encoding all my CDs with quality 4, but I'd like to know your opinion on these two quality settings in encoding terms, like lossless channel coupling (btw, what is this exactly and where can I find some info about all these terms?)

Thanks for your time,
Wizard


Ogg RC3 and -q4 vs. -q5

Reply #2
If I'm not wrong, q4 uses 8-phase stereo while lossless stereo is used from q5 onwards. It seems to be that 8-phase stereo is already very good while lossless stereo makes the bitrate go up quite a lot. 8-phase stereo really delivers quality for bitrate.

q = 4.9 would probably be the highest you can go with 8-phase stereo. Will be interesting to see how this compares with q = 5 (where there is a jump in bitrate). It if compares favourably, it might be a good idea to have a setting to force vorbis to use 8-phase for higher bitrates...

Check out Jon Ingram's plots of bitrates and quality levels here: http://www.maths.warwick.ac.uk/~jingram/ogg/group.png

Ogg RC3 and -q4 vs. -q5

Reply #3
Well, I tested more metal tracks and the results were:
-q4  -> 123kbps
-q4,9-> 127kbps
-q5  -> 157kbps

I think I'll stick with -q4,9 
BTW, shouldn't the RC3 ogg files say 20011231 for date and not 20011217?

Ogg RC3 and -q4 vs. -q5

Reply #4
Yes it should. If yours doesn't, you need to pick it up again.

john33
John
----------------------------------------------------------------
My compiles and utilities are at http://www.rarewares.org/

Ogg RC3 and -q4 vs. -q5

Reply #5
Quote
q = 4.9 would probably be the highest you can go with 8-phase stereo.

<pedantic>
You can insert some more 9s in there...
q = 4.9999999
</pedantic>

Ogg RC3 and -q4 vs. -q5

Reply #6
Quote
Originally posted by john33
Yes it should. If yours doesn't, you need to pick it up again.

john33


My mistake, didn't express it right  I meant the .ogg files that the official OggEnc1.0RC3 or OggDrop1.0RC3 make. Ogginfo reports that "vendor=Xiphophorus libVorbis I 20011217". If I use BQOggDrop1.0RC3, Ogginfo reports 20011231. This could be the cause of wrong assumptions about the encoder used for the .ogg files. Maybe it should have the "RC3" string, too

Ogg RC3 and -q4 vs. -q5

Reply #7
Quote
Originally posted by tangent
If I'm not wrong, q4 uses 8-phase stereo while lossless stereo is used from q5 onwards. It seems to be that 8-phase stereo is already very good while lossless stereo makes the bitrate go up quite a lot. 8-phase stereo really delivers quality for bitrate.

q = 4.9 would probably be the highest you can go with 8-phase stereo. Will be interesting to see how this compares with q = 5 (where there is a jump in bitrate). It if compares favourably, it might be a good idea to have a setting to force vorbis to use 8-phase for higher bitrates...

Check out Jon Ingram's plots of bitrates and quality levels here: http://www.maths.warwick.ac.uk/~jingram/ogg/group.png


I need to update the stereo doc to reflect exact usage in rc3.  There's no phase stereo at all in rc3, where stereo is used, it's all point stereo.  This allowed a number of design simplifications.  The horrors of designing a general use codec and all that.

from -q4 up to -q 5-minus-epsilon, libvorbis uses 6dB point stereo at >10kHz.  from -q5 and above, the coupling is lossless.

Monty

Ogg RC3 and -q4 vs. -q5

Reply #8
Hmm.. I've been doing all my encoding with 4.9
Arghh.. now I have to delete them all and change to 4.99999999999999999999

sigh

Ogg RC3 and -q4 vs. -q5

Reply #9
Quote
Originally posted by xiphmont


I need to update the stereo doc to reflect exact usage in rc3.  There's no phase stereo at all in rc3, where stereo is used, it's all point stereo.  This allowed a number of design simplifications.  The horrors of designing a general use codec and all that.

from -q4 up to -q 5-minus-epsilon, libvorbis uses 6dB point stereo at >10kHz.  from -q5 and above, the coupling is lossless.


Thanks for clarifying that Monty.

Ogg RC3 and -q4 vs. -q5

Reply #10
Quote
BTW, shouldn't the RC3 ogg files say 20011231 for date and not 20011217?


I'm getting that too and I'm encoding with the official RC3 oggenc...

Ogg RC3 and -q4 vs. -q5

Reply #11
I tried the new RC3 that sounds cool.

The only bad thing is the way oggdrop manage the bitrates: almost incomprensible.

I hope to see oggdrop' settings like the ones used by dbpoweramp

http://www.dbpoweramp.com

Ogg RC3 and -q4 vs. -q5

Reply #12
Monty said on the mailing list that VBR modes (=quality modes) give better quality then ABR mode, so just find your best setting and encode right away.

Quote
Well, we need to find some subtle way to dicourage people from using
ABR.  The masses will immediately latch onto 'bitrate' settings
because that's what they're used to in mp3, completely ignoring the
fact that quality settings will *always* produce a higher quality file
for the same given size.  Just putting it in the manual isn't enough,
most folks couldn't care less about documentation....


Monty

Ogg RC3 and -q4 vs. -q5

Reply #13
Quote
Originally posted by PatchWorKs
I tried the new RC3 that sounds cool.

The only bad thing is the way oggdrop manage the bitrates: almost incomprensible.

I hope to see oggeng settings like the ones used by dbpoweramp

http://www.dbpoweramp.com


You can get BQoggdrop for a more clear bitrate management.

It's at my site (Bottom of message)

Regards;

Roberto.

Ogg RC3 and -q4 vs. -q5

Reply #14
I already have it... a bit clearer.
Where can i define MY OWN bitrate ?
Where can i define MY OWN min and max bitrate ?

Dbpoweramp OGG plugin still rules...

Ogg RC3 and -q4 vs. -q5

Reply #15
Hey, it's CLEARER, not packed with features

Ogg RC3 and -q4 vs. -q5

Reply #16
please tell me why one should use MIN and MAX Bitrate. The only thing that counts is quality  Experiment a bit with the settings and you're done. Better then limiting the encoder's possibilities...

Ogg RC3 and -q4 vs. -q5

Reply #17
MODatic

I also checked the date on the official RC3 oggenc regarding the libraries. It certainly does say 20011217.

This is not a problem, it is using the correct RC3 libraries, it is just that the official compile was produced about 6 hours before the file 'info.c', the one that contains the version numbers, was updated in the CVS!!!!

john33
John
----------------------------------------------------------------
My compiles and utilities are at http://www.rarewares.org/

Ogg RC3 and -q4 vs. -q5

Reply #18
Quote
Originally posted by xiphmont


I need to update the stereo doc to reflect exact usage in rc3.  There's no phase stereo at all in rc3, where stereo is used, it's all point stereo.  This allowed a number of design simplifications.  The horrors of designing a general use codec and all that.

from -q4 up to -q 5-minus-epsilon, libvorbis uses 6dB point stereo at >10kHz.  from -q5 and above, the coupling is lossless.

Monty


will the Stereo modes for 4 - 4,99 be subject to change until the final release?
What tweaks (if any)are planned in the psy model for that quality range until final release? I heard that RC4 will bring improvements for low bitrates...

So generally, I dunno if I should wait with vorbis a little longer before using it for my mid-quality audio releases.

greetings and thx

 
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