[MINC-users] mincconvert -compress broken?

[Alex Zijdenbos]

Hi Claude,

Thanks! And yes, it turns out that I needed 'mincconvert -compress 4 -2'.

I had started with 'mincconvert -2 in.mnc out.mnc', with the
environment vars below, thinking that it would simply (internally)
compress my minc2 file. But I was told that my input file is already
minc2, so I removed the -2; then added -compress. That caused
mincconvert to generate a minc1 file, for which -compress doesn't
work.

 I think the simple solution would be to add a check in minccompress
that warns the user in case -compress was specified, but the output
file is minc1?

-- A

> Interesting...
>
> Do you have environment variables like these that could interfere?
>
> MINC_FORCE_V2=1
> MINC_COMPRESS=4
>
> Try: "file test_compressed.mnc". Is it minc1 or minc2?
>
> Do you need -compress 4 -2 ?
>
> Usually, the best test is to gzip the file. What is the size of test.mnc.gz?
> minc2 achieves essentially the same compression ratio as gzip (for the data
> part).
>
> You can also forward me your test.mnc if you want me to have a look at it.
> I'm the one to blame for the current blocking strategy for compression in
> minc2.
>
> Claude
>
>> I just ran into this:
>>
>> $ mincconvert -compress 4 test.mnc test_compressed.mnc
>> $ du -hs test*mnc
>> 23M     test_compressed.mnc
>> 15M     test.mnc
>>
>> That wasn't exactly the desired effect :)
>>
>> $ mincconvert -version
>> program: 2.1.00
>> libminc: 2.1.00
>> netcdf : 3.6.1 of Dec 22 2010 16:29:38 $
>> HDF5   : 1.8.5
>>
>> However, I get the exact same thing with a 2.0.18 version of
>> mincconvert; and no matter what argument (1-9) I provide to the
>> -compress option. So from what I can see, 'mincconvert -compress' does
>> nothing at all?
>>
>> -- Alex
>> _______________________________________________
>> MINC-users at bic.mni.mcgill.ca
>> http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
>>
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