[Eeglablist] EEGLAB BDF script

[Bradley Voytek]

I sent this to Arno, and he thought I should just send it on to the whole list.

I've seen a number of messages on here, and have spoken with several
folks here at Berkeley, about memory issues when importing BioSemi BDF
files. I'm sure you guys already know this, but the issues stem from
the fact that multiple versions of the dataset are created. If the
original dataset is > ~400MB or so, then the import fails.

The BioSemi system can indeed downsample data for you, however even at
a modest 256Hz sampling rate, a long recording session can easily go
over this 400 MB limit.

I've written a pretty dirty, but functioning script that takes all the
raw BDF files in the pwd, imports them in segments, saves the
segments, reloads them (weird I know, but it avoids some memory
issues), merges them (within the script, to avoid the fact that
pop_mergeset creates a copy of the dataset as well), saves the merged
version, and removes the temporary files.

This lets you import BDF files as big as at least 1GB I'd say, though
in theory if you make the segments small enough, you could import
files close to 2GB (MatLab's memory limit on non-Linux machines).

There are probably some things at the bottom of the script other
people would want to change: I have this script look up channel
locations on the Mac I'm using, and I also have it create a standard
naming structure for the files. But those are minor tweaks.

Hopefully someone on the list could find this useful.

Cheers!

::brad

--

Bradley Voytek
PhD Candidate: Neuroscience
Helen Wills Neuroscience Institute
University of California, Berkeley
132 Barker Hall
Berkeley, CA 94720-3190

btvoytek at berkeley.edu
213.840.4560 (cell)
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