[Eeglablist] memory problems when reading in 128 channels Biosemi data

[Brian Roach]

Hi All,

I would not use the matlab export in Brain Vision Analyzer.  A generic data 
export will create smaller files that can be more reliably read into EEGlab 
via the pop_loadbv.m function.  Another (cheaper) alternative would be to 
use the biosemi "file cropper" tool to cut the file into smaller chunks, 
read each into EEGlab.  This is basically what Jim was saying in his 
earlier reply, but it's good to know that the tools are freely available 
for download (http://www.biosemi.com/download.htm).  There is a decimater 
there as well, if you do not need as high a sampling rate then you might be 
able to down-sample and work with your data.

Brian
At 03:21 PM 5/22/2007, Jaskirat Wild wrote:
>Hi Miriam-
>
>We encountered the same problem when importing .bdf's generated by 
>Biosemi. The files are quite large because Biosemi has a uniquely large 
>dynamic range, allowing sampling of ultra-low frequencies. If these 
>frequencies are not of interest to the researcher, then one workaround is 
>to high-pass filter the data above .1 or 1 Hz. This can be accomplished 
>using the free software application LabVIEW (available on Biosemi's 
>website), which will filter the data and convert the .bdf files to much 
>smaller .edf files.
>
>We ultimately ended up using Brain Vision Analyzer to filter the data and 
>export only the primary channels of interest in .edf format. Note that the 
>Matlab export add-in from Brain Vision doesn't always work.
>Good luck!
>
>-Jaskirat
>
> >>> "Miriam Gade" <gade at sissa.it> 5/22/2007 12:27 AM >>>
>Hi all,
>
>we recently bought a Biosemi EEG System and are now trying to analyse a 
>first oddball experiment  recorded with 128 channels. However, EEGLAB 
>continously reports memory failures when we try to read the data in, even 
>though the task manager under windows shows 500 MB of free memory. Has 
>anybody of you encountered the same problem? Do you know how to circumvent 
>it? thanks for any answers and greetings from italy miriam
>
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