EBS – Extensible bio-signal file format
Markus Kuhn
EBS is a simple binary file format for storing multi-channel
time-series recordings and associated metadata. I wrote its
specification in 1993 while I worked in the group of Prof. Manfred
Spreng at the Institute for
Physiology at the University
of Erlangen, Germany. We used EBS primarily for handling EEG, MEG,
and ECoG recordings from human brains. EBS is a simple general-purpose
format that is also well suited for numerous other types of biomedical
multi-channel time-series signals.
The web
site of the research group in which we created EBS originally no
longer seems to exist. As there is continued interest in and use of EBS,
I have put together this web page to collect related information
and links.
Even though I have not been actively involved with processing
bio-signal data for a number of years, as the original principal
designer of EBS, I am happy to help EBS users with answering questions
where I can. I am still maintaining the standard and the associated
registry of tag-number ranges assigned to individual users, and I am
happy to receive suggestions for its improvement.
Quick overview of EBS
The EBS file format
- can store zero, one, or more data channels (up to 232);
- currently supports as numeric types for samples
- 16-bit signed integers (both Bigendian and Litteendian),
- delta-encoded 16-bit signed integers
(1 byte/sample if
difference to preceeding sample is within {−127, ..., +127},
3 bytes/sample otherwise, which saves often nearly 50% space);
- allows data samples to be arranged in the file
- by time (more convenient for recording equipment),
- by channel (more efficient for applications that want to read only
one stored channel at a time);
- requires that all channels share the same data encoding, sampling
frequency and length;
- is designed for handling very large data sets (up to
264 samples and 266 bytes);
- permits in-place changes, additions and deletions of metadata,
without any need for copying the whole file;
- supports real-time read access while data is still being recorded.
- supports metadata attributes for the entire recording including
- patient's or subject's name, identifier, date of birth, sex,
- short single-line summary description of recording,
- multi-line detailed description text,
- sampling rate,
- institution,
- processing history (sequence of multi-line strings),
- location diagram (e.g., for marking electrode positions) stored as
simple CGM vector graphics,
- event markers (grouped, with description strings, per channel or
recording),
- recording date and time;
- supports metadata attributes per channel including
- preferred integer range (as a hint for display software),
- unit and scale factor,
- description,
- channel group,
- corresponding coordinate in location diagram,
- preprocessing filter parameters;
- supports Unicode strings in attributes;
- has provisions for backwards-compatible future standardized and
proprietary extensions of the format.
More information on EBS
Publications
- Markus G. Kuhn, Markus Prosch: Vorschlag für ein Dateiformat für
die Verarbeitung, die Archivierung und den Austausch von
Biosignal-Daten, in: R.G. Müller, J. Erb:
Medizinische Physik 1993, 24. Wissenschaftliche Tagung
der Deutschen Gesellschaft für Medizinische Physik e.V.,
Tagungsband, S. 116f, Erlangen, Oktober 1993.
- Gunther Hellman, Markus G. Kuhn, Markus Prosch, Manfred Spreng:
Extensible
biosignal (EBS) file format: simple method for EEG data
exchange, Electroencephalography and Clinical
Neurophysiology, Vol. 99, No. 5, November 1996, Elsevier Science,
pp. 426–431.
- G. Hellmann, M. Prosch, M. Spreng: 3 years experience with an
extensible biosignal (EBS) file format for data exchange. In:
Witte, H.; Zwiener, U. (Hrsg.) Quantitative and Topological EEG
and MEG Analysis. Universitätsverlag Druckhaus Mayer, Jena, 1997.
More information to come (please feel free to ask) ...