[FieldTrip] problem with reading .edf+ files

[Schönherr, Margit]

Hello Robert,

thank you for the easy solution, it works with cfg.continuous='yes'.

Margit


________________________________________
Von: fieldtrip-bounces at science.ru.nl [fieldtrip-bounces at science.ru.nl] im Auftrag von Robert Oostenveld [r.oostenveld at donders.ru.nl]
Gesendet: Donnerstag, 6. Dezember 2012 22:44
An: FieldTrip discussion list
Betreff: Re: [FieldTrip] problem with reading .edf+ files

Hi Margit

The EDF and derived formats (EDF+, BDF, GDF) write the data as short segments in the file. Usually the subsequent segments can be glued together to form a continuous representation, but that is not guaranteed by the fileformat.

I cannot check at the moment, as I don' have an EDF file handy, but I would expect that if you specify cfg.continuous='yes' to ft_preprocessing that it will be interpreted as a single continuous recording, rather than as an epoched recording.

best regards,
Robert


On 5 Dec 2012, at 17:07, Schönherr, Margit wrote:

> Hello,
>
> I want to analyze invasive EEG data and I have problems reading the data correctly. The data are continuous and I used BESA to convert them to .edf format. When I read them into matlab, however, the data are not continuous anymore, but segmented into very short trials. For example, a data set of 1 hour is split into 8229 trials of 0.43 s length. Even more confusing, the trial length differs across subjects.
>
> What is the difference between .edf and .edf+? BESA Research produces the latter, could this be the reason for the issue?
> I also tried to track down the place where the segmentation into trials is done, but I ended up at line 111 of read_edf.m (EDF.Dur = str2num(H1(245:252))  % 8 Byte  # duration of data record in sec).
>
> I would be very glad if someone could tell me, how to read the data correctly with fieldtrip. Thanks!
>
> Best,
> Margit
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip


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