[Eeglablist] Issue for importing GDF file - empty EEG data structure

[Alois Schlögl]

Dear all,


the issue was indeed a bug in the biosig4matlab implementation of read 
GDF 1.x file formats. The issue is addressed by this commit [1].


The bug did not affect GDF 2.x data files, or when using
libbiosig/mexSLOAD to read GDF 1.x data files.
The bug was an artifact from the times when fread(...) of Matlab/Octave 
did not support reading 64bit integers, and the DigMax, DigMin values 
exceeded 2^31 (about 2e9).

In order to fix the bug, I recommend downloading sopen.m from [2] and 
replace your copy of sopen.m

It will be included also in the next release.


Best,
   Alois





[1] 
https://urldefense.com/v3/__https://sourceforge.net/p/biosig/code/ci/03a01e125cbac0a3c9cb0e34d891ed5b7b769d31/__;!!Mih3wA!CvbWb032kZfg8tUyEDlDNolLB-kZDAB_E1sopWT500nIfgFe3MKu4ijGkC6GdqMhagUgJSp24DLGIB_suf0FqvKrU4KF2v4O$ 

[2] 
https://urldefense.com/v3/__https://sourceforge.net/p/biosig/code/ci/03a01e125cbac0a3c9cb0e34d891ed5b7b769d31/tree/biosig4matlab/t200_FileAccess/sopen.m?format=raw__;!!Mih3wA!CvbWb032kZfg8tUyEDlDNolLB-kZDAB_E1sopWT500nIfgFe3MKu4ijGkC6GdqMhagUgJSp24DLGIB_suf0FqvKrUwIV_1VP$ 



Am 10/17/23 um 18:51 schrieb Arnaud Delorme via eeglablist:
> Dear Emeline,
> 
> Would you mind to create an issue and upload your data file at
> 
> https://urldefense.com/v3/__https://github.com/sccn/eeglab/issues__;!!Mih3wA!HHXbtTpc1iV64N79Og5S2_6vSo83RkBtVWHtT-d29ylCgPr31szFNI4a2bBRKXhcSEQ8VC8g7k3KK1Y9JiRy9PU8$
> 
> We will see with Alois (developer of BIOSIG - EEGLAB uses BIOSIG to import GDF files) what the problem is. My intuition is that OpenVibe does not save GDF compliant files. Alois designed GDF
> 
> https://urldefense.com/v3/__https://arxiv.org/abs/cs/0608052__;!!Mih3wA!HHXbtTpc1iV64N79Og5S2_6vSo83RkBtVWHtT-d29ylCgPr31szFNI4a2bBRKXhcSEQ8VC8g7k3KK1Y9JsuTfpaX$
> 
> So you can trust that BIOSIG (also developed by Alois) imports GDF properly.
> 
> Cheers,
> 
> Arno
> 
>> On Oct 17, 2023, at 2:52 AM, Emeline Pierrieau via eeglablist <eeglablist at sccn.ucsd.edu> wrote:
>>
>>
>>
>> Hi,
>>
>>
>>
>> I am trying to import a GDF file from a 128 electrode BioSemi system (data are recorded in GDF format because they are saved in OpenVibe). I use the BIOSIG toolbox, and only add information about the number of the reference channel in the pop_biosig window. I don’t receive any error message or warning in Matlab command window but the EEG data structure of the file is completely empty.
>>
>> Note that the GDF file isn’t empty, it shows normal oscillatory activity when readed in OpenVibe. Note also that I already imported GDF files from OpenVibe in EEGLAB in a previous study using an ANTNeuro system and it worked fine. What can I do to properly import the GDF file this time?
>>
>>
>>
>> Best regards,
>>
>>
>>
>> Emeline
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