lossyWAV Development
Reply #207 – 2007-09-25 07:55:32
For a promising way to continue testing (and keeping in mind that v0.2.0 -s yielded excellent results) it is important to know what we're testing. Can you please confirm or correct the following statements: a) just to make sure the basis: v0.2.2 -skew 9.0 (no other options) yields exactly the same results as v0.2.0 -s (no other options). Especially the v0.2.2 noise threshold default is exactly equal to that of v0.2.0? b) to try out the fft_length dependent bin averaging the following options are useful to test v0.2.2 -vsfl -skew x -nts y with x<=9.0 (for instance x=6.0) and y>=-3.0 (for instance y=-1.0). And as 2Bdecided said -nfc should be used for abxing to make sure no loudness difference is abxed. What exactly does the weighted spreading function option -wsf do? a) Should be almost exactly the same (although the skew in v0.2.0 was 9.0309, i.e. 1.5 x 20 x log(2)). b) Sounds good. -nfc is alright - unless the sample clips under bit-reduction. There is no clipping prevention at all when -nfc is used. -wsf creates spreading functions as follows: [1]; [2/3,1/3]; [3/6,2/6,1/6]; [4/10,3/10,2/10,1/10]; [5/15,4/15,3/15,2/15,1/15]; [6/21,5/21,4/21,3/21,2/21,1/21]; rather than [1]; [1/2,1/2]; [1/3,1/3,1/3]; [1/4,1/4,1/4,1/4] etc. The weighted spreading function tends to 75% below midlength, 25% above midlength as length tends to infinity. I am developing with a variant of this which tends to 7/12 below midlength, 5/12 above midlength. @2Bdecided: I noticed on running the Matlab script with the same parameters several times in a row on the same input file that the average bits_to_remove value changes....? I can't pin down the cause, does it do that for you?