I was busy finishing the testing I was doing when I stumbled across something rather interesting...
When using so many apodizations, it seems the -e switch (exhaustive modelling) becomes less usefull. See this data
---- Compression setting ---- , Compr., Encsp, Decsp
-8 -A tukey(0.5) -A partial_tukey(2) -A punchout_tukey(3) , 56.450, 13.9 , 376.7
-8 -A tukey(0.5) -A partial_tukey(2) -A punchout_tukey(3) --no-exhaustive-model-search, 56.511, 64.0 , 379.9
-8 , 56.690, 60.1 , 379.0
-8 --no-exhaustive-model-search , 56.850, 169.5, 377.5
As you can see, with only the default apodization, the compression gain for using -e is 0.3% at the cost of reducing the encoding speed to 1/3th. However, when using six apodization functions, the gain is only 0.1% at the cost of reducing the encoding speed to 1/5th. So gain decreases while effort increases.
So, I've just sent a mail to the flac-dev list proposing to drop the use of the -e options for compression level -7 and -8 and instead using more apodization functions. You can see the difference here: http://www.audiograaf.nl/misc_stuff/settin...sualisation.pdf If this change is accepted, FLAC will be both faster and better compressing...