function [type] = ft_filetype(filename, desired, varargin)

% FT_FILETYPE determines the filetype of many EEG/MEG/MRI data files by

% looking at the name, extension and optionally (part of) its contents.

% It tries to determine the global type of file (which usually

% corresponds to the manufacturer, the recording system or to the

% software used to create the file) and the particular subtype (e.g.

% continuous, average).

%

% Use as

% type = ft_filetype(filename)

% type = ft_filetype(dirname)

%

% This gives you a descriptive string with the data type, and can be

% used in a switch-statement. The descriptive string that is returned

% usually is something like 'XXX_YYY'/ where XXX refers to the

% manufacturer and YYY to the type of the data.

%

% Alternatively, use as

% flag = ft_filetype(filename, type)

% flag = ft_filetype(dirname, type)

% This gives you a boolean flag (0 or 1) indicating whether the file

% is of the desired type, and can be used to check whether the

% user-supplied file is what your subsequent code expects.

%

% Alternatively, use as

% flag = ft_filetype(dirlist, type)

% where the dirlist contains a list of files contained within one

% directory. This gives you a boolean vector indicating for each file

% whether it is of the desired type.

%

% Most filetypes of the following manufacturers and/or software programs are recognized

% - 4D/BTi

% - AFNI

% - ASA

% - Analyse

% - Analyze/SPM

% - BESA

% - Bioimage Suite *.mgrid

% - BrainSuite

% - BrainVisa

% - BrainVision

% - Curry

% - Dataq

% - EDF

% - EEProbe

% - Elektra/Neuromag

% - EEGsynth *.tsv

% - FreeSurfer

% - LORETA

% - Localite

% - MINC

% - Neuralynx

% - Neuroscan

% - Nihon Koden *.m00

% - OpenVibe MATLAB files *.mat

% - Plexon

% - SR Research Eyelink

% - SensoMotoric Instruments (SMI) *.txt

% - Tobii *.tsv

% - Stanford *.ply

% - Tucker Davis Technology

% - CTF

% - Yokogawa & Ricoh

% - nifti, gifti

% - Nicolet *.e (currently from Natus, formerly Carefusion, Viasys and Taugagreining. Also known as Oxford/Teca/Medelec Valor Nervus)

% - Biopac *.acq

% - AnyWave *.ades

% - Qualisys *.tsv

% - Mrtrix *.mif

% - MAUS *.TextGrid

% - Neurodata Without Borders *.nwb

% - PhysioNet *.hea and *.dat

% - NIRx *.tpl, *.wl1 and *.wl2

% - York Instruments *.meghdf5

% Copyright (C) 2003-2023, Robert Oostenveld

%

% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org

% for the documentation and details.

%

% FieldTrip is free software: you can redistribute it and/or modify

% it under the terms of the GNU General Public License as published by

% the Free Software Foundation, either version 3 of the License, or

% (at your option) any later version.

%

% FieldTrip is distributed in the hope that it will be useful,

% but WITHOUT ANY WARRANTY; without even the implied warranty of

% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

% GNU General Public License for more details.

%

% You should have received a copy of the GNU General Public License

% along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.

%

% $Id$

% these are for speeding up subsequent calls with the same input arguments

persistent previous_argin previous_argout previous_pwd

if nargin<2

% ensure that all input arguments are defined

desired = [];

end

current_argin = {filename, desired, varargin{:}};

current_pwd = pwd;

if isequal(current_argin, previous_argin) && isequal(current_pwd, previous_pwd)

% don't do the detection again, but return the previous value from cache

type = previous_argout{1};

return

end

if isa(filename, 'memmapfile')

filename = filename.Filename;

end

% % get the optional arguments

% checkheader = ft_getopt(varargin, 'checkheader', true);

%

% if ~checkheader

% % assume that the header is always ok, e.g when the file does not yet exist

% % this replaces the normal function with a function that always returns true

% filetype_check_header = @filetype_true;

% end

if iscell(filename)

if ~isempty(desired)

% perform the test for each filename, return a boolean vector

type = false(size(filename));

else

% return a string with the type for each filename

type = cell(size(filename));

end

for i=1:length(filename)

if strcmp(filename{i}(end), '.')

% do not recurse into this directory or the parent directory

continue

else

if iscell(type)

type{i} = ft_filetype(filename{i}, desired);

else

type(i) = ft_filetype(filename{i}, desired);

end

end

end

return

end

% start with unknown values

type = 'unknown';

manufacturer = 'unknown';

content = 'unknown';

if isempty(filename)

if isempty(desired)

% return the "unknown" outputs

return

else

% return that it is a non-match

type = false;

return

end

end

% the parts of the filename are used further down

if isfolder(filename)

[p, f, x] = fileparts(filename);

p = filename; % the full path to the directory name

d = f; % the last part of the directory name

f = '';

x = '';

else

[p, f, x] = fileparts(filename);

end

% prevent this test if the filename resembles an URI, i.e. like "scheme://"

if ~contains(filename , '://') && isfolder(filename)

% the directory listing is needed below

ls = dir(filename);

% remove the parent directory and the directory itself from the list

ls = ls(~strcmp({ls.name}, '.'));

ls = ls(~strcmp({ls.name}, '..'));

for i=1:length(ls)

% make sure that the directory listing includes the complete path

ls(i).name = fullfile(filename, ls(i).name);

end

end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% start determining the filetype

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% this checks for a compressed file (of arbitrary type)

if filetype_check_extension(filename, 'zip')...

|| (filetype_check_extension(filename, '.gz') && ~filetype_check_extension(filename, '.nii.gz'))...

|| filetype_check_extension(filename, 'tgz')...

|| filetype_check_extension(filename, 'tar')

type = 'compressed';

manufacturer = 'undefined';

content = 'unknown, extract first';

% these are some streams for asynchronous BCI

elseif filetype_check_uri(filename, 'fifo')

type = 'fcdc_fifo';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'buffer')

type = 'fcdc_buffer';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'mysql')

type = 'fcdc_mysql';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'tcp')

type = 'fcdc_tcp';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'udp')

type = 'fcdc_udp';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'rfb')

type = 'fcdc_rfb';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'serial')

type = 'fcdc_serial';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'stream';

elseif filetype_check_uri(filename, 'global')

type = 'fcdc_global';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'global variable';

elseif filetype_check_uri(filename, 'shm')

type = 'ctf_shm';

manufacturer = 'CTF';

content = 'real-time shared memory buffer';

elseif filetype_check_uri(filename, 'empty')

type = 'empty';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = '/dev/null';

% known CTF file types

elseif isfolder(filename) && filetype_check_extension(filename, '.ds') && exist(fullfile(filename, [f '.res4']), 'file')

type = 'ctf_ds';

manufacturer = 'CTF';

content = 'MEG dataset';

elseif isfolder(filename) && ~isempty(dir(fullfile(filename, '*.res4'))) && ~isempty(dir(fullfile(filename, '*.meg4')))

type = 'ctf_ds';

manufacturer = 'CTF';

content = 'MEG dataset';

elseif filetype_check_extension(filename, '.res4') && (filetype_check_header(filename, 'MEG41RS') || filetype_check_header(filename, 'MEG42RS') || filetype_check_header(filename, 'MEG4RES') || filetype_check_header(filename, 'MEG3RES')) %'MEG3RES' pertains to ctf64.ds

type = 'ctf_res4';

manufacturer = 'CTF';

content = 'MEG/EEG header information';

elseif filetype_check_extension(filename, '.meg4') && (filetype_check_header(filename, 'MEG41CP') || filetype_check_header(filename, 'MEG4CPT')) %'MEG4CPT' pertains to ctf64.ds

type = 'ctf_meg4';

manufacturer = 'CTF';

content = 'MEG/EEG';

elseif strcmp(f, 'MarkerFile') && filetype_check_extension(filename, '.mrk') && filetype_check_header(filename, 'PATH OF DATASET:')

type = 'ctf_mrk';

manufacturer = 'CTF';

content = 'marker file';

elseif filetype_check_extension(filename, '.mri') && filetype_check_header(filename, 'CTF_MRI_FORMAT VER 2.2')

type = 'ctf_mri';

manufacturer = 'CTF';

content = 'MRI';

elseif filetype_check_extension(filename, '.mri') && filetype_check_header(filename, 'CTF_MRI_FORMAT VER 4', 31)

type = 'ctf_mri4';

manufacturer = 'CTF';

content = 'MRI';

elseif filetype_check_extension(filename, '.hdm')

type = 'ctf_hdm';

manufacturer = 'CTF';

content = 'volume conduction model';

elseif filetype_check_extension(filename, '.hc')

type = 'ctf_hc';

manufacturer = 'CTF';

content = 'headcoil locations';

elseif filetype_check_extension(filename, '.shape')

type = 'ctf_shape';

manufacturer = 'CTF';

content = 'headshape points';

elseif filetype_check_extension(filename, '.shape_info')

type = 'ctf_shapeinfo';

manufacturer = 'CTF';

content = 'headshape information';

elseif filetype_check_extension(filename, '.wts')

type = 'ctf_wts';

manufacturer = 'CTF';

content = 'SAM coefficients, i.e. spatial filter weights';

elseif filetype_check_extension(filename, '.svl')

type = 'ctf_svl';

manufacturer = 'CTF';

content = 'SAM (pseudo-)statistic volumes';

% known Micromed file types

elseif filetype_check_extension(filename, '.trc') && filetype_check_header(filename, '* MICROMED')

type = 'micromed_trc';

manufacturer = 'Micromed';

content = 'Electrophysiological data';

% known Neuromag file types

elseif filetype_check_extension(filename, '.fif')

type = 'neuromag_fif';

manufacturer = 'Neuromag';

content = 'MEG header and data';

elseif filetype_check_extension(filename, '.mesh')

type = 'neuromag_mesh';

manufacturer = 'Neuromag';

content = 'triangulated surface mesh';

elseif filetype_check_extension(filename, '.bdip')

type = 'neuromag_bdip';

manufacturer = 'Neuromag';

content = 'dipole model';

elseif filetype_check_extension(filename, '.eve') && exist(fullfile(p, [f '.fif']), 'file')

type = 'neuromag_eve'; % these are being used by Tristan Technologies for the BabySQUID system

manufacturer = 'Neuromag';

content = 'events';

elseif filetype_check_extension(filename, '.log') && filetype_check_header(filename, '*** This is Elekta Neuromag MaxFilter', 61)

type = 'neuromag_maxfilterlog';

manufacturer = 'Neuromag';

content = 'MaxFilter log information';

elseif filetype_check_extension(filename, '.pos') && filetype_check_header(filename, ' Time q1 ', 0)

type = 'neuromag_headpos';

manufacturer = 'Neuromag';

content = 'MaxFilter head position information';

elseif filetype_check_extension(filename, '.iso') && filetype_check_header(filename, char([0 0 0 100]))

type = 'neuromag_iso';

manufacturer = 'Neuromag';

content = 'Isotrack digitizer points';

elseif strcmp(filename, 'sss_cal.dat')

type = 'neuromag_cal';

manufacturer = 'Neuromag';

content = 'Fine calibration';

% known Yokogawa & Ricoh file types

elseif filetype_check_extension(filename, '.ave') || filetype_check_extension(filename, '.sqd')

if ~isricohmegfile(filename)

type = 'yokogawa_ave';

manufacturer = 'Yokogawa';

content = 'averaged MEG data';

else

type = 'ricoh_ave';

manufacturer = 'Ricoh';

content = 'averaged MEG data';

end

elseif filetype_check_extension(filename, '.con')

if ~isricohmegfile(filename)

type = 'yokogawa_con';

manufacturer = 'Yokogawa';

content = 'continuous MEG data';

else

type = 'ricoh_con';

manufacturer = 'Ricoh';

content = 'continuous MEG data';

end

elseif filetype_check_extension(filename, '.raw') && filetype_check_header(filename, char([0 0 0 0])) % FIXME, this detection should possibly be improved

type = 'yokogawa_raw';

manufacturer = 'Yokogawa';

content = 'evoked/trialbased MEG data';

elseif filetype_check_extension(filename, '.mrk') && filetype_check_header(filename, char([0 0 0 0])) % FIXME, this detection should possibly be improved

if ~isricohmegfile(filename)

type = 'yokogawa_mrk';

manufacturer = 'Yokogawa';

content = 'headcoil locations';

else

type = 'ricoh_mrk';

manufacturer = 'Ricoh';

content = 'headcoil locations';

end

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-coregis')) == 1

type = 'yokogawa_coregis';

manufacturer = 'Yokogawa';

content = 'exported fiducials';

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-calib')) == 1

type = 'yokogawa_calib';

manufacturer = 'Yokogawa';

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-channel')) == 1

type = 'yokogawa_channel';

manufacturer = 'Yokogawa';

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-property')) == 1

type = 'yokogawa_property';

manufacturer = 'Yokogawa';

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-TextData')) == 1

type = 'yokogawa_textdata';

manufacturer = 'Yokogawa';

elseif filetype_check_extension(filename, '.txt') && numel(strfind(filename,'-FLL')) == 1

type = 'yokogawa_fll';

manufacturer = 'Yokogawa';

elseif filetype_check_extension(filename, '.hsp')

type = 'yokogawa_hsp';

manufacturer = 'Yokogawa';

% Neurosim files; this has to go before the 4D detection

elseif ~isfolder(filename) && (strcmp(f,'spikes') || filetype_check_header(filename,'# Spike information'))

type = 'neurosim_spikes';

manufacturer = 'Jan van der Eerden (DCCN)';

content = 'simulated spikes';

elseif ~isfolder(filename) && (strcmp(f,'evolution') || filetype_check_header(filename,'# Voltages'))

type = 'neurosim_evolution';

manufacturer = 'Jan van der Eerden (DCCN)';

content = 'simulated membrane voltages and currents';

elseif ~isfolder(filename) && (strcmp(f,'signals') || filetype_check_header(filename,'# Internal',2))

type = 'neurosim_signals';

manufacturer = 'Jan van der Eerden (DCCN)';

content = 'simulated network signals';

elseif isfolder(filename) && exist(fullfile(filename, 'signals'), 'file') && exist(fullfile(filename, 'spikes'), 'file')

type = 'neurosim_ds';

manufacturer = 'Jan van der Eerden (DCCN)';

content = 'simulated spikes and continuous signals';

% known 4D/BTI file types

elseif filetype_check_extension(filename, '.pdf') && filetype_check_header(filename, 'E|lk') % I am not sure whether this header always applies

type = '4d_pdf';

manufacturer = '4D/BTI';

content = 'raw MEG data (processed data file)';

elseif exist([filename '.m4d'], 'file') && exist([filename '.xyz'], 'file') % these two ascii header files accompany the raw data

type = '4d_pdf';

manufacturer = '4D/BTI';

content = 'raw MEG data (processed data file)';

elseif filetype_check_extension(filename, '.m4d') && exist([filename(1:(end-3)) 'xyz'], 'file') % these come in pairs

type = '4d_m4d';

manufacturer = '4D/BTI';

content = 'MEG header information';

elseif filetype_check_extension(filename, '.xyz') && exist([filename(1:(end-3)) 'm4d'], 'file') % these come in pairs

type = '4d_xyz';

manufacturer = '4D/BTI';

content = 'MEG sensor positions';

elseif isequal(f, 'hs_file') % the filename is "hs_file"

type = '4d_hs';

manufacturer = '4D/BTI';

content = 'head shape';

elseif length(filename)>=4 && contains(filename,',rf')

type = '4d';

manufacturer = '4D/BTi';

content = '';

elseif filetype_check_extension(filename, '.el.ascii') && filetype_check_ascii(filename, 20) % assume that there are at least 20 bytes in the file, the example one has 4277 bytes

type = '4d_el_ascii';

manufacturer = '4D/BTi';

content = 'electrode positions';

% known EEProbe file types

elseif filetype_check_extension(filename, '.cnt') && (filetype_check_header(filename, 'RIFF') || filetype_check_header(filename, 'RF64'))

type = 'eep_cnt';

manufacturer = 'EEProbe';

content = 'EEG';

elseif filetype_check_extension(filename, '.avr') && filetype_check_header(filename, char([38 0 16 0]))

type = 'eep_avr';

manufacturer = 'EEProbe';

content = 'ERP';

elseif filetype_check_extension(filename, '.trg')

type = 'eep_trg';

manufacturer = 'EEProbe';

content = 'trigger information';

elseif filetype_check_extension(filename, '.rej')

type = 'eep_rej';

manufacturer = 'EEProbe';

content = 'rejection marks';

% the yokogawa_mri has to be checked prior to asa_mri, because this one is more strict

elseif filetype_check_extension(filename, '.mri') && filetype_check_header(filename, char(0)) % FIXME, this detection should possibly be improved

type = 'yokogawa_mri';

manufacturer = 'Yokogawa';

content = 'anatomical MRI';

% known ASA file types

elseif filetype_check_extension(filename, '.elc')

type = 'asa_elc';

manufacturer = 'ASA';

content = 'electrode positions';

elseif filetype_check_extension(filename, '.vol')

type = 'asa_vol';

manufacturer = 'ASA';

content = 'volume conduction model';

elseif filetype_check_extension(filename, '.bnd')

type = 'asa_bnd';

manufacturer = 'ASA';

content = 'boundary element model details';

elseif filetype_check_extension(filename, '.msm')

type = 'asa_msm';

manufacturer = 'ASA';

content = 'ERP';

elseif filetype_check_extension(filename, '.msr')

type = 'asa_msr';

manufacturer = 'ASA';

content = 'ERP';

elseif filetype_check_extension(filename, '.dip')

% FIXME, can also be CTF dipole file

type = 'asa_dip';

manufacturer = 'ASA';

elseif filetype_check_extension(filename, '.mri')

% FIXME, can also be CTF mri file

type = 'asa_mri';

manufacturer = 'ASA';

content = 'MRI image header';

elseif filetype_check_extension(filename, '.iso') && ~filetype_check_header(filename, char([0 0 0 100]))

type = 'asa_iso';

manufacturer = 'ASA';

content = 'MRI image data';

% known BCI2000 file types

elseif filetype_check_extension(filename, '.dat') && (filetype_check_header(filename, 'BCI2000') || filetype_check_header(filename, 'HeaderLen='))

type = 'bci2000_dat';

manufacturer = 'BCI2000';

content = 'continuous EEG';

% known Neuroscan file types

elseif filetype_check_extension(filename, '.avg') && filetype_check_header(filename, 'Version 3.0')

type = 'ns_avg';

manufacturer = 'Neuroscan';

content = 'averaged EEG';

elseif filetype_check_extension(filename, '.cnt') && filetype_check_header(filename, 'Version 3.0')

type = 'ns_cnt';

manufacturer = 'Neuroscan';

content = 'continuous EEG';

elseif filetype_check_extension(filename, '.eeg') && filetype_check_header(filename, 'Version 3.0')

type = 'ns_eeg';

manufacturer = 'Neuroscan';

content = 'epoched EEG';

elseif filetype_check_extension(filename, '.eeg') && filetype_check_header(filename, 'V3.0')

type = 'neuroprax_eeg';

manufacturer = 'eldith GmbH';

content = 'continuous EEG';

elseif filetype_check_extension(filename, '.ee_')

type = 'neuroprax_mrk';

manufacturer = 'eldith GmbH';

content = 'EEG markers';

% known Analyze & SPM file types

elseif filetype_check_extension(filename, '.hdr')

type = 'analyze_hdr';

manufacturer = 'Mayo Analyze';

content = 'PET/MRI image header';

elseif filetype_check_extension(filename, '.img')

type = 'analyze_img';

manufacturer = 'Mayo Analyze';

content = 'PET/MRI image data';

elseif filetype_check_extension(filename, '.mnc')

type = 'minc';

content = 'MRI image data';

elseif filetype_check_extension(filename, '.nii') && filetype_check_header(filename, {[92 1 0 0], [0 0 1 92]}) % header starts with the number 348

type = 'nifti';

content = 'MRI image data';

elseif filetype_check_extension(filename, '.nii') && filetype_check_header(filename, {[28 2 0 0], [0 0 2 28]}) % header starts with the number 540

type = 'nifti2';

content = 'MRI image data';

% known FSL file types

elseif filetype_check_extension(filename, '.nii.gz')

type = 'nifti_gz';

content = 'MRI image data';

% known LORETA file types

elseif filetype_check_extension(filename, '.lorb')

type = 'loreta_lorb';

manufacturer = 'old LORETA';

content = 'source reconstruction';

elseif filetype_check_extension(filename, '.slor')

type = 'loreta_slor';

manufacturer = 'sLORETA';

content = 'source reconstruction';

% known AFNI file types

elseif filetype_check_extension(lower(filename), '.brik')

type = 'afni_brik';

content = 'MRI image data';

elseif filetype_check_extension(lower(filename), '.head')

type = 'afni_head';

content = 'MRI header data';

% known BrainVison file types

elseif filetype_check_extension(filename, '.vhdr')

type = 'brainvision_vhdr';

manufacturer = 'BrainProducts';

content = 'EEG header';

elseif filetype_check_extension(filename, '.vmrk')

type = 'brainvision_vmrk';

manufacturer = 'BrainProducts';

content = 'EEG markers';

elseif filetype_check_extension(filename, '.vabs')

type = 'brainvision_vabs';

manufacturer = 'BrainProducts';

content = 'Brain Vison Analyzer macro';

elseif filetype_check_extension(filename, '.eeg') && exist(fullfile(p, [f '.vhdr']), 'file')

type = 'brainvision_eeg';

manufacturer = 'BrainProducts';

content = 'continuous EEG data';

elseif filetype_check_extension(filename, '.seg')

type = 'brainvision_seg';

manufacturer = 'BrainProducts';

content = 'segmented EEG data';

elseif filetype_check_extension(filename, '.dat') && exist(fullfile(p, [f '.vhdr']), 'file') &&...

~filetype_check_header(filename, 'HeaderLen=') && ~filetype_check_header(filename, 'BESA_SA_IMAGE') &&...

~(exist(fullfile(p, [f '.gen']), 'file') || exist(fullfile(p, [f '.generic']), 'file'))

% WARNING this is a very general name, it could be exported BrainVision

% data but also a BESA beamformer source reconstruction or BCI2000

type = 'brainvision_dat';

manufacturer = 'BrainProducts';

content = 'exported EEG data';

elseif filetype_check_extension(filename, '.marker')

type = 'brainvision_marker';

manufacturer = 'BrainProducts';

content = 'rejection markers';

% known Polhemus file types

elseif filetype_check_extension(filename, '.pos')

type = 'polhemus_pos';

manufacturer = 'BrainProducts/CTF/Polhemus?'; % actually I don't know whose software it is

content = 'electrode positions';

% known Blackrock Microsystems file types

elseif strncmp(x,'.ns',3) && (filetype_check_header(filename, 'NEURALCD') || filetype_check_header(filename, 'NEURALSG'))

type = 'blackrock_nsx';

manufacturer = 'Blackrock Microsystems';

content = 'conintuously sampled data';

elseif filetype_check_extension(filename, '.nev') && filetype_check_header(filename, 'NEURALEV')

type = 'blackrock_nev';

manufacturer = 'Blackrock Microsystems';

contenct = 'extracellular electrode spike information';

% known Neuralynx file types

elseif filetype_check_extension(filename, '.nev') || filetype_check_extension(filename, '.Nev')

type = 'neuralynx_nev';

manufacturer = 'Neuralynx';

content = 'event information';

elseif filetype_check_extension(filename, '.ncs') && filetype_check_header(filename, '####')

type = 'neuralynx_ncs';

manufacturer = 'Neuralynx';

content = 'continuous single channel recordings';

elseif filetype_check_extension(filename, '.nse') && filetype_check_header(filename, '####')

type = 'neuralynx_nse';

manufacturer = 'Neuralynx';

content = 'spike waveforms';

elseif filetype_check_extension(filename, '.nts') && filetype_check_header(filename, '####')

type = 'neuralynx_nts';

manufacturer = 'Neuralynx';

content = 'timestamps only';

elseif filetype_check_extension(filename, '.nvt')

type = 'neuralynx_nvt';

manufacturer = 'Neuralynx';

content = 'video tracker';

elseif filetype_check_extension(filename, '.nst')

type = 'neuralynx_nst';

manufacturer = 'Neuralynx';

content = 'continuous stereotrode recordings';

elseif filetype_check_extension(filename, '.ntt')

type = 'neuralynx_ntt';

manufacturer = 'Neuralynx';

content = 'continuous tetrode recordings';

elseif strcmpi(f, 'logfile') && strcmpi(x, '.txt') % case insensitive

type = 'neuralynx_log';

manufacturer = 'Neuralynx';

content = 'log information in ASCII format';

elseif contains(lower(f), 'dma') && strcmpi(x, '.log') % this is not a very strong detection

type = 'neuralynx_dma';

manufacturer = 'Neuralynx';

content = 'raw aplifier data directly from DMA';

elseif filetype_check_extension(filename, '.nrd') % see also above, since Cheetah 5.x the file extension has changed

type = 'neuralynx_dma';

manufacturer = 'Neuralynx';

content = 'raw aplifier data directly from DMA';

elseif isfolder(filename) && (any(filetype_check_extension({ls.name}, '.nev')) || any(filetype_check_extension({ls.name}, '.Nev')))

% a regular Neuralynx dataset directory that contains an event file

type = 'neuralynx_ds';

manufacturer = 'Neuralynx';

content = 'dataset';

elseif isfolder(filename) && most(filetype_check_extension({ls.name}, '.ncs'))

% a directory containing continuously sampled channels in Neuralynx format

type = 'neuralynx_ds';

manufacturer = 'Neuralynx';

content = 'continuously sampled channels';

elseif isfolder(filename) && most(filetype_check_extension({ls.name}, '.nse'))

% a directory containing spike waveforms in Neuralynx format

type = 'neuralynx_ds';

manufacturer = 'Neuralynx';

content = 'spike waveforms';

elseif isfolder(filename) && most(filetype_check_extension({ls.name}, '.nte'))

% a directory containing spike timestamps in Neuralynx format

type = 'neuralynx_ds';

manufacturer = 'Neuralynx';

content = 'spike timestamps';

elseif isfolder(filename) && most(filetype_check_extension({ls.name}, '.ntt'))

% a directory containing tetrode recordings in Neuralynx format

type = 'neuralynx_ds';

manufacturer = 'Neuralynx';

content = 'tetrode recordings ';

elseif filetype_check_extension(filename, '.mat') && contains(filename, 'times_')

type = 'wave_clus';

manufacturer = 'Department of Engineering, University of Leicester, UK';

content = 'sorted spikes';

elseif isfolder(p) && exist(fullfile(p, 'header'), 'file') && exist(fullfile(p, 'samples'), 'file') && exist(fullfile(p, 'events'), 'file')

type = 'fcdc_buffer_offline';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'FieldTrip buffer offline dataset';

elseif isfolder(filename) && exist(fullfile(filename, 'info.xml'), 'file') && exist(fullfile(filename, 'signal1.bin'), 'file')

% this is an OS X package directory representing a complete EEG dataset

% it contains a Content file, multiple xml files and one or more signalN.bin files

type = 'egi_mff';

manufacturer = 'Electrical Geodesics Incorporated';

content = 'raw EEG data';

elseif ~isfolder(filename) && isfolder(p) && exist(fullfile(p, 'info.xml'), 'file') && exist(fullfile(p, 'signal1.bin'), 'file')

% the file that the user specified is one of the files in an mff package directory

type = 'egi_mff';

manufacturer = 'Electrical Geodesics Incorporated';

content = 'raw EEG data';

% these are formally not Neuralynx file formats, but at the FCDC we use them together with Neuralynx

elseif isfolder(filename) && filetype_check_neuralynx_cds(filename)

% a downsampled Neuralynx DMA file can be split into three separate lfp/mua/spike directories

% treat them as one combined dataset

type = 'neuralynx_cds';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'dataset containing separate lfp/mua/spike directories';

elseif filetype_check_extension(filename, '.tsl') && filetype_check_header(filename, 'tsl')

type = 'neuralynx_tsl';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'timestamps from DMA log file';

elseif filetype_check_extension(filename, '.tsh') && filetype_check_header(filename, 'tsh')

type = 'neuralynx_tsh';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'timestamps from DMA log file';

elseif filetype_check_extension(filename, '.ttl') && filetype_check_header(filename, 'ttl')

type = 'neuralynx_ttl';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'Parallel_in from DMA log file';

elseif filetype_check_extension(filename, '.bin') && filetype_check_header(filename, {'uint8', 'uint16', 'uint32', 'int8', 'int16', 'int32', 'int64', 'float32', 'float64'})

type = 'neuralynx_bin';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'single channel continuous data';

elseif isfolder(filename) && any(filetype_check_extension({ls.name}, '.ttl')) && any(filetype_check_extension({ls.name}, '.tsl')) && any(filetype_check_extension({ls.name}, '.tsh'))

% a directory containing the split channels from a DMA logfile

type = 'neuralynx_sdma';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'split DMA log file';

elseif isfolder(filename) && filetype_check_extension(filename, '.sdma')

% a directory containing the split channels from a DMA logfile

type = 'neuralynx_sdma';

manufacturer = 'Donders Centre for Cognitive Neuroimaging';

content = 'split DMA log file';

% known Plexon file types

elseif filetype_check_extension(filename, '.nex') && filetype_check_header(filename, 'NEX1')

type = 'plexon_nex';

manufacturer = 'Plexon';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.plx') && filetype_check_header(filename, 'PLEX')

type = 'plexon_plx';

manufacturer = 'Plexon';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.ddt')

type = 'plexon_ddt';

manufacturer = 'Plexon';

elseif isfolder(filename) && most(filetype_check_extension({ls.name}, '.nex')) && most(filetype_check_header({ls.name}, 'NEX1'))

% a directory containing multiple plexon NEX files

type = 'plexon_ds';

manufacturer = 'Plexon';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.nex5') && filetype_check_header(filename, 'NEX5')

type = 'plexon_nex5';

manufacturer = 'Nex Technologies';

content = 'electrophysiological data';

% known Cambridge Electronic Design file types

elseif filetype_check_extension(filename, '.smr')

type = 'ced_son';

manufacturer = 'Cambridge Electronic Design';

content = 'Spike2 SON filing system';

% known BESA file types

elseif filetype_check_extension(filename, '.avr') && strcmp(type, 'unknown')

type = 'besa_avr'; % FIXME, can also be EEProbe average EEG

manufacturer = 'BESA';

content = 'average EEG';

elseif filetype_check_extension(filename, '.elp')

type = 'besa_elp';

manufacturer = 'BESA';

content = 'electrode positions';

elseif filetype_check_extension(filename, '.eps')

type = 'besa_eps';

manufacturer = 'BESA';

content = 'digitizer information';

elseif filetype_check_extension(filename, '.sfp')

type = 'besa_sfp';

manufacturer = 'BESA';

content = 'sensor positions';

elseif filetype_check_extension(filename, '.ela')

type = 'besa_ela';

manufacturer = 'BESA';

content = 'sensor information';

elseif filetype_check_extension(filename, '.pdg')

type = 'besa_pdg';

manufacturer = 'BESA';

content = 'paradigm file';

elseif filetype_check_extension(filename, '.tfc')

type = 'besa_tfc';

manufacturer = 'BESA';

content = 'time frequency coherence';

elseif filetype_check_extension(filename, '.mul')

type = 'besa_mul';

manufacturer = 'BESA';

content = 'multiplexed ascii format';

elseif filetype_check_extension(filename, '.dat') && filetype_check_header(filename, 'BESA_SA') % header can start with BESA_SA_IMAGE or BESA_SA_MN_IMAGE

type = 'besa_src';

manufacturer = 'BESA';

content = 'beamformer source reconstruction';

elseif filetype_check_extension(filename, '.swf') && filetype_check_header(filename, 'Npts=')

type = 'besa_swf';

manufacturer = 'BESA';

content = 'beamformer source waveform';

elseif filetype_check_extension(filename, '.bsa')

type = 'besa_bsa';

manufacturer = 'BESA';

content = 'beamformer source locations and orientations';

elseif exist(fullfile(p, [f '.dat']), 'file') && (exist(fullfile(p, [f '.gen']), 'file') || exist(fullfile(p, [f '.generic']), 'file'))

type = 'besa_sb';

manufacturer = 'BESA';

content = 'simple binary channel data with a separate generic ascii header';

elseif filetype_check_extension(filename, '.sfh') && filetype_check_header(filename, 'NrOfPoints')

type = 'besa_sfh';

manufacturer = 'BESA';

content = 'electrode and fiducial information';

elseif filetype_check_extension(filename, '.besa')

type = 'besa_besa';

manufacturer = 'BESA';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.srf') && filetype_check_header(filename, [0 0 0 0], 4)

type = 'brainvoyager_srf';

manufacturer = 'BrainVoyager'; % see http://support.brainvoyager.com/installation-introduction/23-file-formats/375-users-guide-23-the-format-of-srf-files.html

content = 'surface';

% known Dataq file formats

elseif filetype_check_extension(upper(filename), '.WDQ')

type = 'dataq_wdq';

manufacturer = 'dataq instruments';

content = 'electrophysiological data';

% old files from Pascal Fries' PhD research at the MPI

elseif filetype_check_extension(filename, '.dap') && filetype_check_header(filename, char(1))

type = 'mpi_dap';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

elseif isfolder(filename) && ~isempty(cell2mat(regexp({ls.name}, '.dap$')))

type = 'mpi_ds';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

% Frankfurt SPASS format, which uses the Labview Datalog (DTLG) format

elseif filetype_check_extension(filename, '.ana') && filetype_check_header(filename, 'DTLG')

type = 'spass_ana';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.swa') && filetype_check_header(filename, 'DTLG')

type = 'spass_swa';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.spi') && filetype_check_header(filename, 'DTLG')

type = 'spass_spi';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.stm') && filetype_check_header(filename, 'DTLG')

type = 'spass_stm';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

elseif filetype_check_extension(filename, '.bhv') && filetype_check_header(filename, 'DTLG')

type = 'spass_bhv';

manufacturer = 'MPI Frankfurt';

content = 'electrophysiological data';

% known Chieti ITAB file types

elseif filetype_check_extension(filename, '.raw') && (filetype_check_header(filename, 'FORMAT: ATB-BIOMAGDATA') || filetype_check_header(filename, '[HeaderType]'))

type = 'itab_raw';

manufacturer = 'Chieti ITAB';

content = 'MEG data, including sensor positions';

elseif filetype_check_extension(filename, '.raw.mhd')

type = 'itab_mhd';

manufacturer = 'Chieti ITAB';

content = 'MEG header data, including sensor positions';

elseif filetype_check_extension(filename, '.asc') && ~filetype_check_header(filename, '**')

type = 'itab_asc';

manufacturer = 'Chieti ITAB';

content = 'headshape digitization file';

% known Nexstim file types

elseif filetype_check_extension(filename, '.nxe')

type = 'nexstim_nxe';

manufacturer = 'Nexstim';

content = 'electrophysiological data';

% known Tucker-Davis-Technology file types

elseif filetype_check_extension(filename, '.tbk')

type = 'tdt_tbk';

manufacturer = 'Tucker-Davis-Technology';

content = 'database/tank meta-information';

elseif filetype_check_extension(filename, '.tdx')

type = 'tdt_tdx';

manufacturer = 'Tucker-Davis-Technology';

content = 'database/tank meta-information';

elseif filetype_check_extension(filename, '.tsq')

type = 'tdt_tsq';

manufacturer = 'Tucker-Davis-Technology';

content = 'block header information';

elseif filetype_check_extension(filename, '.tev')

type = 'tdt_tev';

manufacturer = 'Tucker-Davis-Technology';

content = 'electrophysiological data';

% raw audio and video data from https://github.com/andreyzhd/VideoMEG

% the extension *.aud/*.vid is used at NatMEG and *.audio.dat/*.video.dat seems to be used in Helsinki

elseif (filetype_check_extension(filename, '.aud') || filetype_check_extension(filename, '.audio.dat')) && filetype_check_header(filename, 'ELEKTA_AUDIO_FILE')

% this should go before curry_dat

type = 'videomeg_aud';

manufacturer = 'VideoMEG';

content = 'audio';

elseif (filetype_check_extension(filename, '.vid') || filetype_check_extension(filename, '.video.dat')) && filetype_check_header(filename, 'ELEKTA_VIDEO_FILE')

% this should go before curry_dat

type = 'videomeg_vid';

manufacturer = 'VideoMEG';

content = 'video';

elseif (filetype_check_extension(filename, '.avi') || filetype_check_extension(filename, '.vlf') || filetype_check_extension(filename, '.wmv') || filetype_check_extension(filename, '.mov') || filetype_check_extension(filename, '.mp4'))

% generic fideo files, these are also supported by ft_read_header and ft_read_data

type = 'video';

manufacturer = 'generic';

content = 'video';

elseif (filetype_check_extension(filename, '.dat') || filetype_check_extension(filename, '.Dat')) && (exist(fullfile(p, [f '.ini']), 'file') || exist(fullfile(p, [f '.Ini']), 'file'))

% this should go before curry_dat

type = 'deymed_dat';

manufacturer = 'Deymed';

content = 'raw eeg data';

elseif (filetype_check_extension(filename, '.ini') || filetype_check_extension(filename, '.Ini')) && (exist(fullfile(p, [f '.dat']), 'file') || exist(fullfile(p, [f '.Dat']), 'file'))

type = 'deymed_ini';

manufacturer = 'Deymed';

content = 'eeg header information';

elseif filetype_check_extension(filename, '.dat') && (filetype_check_header(filename, [0 0 16 0 16 0], 8) || filetype_check_header(filename, [0 0 16 0 16 0], 0))

% this should go before curry_dat

type = 'jaga16';

manufacturer = 'Jinga-Hi';

content = 'electrophysiological data';

% some AnyWave file formats, see http://meg.univ-amu.fr/wiki/AnyWave:ADES

elseif filetype_check_extension(filename, '.ades') && filetype_check_header(filename, '#ADES') && exist(fullfile(p, [f '.dat']), 'file')

type = 'anywave_ades';

manufacturer = 'AnyWave';

content = 'continuous EEG, iEEG or MEG data';

elseif filetype_check_extension(filename, '.dat') && exist(fullfile(p, [f '.ades']), 'file') && filetype_check_header(fullfile(p, [f '.ades']), '#ADES')

% this should go before curry_dat

type = 'anywave_dat';

manufacturer = 'AnyWave';

content = 'continuous EEG, iEEG or MEG data';

% known Curry V4 file types

elseif filetype_check_extension(filename, '.dap')

type = 'curry_dap'; % FIXME, can also be MPI Frankfurt electrophysiological data

manufacturer = 'Curry';

content = 'data parameter file';

elseif filetype_check_extension(filename, '.dat')

type = 'curry_dat';

manufacturer = 'Curry';

content = 'raw data file';

elseif filetype_check_extension(filename, '.rs4')

type = 'curry_rs4';

manufacturer = 'Curry';

content = 'sensor geometry file';

elseif filetype_check_extension(filename, '.par')

type = 'curry_par';

manufacturer = 'Curry';

content = 'data or image parameter file';

elseif filetype_check_extension(filename, '.bd0') || filetype_check_extension(filename, '.bd1') || filetype_check_extension(filename, '.bd2') || filetype_check_extension(filename, '.bd3') || filetype_check_extension(filename, '.bd4') || filetype_check_extension(filename, '.bd5') || filetype_check_extension(filename, '.bd6') || filetype_check_extension(filename, '.bd7') || filetype_check_extension(filename, '.bd8') || filetype_check_extension(filename, '.bd9')

type = 'curry_bd';

manufacturer = 'Curry';

content = 'BEM description file';

elseif filetype_check_extension(filename, '.bt0') || filetype_check_extension(filename, '.bt1') || filetype_check_extension(filename, '.bt2') || filetype_check_extension(filename, '.bt3') || filetype_check_extension(filename, '.bt4') || filetype_check_extension(filename, '.bt5') || filetype_check_extension(filename, '.bt6') || filetype_check_extension(filename, '.bt7') || filetype_check_extension(filename, '.bt8') || filetype_check_extension(filename, '.bt9')

type = 'curry_bt';

manufacturer = 'Curry';

content = 'BEM transfer matrix file';

elseif filetype_check_extension(filename, '.bm0') || filetype_check_extension(filename, '.bm1') || filetype_check_extension(filename, '.bm2') || filetype_check_extension(filename, '.bm3') || filetype_check_extension(filename, '.bm4') || filetype_check_extension(filename, '.bm5') || filetype_check_extension(filename, '.bm6') || filetype_check_extension(filename, '.bm7') || filetype_check_extension(filename, '.bm8') || filetype_check_extension(filename, '.bm9')

type = 'curry_bm';

manufacturer = 'Curry';

content = 'BEM full matrix file';

elseif filetype_check_extension(filename, '.dig')

type = 'curry_dig';

manufacturer = 'Curry';

content = 'digitizer file';

elseif filetype_check_extension(filename, '.cdt')

type = 'curry_cdt';

manufacturer = 'Curry';

content = 'Curry8 data file';

elseif filetype_check_extension(filename, '.cef')

type = 'curry_cef';

manufacturer = 'Curry';

content = 'Curry event file';

elseif filetype_check_extension(filename, '.dpa')

type = 'curry_dpa';