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Topic: Question about -q0 (Read 3002 times) previous topic - next topic
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Question about -q0

Hi,

Is there anything currently being used in conjunction with -q0.  I thought I read something somewhere about a newer noise shaping routine put on either -q1 or -q0.  I want to experiment with -q0, but don't want any extra crap messing with the results.  Also, does adding -Z to a commandline without -nspsytune still active the regular noise shaping routine?  Just double checking.  This question is in regards to version 3.91.

thanks,
mp3fan

Question about -q0

Reply #1 –
Quote
Originally posted by mp3fan
Hi,

Is there anything currently being used in conjunction with -q0.  I thought I read something somewhere about a newer noise shaping routine put on either -q1 or -q0.
Yes, -q0 activates new experimental and very slow noise shaping. It's different than pre-3.90 -q0. I once tested it with high bitrate nspsytune and it wasn't good. Could be better at low bitrate cbr gpsycho though, but it's experimental..

Quote
Also, does adding -Z to a commandline without -nspsytune still active the regular noise shaping routine?  Just double checking.  This question is in regards to version 3.91.
If you use -Z without nspsytune it will use "noise shaping type 2" which means there will be more use of scalefac_scale than without -Z (noise shaping type 1).
http://www.hydrogenaudio.org/forums/showth...d=5608#post5608

I think using "noise shaping type 2" with GPSYCHO is not such a good idea.. and it leads to problems also with nspsytune with clips like fatboy. Since nspsytune uses "noise shaping type 2" by default, using -Z will make it switch to "noise shaping type 1" which can improve especially fatboy etc. type of signals.
Juha Laaksonheimo

Question about -q0

Reply #2 –
Quote
Originally posted by mp3fan
Is there anything currently being used in conjunction with -q0.  I thought I read something somewhere about a newer noise shaping routine put on either -q1 or -q0.


Yes, there is a new noise shaping routine in use from Takehiro (I think it starts at -q0 but I haven't looked at the source in awhile).

However, -q0 is not designed to raise quality at all over noise shaping 2 or 1.  Instead, it's designed to save even more bits than noise shaping 2, which means it will also allow for even more error.  This, and its 40-400% slower, often only saving 2-5kbps.  I've experimented with it some, but I just can't see how it's advantagous given those circumstances.

Quote
I want to experiment with -q0, but don't want any extra crap messing with the results.  Also, does adding -Z to a commandline without -nspsytune still active the regular noise shaping routine?


-Z toggles noise shaping 1 or 2 depending on what it is currently set to.

With nspsytune, noise shaping 2 is on, so -Z turns it to 1
Without nspsytune noise shaping 1 is, on so -Z turns it to 2

However, the new noise shaping mode actually enables noise shaping 2 and then builds upon that, making it even more aggressive, if I remember correctly.

Question about -q0

Reply #3 –
Quote
Originally posted by JohnV
I think using "noise shaping type 2" with GPSYCHO is not such a good idea.. and it leads to problems also with nspsytune with clips like fatboy. Since nspsytune uses "noise shaping type 2" by default, using -Z will make it switch to "noise shaping type 1" which can improve especially fatboy etc. type of signals.


It's also worth noting, for those that may not know, that with nspsytune and type 2, if my adaptive techniques are used (--alt-preset), then there are no longer issues on clips like fatboy.  Without these specific tunings though, you are correct.