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# -*- coding: utf-8 -*- | |
""" | |
Created on Wed Dec 5 12:56:31 2018 | |
@author: skjerns | |
Gist to save a mne.io.Raw object to an EDF file using pyEDFlib | |
(https://github.com/holgern/pyedflib) | |
Disclaimer: | |
- Saving your data this way will result in slight | |
loss of precision (magnitude +-1e-09). | |
- It is assumed that the data is presented in Volt (V), | |
it will be internally converted to microvolt | |
- BDF or EDF+ is selected based on the filename extension | |
- Annotations preserved | |
Update: Since 2021, MNE also supports exporting EDF via edfio: | |
https://mne.tools/stable/generated/mne.export.export_raw.html | |
""" | |
import pyedflib # pip install pyedflib | |
from pyedflib import highlevel # new high-level interface | |
from pyedflib import FILETYPE_BDF, FILETYPE_BDFPLUS, FILETYPE_EDF, FILETYPE_EDFPLUS | |
from datetime import datetime, timezone, timedelta | |
import mne | |
import os | |
def _stamp_to_dt(utc_stamp): | |
"""Convert timestamp to datetime object in Windows-friendly way.""" | |
if 'datetime' in str(type(utc_stamp)): return utc_stamp | |
# The min on windows is 86400 | |
stamp = [int(s) for s in utc_stamp] | |
if len(stamp) == 1: # In case there is no microseconds information | |
stamp.append(0) | |
return (datetime.fromtimestamp(0, tz=timezone.utc) + | |
timedelta(0, stamp[0], stamp[1])) # day, sec, μs | |
def write_mne_edf(mne_raw, fname, picks=None, tmin=0, tmax=None, | |
overwrite=False): | |
""" | |
Saves the raw content of an MNE.io.Raw and its subclasses to | |
a file using the EDF+/BDF filetype | |
pyEDFlib is used to save the raw contents of the RawArray to disk | |
Parameters | |
update 2021: edf export is now also supported in MNE: | |
https://mne.tools/stable/generated/mne.export.export_raw.html | |
---------- | |
mne_raw : mne.io.Raw | |
An object with super class mne.io.Raw that contains the data | |
to save | |
fname : string | |
File name of the new dataset. This has to be a new filename | |
unless data have been preloaded. Filenames should end with .edf | |
picks : array-like of int | None | |
Indices of channels to include. If None all channels are kept. | |
tmin : float | None | |
Time in seconds of first sample to save. If None first sample | |
is used. | |
tmax : float | None | |
Time in seconds of last sample to save. If None last sample | |
is used. | |
overwrite : bool | |
If True, the destination file (if it exists) will be overwritten. | |
If False (default), an error will be raised if the file exists. | |
""" | |
print('did you know EDF export is now supported in MNE via edfio? have a look at https://mne.tools/stable/generated/mne.export.export_raw.html') | |
if not issubclass(type(mne_raw), mne.io.BaseRaw): | |
raise TypeError('Must be mne.io.Raw type') | |
if not overwrite and os.path.exists(fname): | |
raise OSError('File already exists. No overwrite.') | |
# static settings | |
has_annotations = True if len(mne_raw.annotations)>0 else False | |
if os.path.splitext(fname)[-1] == '.edf': | |
file_type = FILETYPE_EDFPLUS if has_annotations else FILETYPE_EDF | |
dmin, dmax = -32768, 32767 | |
else: | |
file_type = FILETYPE_BDFPLUS if has_annotations else FILETYPE_BDF | |
dmin, dmax = -8388608, 8388607 | |
print('saving to {}, filetype {}'.format(fname, file_type)) | |
sfreq = mne_raw.info['sfreq'] | |
date = _stamp_to_dt(mne_raw.info['meas_date']) | |
if tmin: | |
date += timedelta(seconds=tmin) | |
# no conversion necessary, as pyedflib can handle datetime. | |
#date = date.strftime('%d %b %Y %H:%M:%S') | |
first_sample = int(sfreq*tmin) | |
last_sample = int(sfreq*tmax) if tmax is not None else None | |
# convert data | |
channels = mne_raw.get_data(picks, | |
start = first_sample, | |
stop = last_sample) | |
# convert to microvolts to scale up precision | |
channels *= 1e6 | |
# set conversion parameters | |
n_channels = len(channels) | |
# create channel from this | |
try: | |
f = pyedflib.EdfWriter(fname, | |
n_channels=n_channels, | |
file_type=file_type) | |
channel_info = [] | |
ch_idx = range(n_channels) if picks is None else picks | |
keys = list(mne_raw._orig_units.keys()) | |
for i in ch_idx: | |
try: | |
ch_dict = {'label': mne_raw.ch_names[i], | |
'dimension': mne_raw._orig_units[keys[i]], | |
'sample_rate': mne_raw._raw_extras[0]['n_samps'][i], | |
'physical_min': mne_raw._raw_extras[0]['physical_min'][i], | |
'physical_max': mne_raw._raw_extras[0]['physical_max'][i], | |
'digital_min': mne_raw._raw_extras[0]['digital_min'][i], | |
'digital_max': mne_raw._raw_extras[0]['digital_max'][i], | |
'transducer': '', | |
'prefilter': ''} | |
except: | |
ch_dict = {'label': mne_raw.ch_names[i], | |
'dimension': mne_raw._orig_units[keys[i]], | |
'sample_rate': sfreq, | |
'physical_min': channels.min(), | |
'physical_max': channels.max(), | |
'digital_min': dmin, | |
'digital_max': dmax, | |
'transducer': '', | |
'prefilter': ''} | |
channel_info.append(ch_dict) | |
f.setPatientCode(mne_raw._raw_extras[0]['subject_info'].get('id', '0')) | |
f.setPatientName(mne_raw._raw_extras[0]['subject_info'].get('name', 'noname')) | |
f.setTechnician('mne-gist-save-edf-skjerns') | |
f.setSignalHeaders(channel_info) | |
f.setStartdatetime(date) | |
f.writeSamples(channels) | |
for annotation in mne_raw.annotations: | |
onset = annotation['onset'] | |
duration = annotation['duration'] | |
description = annotation['description'] | |
f.writeAnnotation(onset, duration, description) | |
except Exception as e: | |
raise e | |
finally: | |
f.close() | |
return True |
Yes, I had the same problem. I solved it by changing line 76 to date = mne_raw.info['meas_date']
. However then I got a new problem and I actually gave up :P Let me know if you succed!
I've adapted the script.
@datalw can you check if it works now?
@skjerns Thanks a lot for the swift response! I tried the adapted version and got the following error:
----> 3 if 'datetime' in type(utc_stamp): return utc_stamp
4 # The min on windows is 86400
5 stamp = [int(s) for s in utc_stamp]
TypeError: argument of type 'type' is not iterable
So I changed if 'datetime' in type(utc_stamp):
to if 'datetime' in str(type(utc_stamp))
and it works :D Would you mind to adapt it again?
Thanks a lot for the great work!
@LunaHub it works for me so far, you could try it again : )
oops, yes didnt test it, thank's, I corrected it
I have used the gist for a while, it is really awesome, especially for saving the preprocessed data!
I am here again for a follow-up question. So far the files without annotations have been saved successfully. However for a file with annotations, the raw.times in the saved file was incorrect. I have looked into the code and found out the problem might be due to this line
'sample_rate': mne_raw._raw_extras[0]['n_samps'][i]
mne_raw.info['sfreq']
gives 256, but mne_raw._raw_extras[0]['n_samps'][i]
gives 2048 instead.
Since I have never dealt with _raw_extras, I tried to find some information about _raw_extras in mne documention, but failed.
Does anyone know how to solve this problem, or how I can proceed? Or is this a bug in _raw_extras?
I am not familiar with raw._raw_extras
you might be able to reach a wider audience that wrote that part of the code on Gitter unless someone on this thread knows https://gitter.im/mne-tools/mne-python
@datalw did you resample the data? was one of original sample frequencies 2048?
to be honest, I just hacked this snippet together and changed it often over time, I'm also not very familiar with the mne
internals. If you find a solution, let me know! I'm still in favor of integrating edf writing compatibility inside mne
, but currently they don't want to introduce optional dependencies. maybe that changes as a python-native implementation of edflib
has been published last month :)
So this still isn't incorporated into mne-python, any chance it ever will? Been a few years.
Feel free to ask this directly at MNE: https://github.com/mne-tools/mne-python/issues or the gitter https://gitter.im/mne-tools/mne-python
The problem was the additional dependency on pyedflib
and that pyedflib
uses Cython to compile some C libraries, which they did not want to include (afaik, and which I somehow understand).
However, we could ask if it would be possible to include an optional dependency on pyedflib. Additionally, EDDlib has just released a Python-only-version which would solve some problems :) but its quite slow (it's Python, nevertheless)
@alexrockhill @skjerns Thanks a lot for the reply and sorry for my delayed answer. I plan to come back to this issue in the next couple of weeks and if I find a solution I will let you @skjerns know ; )
Hello, thanks a lot for the great work! I am having one problem when using this script. When I try to open the resulted edf file this message came up "Error, number of datarecords is 0, expected >0. You can fix this problem with the header editor, check the manual for details. File is not a valid EDF or BDF file.". I am not quite sure why is this the case and I wonder if anyone is having the same problem or has any solution.
Thanks a lot!
That's a bit hard to diagnose what's going on without sharing a minimally reproducible example that someone else can run on their machine.
It sounds like maybe your mne.io.Raw
object didn't have any data in it or any data of type eeg
, grad
, mag
or seeg
. See https://mne.tools/stable/generated/mne.io.Raw.html#mne.io.Raw.set_channel_types.
That's a bit hard to diagnose what's going on without sharing a minimally reproducible example that someone else can run on their machine.
It sounds like maybe your
mne.io.Raw
object didn't have any data in it or any data of typeeeg
,grad
,mag
orseeg
. See https://mne.tools/stable/generated/mne.io.Raw.html#mne.io.Raw.set_channel_types.
@alexrockhill Hello, thanks a lot for the reply. This is the piece of code I used when creating the mne.io.Raw
object.
sample_data_raw_file = os.path.join("filename.edf")
raw = mne.io.read_raw_edf(sample_data_raw_file)
My original document is already in .edf, I put the file through some processing in mne-python and I would want to save the end-product as .edf using your script. Thanks a lot for your help!
From my experience reading in edf files, often the data types are not correctly set by mne by default. I would try setting all your channel types to eeg
I assume but whatever type they are and saving again. I'd be interested to know if that works.
Also, I helped a bit but the thanks definitely goes to @skjerns for this gist.
Maybe this will help
import mne
raw_fname = 'filename.edf'
raw = mne.io.read_raw_edf(raw_fname)
raw = raw.set_channel_types({ch: 'eeg' for ch in raw.ch_names})
@alexrockhill
Thanks for the reply. I have tried setting the channel types to eeg
using raw = raw.set_channel_types({ch: 'eeg' for ch in raw.ch_names})
, but the resulting file still can't be opened.
I am having the same. My guess is that there is some unexpected bug occurs while you reading the raw data from edf. Is there any method to sure I read the edf correctly?
Ok, that was just an informed guess but I couldn't tell you what's wrong because I don't have access to your data.
I realized that the smaller the original file I use the smaller the resulting file that is saved. But nomatter how big my original file is, the resulting file is always too small to be opened. When I called the function I called it this way write_mne_edf(raw,'testfile.edf', overwrite=True)
. I wonder if I am not aware of some details from the script resulting in this error of getting an extremely small file.
It is difficult to help you without having the original file to work with. Feel free to upload the file somewhere (eg wetransfer) and post the link here. Alternatively, if the data is sensitive, send it privately to [email protected]
It is difficult to help you without having the original file to work with. Feel free to upload the file somewhere (eg wetransfer) and post the link here. Alternatively, if the data is sensitive, send it privately to [email protected]
Hello, thank you very much for your reply. I have sent an email to the address provided. Thanks!
There was an Exception raised during the file you sent, as the date
wasn't set correctly, so the resulting file was just a leftover of an incomplete write. I changed the gist to raise an Exception explicitly and not just print it. It should work now. This was due to a bug in pyedflib, which I fixed now.
There was an Exception raised during the file you sent, as the
date
wasn't set correctly, so the resulting file was just a leftover of an incomplete write. I changed the gist to raise an Exception explicitly and not just print it. It should work now. This was due to a bug in pyedflib, which I fixed now.
Thank you very much for your help, it works perfectly now!
Hi @skjerns! Thank you for this great gist, we've been using it a lot in my lab. If the option of integrating it directly into MNE ever comes back to the table (now that there is a native Python implementation), I'd be happy to vouch for it!
Just a quick comment on the code, wouldn't it make more sense to update the date
so that it starts at tmin
, and not meas_date
? Concretely, just adding a timedelta(seconds=tmin) to the date
datetime?
Thanks,
Raphael
The Python native implementation of edflib
is unfortunately extremely slow (I posted a benchmark here), up to 20x slower. So I don't think implementation in mne is going to come soon. But I see what I can do w.r.t this issue, as it seems to be a major feature lacking in mne
. It should be possible to speed up quite a bit, with knowing a bit of Python internals and bottlenecks.
good one for the tmin! I'll implement that. I actually never use this gist myself, so I rely on users to improve it :)
Hello, and thank you for your great job!
I have a little problem because when I convert a file using your method, it goes from 1h duration to 8h duration (probably related to the sample rate, which is transformed from 2048 to 256Hz somewhere in the process). However, I change absolutely nothing, I just load my .edf data (duration = 1h), use write_edf, load the new .edf data (duration = 8h).
Edit : I solved the problem by changing the following code. Basically I just changed the 'sample_rate' parameter into the ch_dict.
try:
ch_dict = {'label': mne_raw.ch_names[i],
'dimension': mne_raw._orig_units[keys[i]],
#'sample_rate': mne_raw._raw_extras[0]['n_samps'][i],
'sample_rate': mne_raw.info["sfreq"],
'physical_min': mne_raw._raw_extras[0]['physical_min'][i],
'physical_max': mne_raw._raw_extras[0]['physical_max'][i],
'digital_min': mne_raw._raw_extras[0]['digital_min'][i],
'digital_max': mne_raw._raw_extras[0]['digital_max'][i],
'transducer': '',
'prefilter': ''}
except:
ch_dict = {'label': mne_raw.ch_names[i],
'dimension': mne_raw._orig_units[keys[i]],
#'sample_rate': sfreq,
'sample_rate': mne_raw.info["sfreq"],
'physical_min': channels.min(),
'physical_max': channels.max(),
'digital_min': dmin,
'digital_max': dmax,
'transducer': '',
'prefilter': ''}
Hello, thanks a lot for this amazing script. I realize that the resulting file saved from this script will be in the folder which the original data is located. I wonder if there is any way we can change where the output file will be within the script. Thank you.
Hello, thanks a lot for this amazing script. I realize that the resulting file saved from this script will be in the folder which the original data is located. I wonder if there is any way we can change where the output file will be within the script. Thank you.
Hi, you can just set "fname" to the full path you want (folderpath/filename.edf) when you call the write_mne_edf() function.
Hi, thanks for your great work.
I'm trying to fit this code into mff
files, but I'm not sure what does channels *= 1e6
do. Can someone give more explanation? Thanks.
It is assumed that the data is passed from MNE is in Volts (see disclaimer of the function, this is default in MNE afaik), even though most values recorded with EEG are in the mV or uV range. However, as EDF+ is only using 16-bit precision, such small values easily lose much precision. Therefore values are converted from Volt to Microvolt, where less precision is lost. The physical dimension is then added to the EDF+ header, so it should load correctly. To be honest, now that I'm re-reading the code I'm struggeling myself to trust that this also works in cases where data is not EEG (e.g. with data in nT
like MEG). I haven't used MNE ever since, so I don't really know.
Hi,
this gist is really great idea! Just the functionality, which I have been searched in mne and did not find. A great supplement. Big thanks to you!
I tried to save the preprocessed mne raw object into a new edf, and got the following error
...
raw.info['meas_date'] in my script gives me:
Have you encoutered this problem?