inconsistencies in edf reader and annotation readers

I have a couple of issues here but bunching them together as they seem related.

1. EDF reader should work with preload=False

If I do:

import mne
from mne.datasets import eegbci
edf_path = eegbci.load_data(subject=1, runs=2)[0]
raw = mne.io.read_raw_edf(edf_path, preload=False)

I get

RuntimeError: EDF+ Annotations (TAL) channel needs to be parsed completely on loading. You must set preload parameter to True.

However, I can actually do:

import mne
from mne.datasets import eegbci
from mne.io.edf.edf import read_annotations_edf

edf_path = eegbci.load_data(subject=1, runs=2)[0]
raw = mne.io.read_raw_edf(edf_path, preload=False, stim_channel=None)

annot = read_annotations_edf(edf_path)
raw.set_annotations(annot)

and it gives me the same result as:

raw2 = mne.io.read_raw_edf(edf_path, preload=True)
assert raw.annotations.duration[0] == raw2.annotations.duration[0]

So, it seems to me that it should already be possible to load EDF files with preload=False as all the necessary components already exist.

2. find_edf_events and mne.events_from_annotations don’t give same results

Here is the code to reproduce (continuing from code above):

events, event_id = mne.events_from_annotations(raw)
events2 = raw.find_edf_events()
print(events)
print(events2)

3. namespaces of read_annotations_xxx

I have to do:

from mne import read_annotations  # for fif files
from mne.io import read_annotations_brainvision  # for brainvision
from mne.io import read_annotations_eeglab  # for eeglab
from mne.io.edf.edf import read_annotations_edf  # for edf

This is quite confusing. In fact, I don’t see a good rational for having different functions as all these different file formats (debatable) since all you need is a filename for most of these readers. So you should be able to triage based on the extension. In any case, having them in the same namespace would already be a start ! (and maybe read_annotations -> read_annotations_fif ?)

4. documentation issues

read_annotations_edf says I need a .vmrk file. This looks incorrect, right?

Happy to help out with these after the mne-bids release. If someone else has time to work before (@massich ?), I am happy to review the code 😃

[larsoner]

FYI to me it is weird to have a read_annotations that triages by file type but no read_raw that does the same. The more consistent fix would be to have read_annotations renamed to read_annotations_fif. But I can live with the inconsistency.

[larsoner]

The conversation went a bit off-topic (to mne.io.read_raw), I think it’s fine to leave closed