EDF data format.

The EDF format is a simple and flexible format for the storage and exchange of multichannel biological signals. The data consists of a header record and then all of the data records from the beginning to the end of the recording. The header consists of two records.

  • The first record of 256 bytes specifies the version of the data, patient information, time information of the record, the number of data records and the number of signals in each data record.
  • Then there follows a record whose length depends on the number of signals in the recording. For every channel 256 bytes are needed. This record contains information about the type of signal, amplitude, calibration and the number of samples in the data record.

 

Header Record (first part)

The first part of the header record is build-up as follow.

number of bytes
field type
description
format
8
ascii
Version of the data format (for EDF is that 0)
-
80
ascii
Local Patient identification
-
80
ascii
Local recording identification
-
8
ascii
Start date of the recording
dd.mm.yy
8
ascii
Start time of the recording
hh.mm.ss
8
ascii
Number of bytes for the header record
-
44
ascii
Reserved
-
8
ascii
Number of data records (-1 if it is unknown)
-
8
ascii
recording time of the datarecord
in seconds
4
ascii
number of signals in a data record (ns)
-
The first part of the header contains 256 bytes

Header Record (second part)

The second part of the header record is build-up as follow.

number of bytes
field type
description
format
ns * 16
ascii
Signal lable. (e.g. EEG FpzCz, Body temp or EDF Annotations)
-
ns * 80
ascii
Transductor type ( e.g. AgAgCi electrode)
-
ns * 8
ascii
Physical dimention (e.g. µV or degreeC)
-
ns * 8
ascii
Physical minimum (e.g. -500 or 34)
-
ns * 8
ascii
Physical maximum (e.g. 500 or 40)
-
ns * 8
ascii
Digital minimum (e.g. -2048)
-
ns * 8
ascii
Digital maximum (e.g. 2047)
-
ns * 80
ascii
Prefiltering (e.g. HP:0.1Hz LP:75Hz)
-
ns * 8
ascii
Number of samples (nr) in each data record
-
ns *32
ascii
reserved.
-
The second part of the header contains (ns) * 256 bytes

The data record.

A data record consists of the data samples of each channel where all data samples of channel 1 consecutive be saved. Then comes channel 2 ... until all channels are stored. This record will be followed by another new record of the specified data recording time.

For all programs and source code:

© 2008 by BRAINTRONICS. All rights reserved.

 

Disclaimer:
 
THE PROGRAM AND ANY SUPPORT IS PROVIDED BY BRAINTRONICS "AS IS" WITHOUT WARRANTY OR CONDITION OF ANY KIND EITHER EXPRESS, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND/OR NON-INFRINGEMENT. THE ENTIRE RISK ARISING OUT OF THE USE OR PERFORMANCE OF THE PROGRAM AND SUPPORT REMAINS WITH YOU. IN NO EVENT WILL BRAINTRONICS BE LIABLE FOR ANY LOST PROFITS, LOST SAVINGS, LOST REVENUE, LOST DATA OR FOR ANY DIRECT, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF BRAINTRONICS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES OR DAMAGES. IN ADDITION BRAINTRONICS WILL NOT BE LIABLE FOR ANY DAMAGES CLAIMED BY YOU BASED ON ANY THIRD PARTY CLAIM.

Braintronics address