EDF files

[rob-luke]

Hi Sam,
Are you interested in extending this package to EDF files? I have taken an initial step in my fork, but if you think its outside the scope then Ill move it somewhere else.

[sam81]

Hi Rob,
given that EDF and BDF are similar formats from one point of view it makes sense to have a single module that deals with both (may be easier to maintain than two separate packages), however, there is the problem of naming, currently the module is named BDF.jl, and people looking for a module to read EDF files maybe won't look here. So, I don't know what's the best, I'm fine with either option, I'd suggest you go on with the one you think is best.

Eventually, I think it would be great to have a single package that can read different EEG data files like BioSig with a common API, so creating such a project could be a third option, but with just two file formats (BDF and EDF) maybe it's a bit early to do that.

[rob-luke]

I'd not seen BioSig before, thats a great idea.
Once read, keeping the data stored in 2D arrays is easy. I guess the difficulty is in choosing a format for events. Is there a standard for this?

[rob-luke]

And I'll keep developing EDF functionality under BDF.jl. Im sure a short search would bring them here.

[sam81]

I haven't used BioSig in a while, last time I used it I think it returned events in an event table similar to BDF.jl

[sam81]

@codles : do you still have the git branch for EDF support? I was thinking of contributing to it when I have some free time. Looking at the specs the original EDF (1992 spec: http://www.edfplus.info/specs/edf.html) seems really straightforward to implement. The EDF+ (2003 spec: http://www.edfplus.info/specs/edfplus.html) seems more involved.

[rob-luke]

I seem to have deleted that branch when I committed the channel PR. Thats annoying.

I had not read the 2003 spec. I wanted to import files exported from BESA.

[sam81]

OK, I'll try to start a new branch with functions to read EDF files when I have some time

[sam81]

I've started a new branch called "edf" with some preliminary support to read EDF files. I was able to read an EDF file converted from a BDF file using the BDF to EDF converter provided by Biosemi. EDF/EDF+ files can be much more complicated though, for example different channels can have different sampling rates, and can have annotations. These features are not currently supported. Also, I haven't really tested much the new functions.