Originally any2matlab converted the file format string (format ID and
subformat specifications) to lower case. This appears unnecessary and in
fact results in failing code, if for example the modifier
'estimateNframes' has to be passed with 'mseed'. There currently is no
obvious reason, why case conversion should be done in any2matlab. If it
should turn out that existing matlab code relies on any2matlab doing
this conversion, the matlab code has to be fixed, doing the conversion
in matlab before calling any2matlab.