Hmm... I've been doing my own tests of WavPack lossless using the 46 samples from rjamorim's listening tests. (183MB).
They *do not* closely correspond to the results that echo got - the ones which made me so excited a little while ago, but it still confirms that the answer to my original question is yes. The extra (-x) modes are more effective the faster the encoding setting.
Type Bytes Size % Change EncTime X Incr*
WAV 192,156,428 100.00% - - -
wv.f 116,620,743 60.69% -39.31% 33 -
wv.fx1 116,247,737 60.50% -0.19% 36 10%
wv.fx2 116,151,681 60.45% -0.05% 40 22%
wv.fx3 116,151,681 60.45% 0.00% 41 25%
wv.fx4 114,715,073 59.70% -0.75% 85 160%
wv.fx5 114,486,325 59.58% -0.12% 112 240%
wv.fx6 114,480,801 59.58% -0.00% 136 316%
wv.norm 113,662,299 59.15% -0.43% 29 -
wv.x1 113,393,555 59.01% -0.14% 40 38%
wv.x2 113,315,235 58.97% -0.04% 63 116%
wv.x3 113,089,013 58.85% -0.12% 108 271%
wv.x4 112,044,993 58.31% -0.54% 262 803%
wv.x5 111,973,775 58.27% -0.04% 398 1275%
wv.x6 111,891,125 58.23% -0.04% 839 2794%
wv.h 111,071,996 57.80% -0.43% 32 -
wv.hx1 110,920,564 57.72% -0.08% 80 150%
wv.hx2 110,836,849 57.68% -0.04% 141 339%
wv.hx3 110,562,922 57.54% -0.14% 633 1874%
wv.hx4 110,490,641 57.50% -0.04% 1142 3462%
wv.hx5 110,466,641 57.49% -0.01% 1614 4934%
wv.hx6 110,426,449 57.47% -0.02% 3422 10574%
EncTime is in seconds
*X Incr. is the increase in time it takes to encode in that -x mode over the regular non-x mode (normal/-f/-h)
100% = Double the Time
Some interesting things to note:
-fx6 is bigger than normal, and much bigger than -h.
-The difference between -f and -fx6 is about 2.0 MB / 1.1%
-The difference between normal and -x6 is about 1.7 MB / 0.9%
-The difference between -h and -hx6 is about 0.6 MB / 0.3%
The f-fx6,normal-x6,h-hx6 sequence produces filesizes that consistently get progressively smaller. As bryant said, with the x setting, the most significant changes always occur on -x4, except that -hx3 is slightly more significant than -hx4, and is a great measure faster, hence the default being set to x3 for -h mode.
-The difference between the biggest (-f) and smallest (-hx6) is about 6 MB, or 3.2%.
-fx2 and fx3 produced the exact same file sizes. Is this a trivial bug, maybe?
Edit:
Added the relevant times to the table above.