[Eeglablist] Strange behavior in EEGLab BDF read/write functions ?

[Pierre Vigneron]

Hello the EEGLab community,

i'm using EEGLab 2023.0 and I need to correct triggers inside BDF files.

But I experience some strange behaviour when I load and save a BDF file 
without altering it : the triggers are NOT the same.

Here is a very minimal example, based on the test.bdf file provided by 
EEGLab.

------------------------------

clearvars
close all

% This script tests the EEGLab BDF Read/Write functions


f_in = '/opt/eeglab2023.0/sample_data/test_data/test.bdf';
f_out = './test_out.bdf';

eeglab nogui
eeg_in = pop_biosig(f_in);

pop_writeeeg(eeg_in, f_out, 'TYPE','BDF');
eeg_out = pop_biosig(f_out);

eeg_in.event(1)
eeg_out.event(1)

------------------------------

The first event in eeg_in is :

   struct with fields:

        type: 254
     latency: 257
     urevent: 1

While the first event in eeg_out is :

   struct with fields:

        type: 10170
     latency: 257
     urevent: 1

As you can see, the type has changed !

Have you some clue about what's happening here ?

Thanks a lot for any advice !

BR

Pierre

--
*Pierre Vigneron, PhD*
Ingénieur de Recherche mutualisé Modyco <https://urldefense.com/v3/__https://modyco.fr__;!!Mih3wA!BGU-G9NWLMEYbI3K5XH6QWCnx9eXOwGpBJzclriT5EYBGd-neER7Oe9HvmdgL3BQquhjtHxg4X8K1hrAzTgE96_rSSMfhbY$ > / EconomiX 
<https://urldefense.com/v3/__https://economix.fr__;!!Mih3wA!BGU-G9NWLMEYbI3K5XH6QWCnx9eXOwGpBJzclriT5EYBGd-neER7Oe9HvmdgL3BQquhjtHxg4X8K1hrAzTgE96_rRrVBeP4$ >
Université de Paris Nanterre