Change default export format to compressed hdf5

[k-dominik]

most ilastik outputs compress very well - compressed hdf5 should be made the default format.
Furthermore the default format can now be customized in the config.

accompanying volumina request to change the default order: ilastik/volumina#313

CC: @oanegros (#2796 (comment))

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (e813293) 55.75% compared to head (c3e9dfa) 55.77%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2812      +/-   ##
==========================================
+ Coverage   55.75%   55.77%   +0.02%     
==========================================
  Files         530      530              
  Lines       62173    62173              
  Branches     8498     8498              
==========================================
+ Hits        34663    34679      +16     
+ Misses      25764    25751      -13     
+ Partials     1746     1743       -3     

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[k-dominik]

this change has @akreshuk's blessing (pending me checking whether our compressed data would open in MoBiE and our plugin)

[btbest]

I agree it's a sensible change, and looks fine on my system 👍 25%-ish file size reduction even on a tiny test image.

[k-dominik]

The size reduction can be quite pronounced, depending on the data. My ballpark was usually that predictions will be half the size of their uncompressed counterparts.

It might be worth mentioning that this comes at a cost, too. I checked loading a random image into RAM completely, and the compressed version would take roughly 25% longer to load.

In the meantime I confirmed that

• our Fiji plugin
• the default fiji h5 reader
• MoBiE
  can read the compressed files.