[ENH] Added discontinuous datatype for EEG and iEEG

[wouterpotters]

Problem: EDF+ files (and other file types like BrainVision) can be continuous (EDF+C, BrainVision without discontinuous boundary markers) or discontinuous (EDF+D, BrainVision with discontinuous boundary markers). This can be essential information in processing of data (i.e. not all EDF readers support EDF+D or discontinuous BrainVision data).

See also https://www.edfplus.info/specs/edfplus.html and https://pressrelease.brainproducts.com/markers/#4

Suggestion: mark data as continuous or discontinuous (or epoched)

Note: discontinuous data is not the same as epoched data!

Please let me know what you think!

[robertoostenveld]

BrainVision files can also include markers that indicate the time of discontinuous boundaries between otherwise continuous segments, e.g. when pausing the recording. I don't think it applies to the other formats.

[robertoostenveld]

the difference between discontinuous (variable length segments) and epoched (identical length segments) should be explained in the text, not only be mentioned in the table.

[sappelhoff]

@wouterpotters our linter complains that the table pipe characters in the markdown (|) are not aligned properly, see: https://travis-ci.com/bids-standard/bids-specification/builds/121065179

Can you fix this, please? See here for a Markdown cheat sheet on tables: https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet#tables

Apart from this I agree with @robertoostenveld that a short part added in the text will be helpful.

[wouterpotters]

Dear @robertoostenveld and @sappelhoff, thank you for the useful suggestions and your time. Tried to incorporate all of the suggestions. The checks now pass successfully (didn't check them when I submitted this; will do so for future pull requests).
Do not know about the BrainVision format, but as far as I can tell this pull request could apply to both edf and brainvision without explicitly naming them in the text.

[sappelhoff]

Thanks for the updates @wouterpotters I am fine with the changes made 👍

One more request: Could you please add yourself to the contributors file? --> https://github.com/bids-standard/bids-specification/blob/master/src/99-appendices/01-contributors.md

We use this list to acknowledge people who have helped the BIDS standard to progress :-)

[wouterpotters]

Thanks for the updates @wouterpotters I am fine with the changes made 👍

One more request: Could you please add yourself to the contributors file? --> https://github.com/bids-standard/bids-specification/blob/master/src/99-appendices/01-contributors.md

We use this list to acknowledge people who have helped the BIDS standard to progress :-)

Done.

[sappelhoff]

great, I'll leave this open for a bit more to give @robertoostenveld a chance to approve or request changes.

Note: You might also have to rebase this PR (see the conflicting file)

[robertoostenveld]

please merge my suggestion, after that it can be included in the release.

[wouterpotters]

Included all suggestions by @robertoostenveld and @sappelhoff. Thank you for your time and effort into the BIDS standard. Great initiative!

As far as I can see it's now ready to merge into the main branch.

[sappelhoff]

Thanks for your contribution @wouterpotters!