Best mode should be -z3, not -7 -p -t2
You're obviously right, my mistake. When speed is not an issue '-z3' is a totally different story. Still a little slower, better compression, stable performance level.
And it shows no wonder:
MP4ALS RM17 -7 -n2560 -o32 64,19%
LA v0.4b high 65,99%
OptimFrog v4.600exp ultranew experimental 66,16%
Monkey v4.01 Insane 66,34%
MP4ALS RM17 -z3 -p -t2 -b 66,42%
and no shame:
MP4ALS RM17 -z3 -p -t2 -b 53,69% 43,38%
OptimFrog v4.600exp fast 55,05% 45,42%
Yalac v0.11 fast 55,80% 49,36%
Monkey v4.01 fast 58,01% 49,48%
WavPack v44a3 -hh 60,30% 49,83%
MP4ALS RM17 -7 -p -t2 60,68% 50,09%
That said, in my opinion things do not change that much. It still looks a little odd to see a '-o32' mode over 2% better than a '-z3' mode on the first sample and an almost 7% gap between '-z3' and '-7' on the other ones.
...would it be possible for me to get this sample to see if I can find anything special about it?
Of course! I hope you got my PM. Though currently I'm not done with it, on the same sample the second best encoder is... RkAu!