I just tried to apply a lowpassfilter of 70 Hz using the bandpass filter function (run > load/save processing pipeline > load > bandpass; 0-70 Hz). After a long time of waiting I got this error in my Matlab command window:
EDF> ERROR: File is truncated (0 time samples were read instead of 56). Padding with zeros...
In my raw EEG file, I now see two small segments created (one at the beginning of the file, one at the end) called ‘transient_bandpass’. Does this mean the lowpassfilter succeeded for every part accept the beginning and the end, or only worked for the beginning and the end?
In short: Is my data now actually low pass filtered or not?
Thanks!
p.s. I previously applied the same steps for another patient file and there I did not get an Error.
The event transient_bandass is inherent to the filtering process, it can be thought as the time the filter "settles down", as it starts filtering without data. This event is in red as it is considered bad. For FIR filters the full transient last N/2 with N being the order of the filter. In Brainstorm the transient event is set to 99% of the energy.
It is. This can be verified by computing the PSD of the data.
The error is not for the filter, but reading the EDF file, it seems there is some issue with it, or the EDF reader. Could you share a file that gives you the error to understand what is going on?
