We are doing pre-processing for our continuous MEG data by applying band-stop filter for the frequencies (50,100,150,200,250,300) and it was working well
for your information , we updated brainstorm and we have about 18 GB free on our C/ disk space.
While we were running band-stop filter, an error appeared that "only one frequency band is allowed "!
Indeed, we modified the implementation of the bandstop filter recently.
This implementation (and the previous one) were generating very poor band-stop filters when trying to remove multiple frequency bands with a single filter.
We now enforce the computation of separate band-stop filters for separate frequencies.
Rewrite your script so that it calls this process multiple times instead.
Note that for removing 50Hz contaminations, notch filters are usually better indicated. And the design of notch filters that remove simultaneously multiple frequencies is possible.
To help you design filters adapted to your data, we added a representation of the filter's response in time and frequency in all the frequency filters.
I will follow your suggestion, Francois.. Thank you for your fast reply.