dmedine / xdf-matlab

Matlab code for working with xdf files.

Overview

This is a MATLAB importer for .xdf files. xdf files are likely to have been created by LabRecorder, the default file recorder for use with LabStreamingLayer. LabRecorder records a collection of streams, including all their data (time-series / markers, meta-data) into a single XDF file. The XDF format (Extensible Data Format) is a general-purpose format for time series and their meta-data that was jointly developed with LSL to ensure compatibility, see here.

Usage

After a session has been recorded to disk using the LabRecorder or any other compatible recording application, it can be imported into MATLAB using the functions in this folder.

Note that EEGLAB plugins are structured so the EEGLAB (/BCILAB/MoBILAB) plugin files are in the top level (i.e. the directory containing this readme) and the actual import function is load_xdf in the xdf subfolder.

To use load_xdf directly:

• Start MATLAB and make sure that you have the function added to MATLAB's path. You can do this either through the GUI, under File / Set Path / Add Folder) or in the command line, by typing:

addpath('C:\\path\\to\\xdf_repo\\Matlab\\xdf')

• To load an .xdf file, type in the command line:

streams = load_xdf('your_file_name.xdf')

• After a few seconds it should return a cell array with one cell for every stream that was contained in the file. For each stream you get a struct that contains the entire meta-data (including channel descriptions and domain-specific information), as well as the time series data itself (numeric or cell-string array, depending on the value type of the stream), and the time stamps of each sample in the time series. All time stamps (across all streams, even if they were collected on different computers of the lab network) are in the same time domain, so they are synchronized. Note that time stamps from different .xdf files are generally not synchronized (although they will normally be in seconds since the recording machine was turned on).

Documentation

As usual in MATLAB, to get the documentation of the function, type help load_xdf or doc load_xdf.