Issue with edfread - "The input, '2021-06-0​4T15:42:31​.188466-04​:00', did not match any of the valid values."

Hi,

I'm trying to read an EDF file from an Emotiv EPOC, but I keep getting the same error when I try to use edfread. I have tried renaming the edf file so it didn't have the date in the title, but that didn't help (so I had the name as 'Event_Marker_Try_4_EPOCX.edf'). I still got this same error. I need to use the EDF format because that gives an accurate timestamp (vs the CSV file). Does anyone know how I can fix this issue?

Thank You!

[Yongjian Feng]

The time format does look good. Try to validate your edf file first.

[Christina Diersing]

@Yongjian Feng How can I do that? (I've never worked with EDF files before)

Answer 1

[Walter Roberson]

Positions 193 to 236 of the file must be 'EDF+C' or 'EDF+D' or blank, but instead it is that particular time.

The program does not believe that your file is a valid EDF or EDF+ file.

[Christina Diersing]

How can I fix this? (It's my first time working with EDF files)

[Walter Roberson]

Can you zip the edf file and attach it for us to examine?

[Walter Roberson]

https://emotiv.gitbook.io/emotivpro/exported_data_files/edf_files

The file format described has nothing to do with European Data Format

[Walter Roberson]

https://github.com/akshaybabloo/Emotiv-Matlab

https://github.com/ibrahimjad/emotiv-matlab

https://emotiv.gitbook.io/emotivpro/notes_on_the_data/code-examples

https://nilosarraf.com/2021/04/11/tips-on-eeg-data-processing-using-eeglab-on-matlab-with-emotiv-epoc-neuroheadset/

[Christina Diersing]

@Walter Roberson Sure! Here is the file.

I just saw your other comments, so I'll check out the video. Thank you!

[Christina Diersing]

@Walter Roberson I am using the Pro 2 software, which, according to EMOTIV, is European Data Format:

https://emotiv.gitbook.io/emotivpro-v2-0/exported-data-files/edf-files (if you click on the EDF specifications link, it takes you here: https://www.edfplus.info/specs/edf.html ).

I have looked at the first 3 links on your last comment. The first two use a different version of Emotiv Pro and the new version doesn't seem to have the same capabilities. The third link I've read through and my only problem is with the timestamp. The csv file has several samples per timestamp when imported to Matlab, and Matlab won't accept that. Is there a way I can change the timestamp values in the csv file to float, instead of excel rounding it to the nearest whole number? Or do you think I could make a new column so Relative_Timestamp=Timestamp+(EEG.counter/1000)-(the first timestamp)?

I've attached a zip of the csv file I have. So, in the case of that file for example, Relative_Timestamp=Timestamp+(EEG.counter/1000)-1622835751?

I really appreciate your help with this. I've spent the better part of a month trying, unsuccessfully, to get this data into Matlab but none of my professors know how to get Emotiv data into Matlab. I finally feel like I'm getting somewhere so thank you so much!

[Walter Roberson]

I do not see any problem importing the csv.

t = readtable('Event Marker Try 4_EPOCX_126368_2021.06.04T15.42.31.04.00.md.csv');
t.dt = datetime(t.Timestamp, 'convertfrom', 'posixtime');

The Timestamp column is imported as floating point, and the times show up as about 04-Jun-2021 19:42:31 in my timezone.

[Walter Roberson]

The edf file is not compliant with EDF or EDF+ . In particular, the "reserved" field must be:

https://edfrw.readthedocs.io/en/latest/specifications.html

‘reserved’: empty for EDF; ‘EDF+C’ for continuous recording; ‘EDF+D’ if the recording is interrupted.

However, instead it is a time specification.

[Christina Diersing]

Okay, I finally have the correct timestamps and data imported. Thank you so much for your help!

Answer 2

[Christina Diersing]

So, I've attached a zip file with my code and the csv file I used. I had to copy the timestamp and sensor data into a new excel document to make it so Matlab could import it. In excel, I selected all of the numbers, right clicked, selected 'Format Cells', under 'category' I selected 'number' and I changed the decimal places to '6'. (I'm not sure if that affected the data being imported to Matlab or not, but I prefer seeing the number with decimal places).

Here is a copy of the code if you don't want to download the zip file:

%%Importing_data_from_csv_to_Matlab
%add paths and change current directory to the correct folders
addpath 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings\Event Marker Try 4'
cd 'C:\Users\chris\Documents\College\Sixth Year\DAGSI\Data\EMOTIV Recordings'
format long; %this stops Matlab from rounding the timestamps and data
T=readtable('Try 4.csv'); %reads the csv file into Matlab and assigns the data to variable/table T
%Lines 8-16 Assign variables to the EEG data for each electrode
timestamp=T.Timestamp-1622835751.18846; %this makes timestamp 0 at the start of the recording
T.Timestamp=T.Timestamp-1622835751.18846; %This changes the official Timestamp column so it is 0 at the start of the recording 
AF3=T.EEG_AF3; F7=T.EEG_F7;
F3=T.EEG_F3; FC5=T.EEG_FC5;
T7=T.EEG_T7; P7=T.EEG_P7;
O1=T.EEG_O1; O2=T.EEG_O2;
P8=T.EEG_P8; T8=T.EEG_T8;
FC6=T.EEG_FC6; F4=T.EEG_F4;
F8=T.EEG_F8; AF4=T.EEG_AF4;
%Line 18 just shows that it correctly imported the data
T5=head(T, 5) %shows first 5 rows of table T

% Plot all electrode readings on the same plot (vs timestamp)
plot(timestamp, AF3);
hold on;
plot(timestamp, F7);
plot(timestamp, F3); plot(timestamp, FC5);
plot(timestamp, T7); plot(timestamp, P7);
plot(timestamp, O1); plot(timestamp, O2);
plot(timestamp, P8); plot(timestamp, T8);
plot(timestamp, FC6); plot(timestamp, F4);
plot(timestamp, F8); plot(timestamp, AF4);
%Label plot
legend('AF3', 'F7', 'F3', 'FC5', 'T7', 'P7', 'O1', 'O2', 'P8', 'T8', 'FC6', 'F4', 'F8', 'AF4');
title('Try 4 EEG Test');
xlabel('Timestamp (s)');
ylabel('EEG Value (uV)');

I hope this helps!

[Walter Roberson]

T = readtable('Try 4.csv');
T.dt = datetime(T.Timestamp,'convertfrom', 'posixtime','format', 'dd-MMM-yyyy HH:mm:ss.SSSSSS');
timestamp = T.dt - T.dt(1);
AF3=T.EEG_AF3; F7=T.EEG_F7;
F3=T.EEG_F3; FC5=T.EEG_FC5;
T7=T.EEG_T7; P7=T.EEG_P7;
O1=T.EEG_O1; O2=T.EEG_O2;
P8=T.EEG_P8; T8=T.EEG_T8;
FC6=T.EEG_FC6; F4=T.EEG_F4;
F8=T.EEG_F8; AF4=T.EEG_AF4;
plot(timetamp, [AF3, F7, F3, FC5, T7, P7, O1, O2, P8, T8, FC6, F4, F8, AF4]);
legend({'AF3', 'F7', 'F3', 'FC5', 'T7', 'P7', 'O1', 'O2', 'P8', 'T8', 'FC6', 'F4', 'F8', 'AF4'});
xlabel('Timestamp (s)');
ylabel('EEG Value (uV)');