Data Files
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2016-2017 SR Research Ltd.
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version of the converter is bundled with the EyeLink Developers Kit for Mac
(
https://www.sr-support.com/showthread.php?15
).
EyeLink Data Viewer is an optional tool that allows displaying, filtering, and
reporting the output of EyeLink Data Files. Please check EyeLink Data Viewer
User’s Manual for details.
4.8 Using ASC Files
The EDF file format is an efficient storage format for eye movement data, but is
relatively complex for third-party data analysis applications to work with. To
make the data in EDF files accessible, the translator EDF2ASC converts the
files into a text version that is easily accessible from almost any programming
language. The converted ASC files contain lines of text, with each line
containing data for a single sample, event or data parameter.
The EDF2ASC utility reads one or more EDF files, creating text files with the
same name but with the ASC extension. It scans the input file, reordering data
as required, and converting samples and events into lines of text. It can also
compute resolutions and instantaneous velocity for sample data. An ASC file
will generally be about twice as large as the original EDF file.
EDF2ASC converter utility can be run from the GUI interface assuming that
you have installed the EyeLink Data Viewer software. Users can also run the
EDF2ASC converter from the DOS command line prompt, assuming that
Windows Display Software has been installed. To translate an EDF file from the
command line prompt, type "edf2asc" followed by the name of the file to be
translated and any conversion options. Wildcards (* and ?) may be used in the
input file name, allowing conversion of multiple EDF files to ASC files with the
same name. Optionally, a second file name can be specified for the output ASC
file. Many options exist for the file conversion. One set of options will be best for
your work, and creation of a single-line batch file (called, for example, E2A.BAT)
will make the use of the translator easier. The following table lists commonly-
used options.
-l or -nr
outputs left-eye data only if binocular data file
-r or -nl
outputs right-eye data only if binocular data file
-sp
outputs sample raw pupil position if present
-sh
outputs sample HREF angle data if present
-sg
outputs sample GAZE data if present (default)
-res
outputs resolution data if present
-vel
outputs velocity data in samples if possible
-s or -ne
outputs sample data only
-e or -ns
outputs event data only
-nse
blocks output of start events
-nmsg
blocks message event output
-neye
outputs only non-eye events (for sample-only
files)
