.TH EDF2MIT 1 "28 October 2009" "WFDB 10.4.24" "WFDB Applications Guide"
.SH NAME
edf2mit, mit2edf \- convert between EDF and WFDB-compatible formats
.SH SYNOPSIS
\fBedf2mit -i\fR \fIedffile\fR [ \fIoptions\fR ... ]
.br
\fBmit2edf -r\fR \fIrecord\fR [ \fIoptions\fR ... ]
.SH DESCRIPTION
.PP
These programs convert EDF (European Data Format) files into
WFDB-compatible files (as used in PhysioBank) and vice versa. European
Data Format was originally designed for storage of polysomnograms.
.PP
\fBedf2mit\fR reads the specified \fIedffile\fR and creates WFDB-compatible
signal and header files containing the same data. Options for
\fBedf2mit\fR include:
.TP
\fB-b\fR
Input is in big-endian byte order (default: little-endian).
.TP
\fB-h\fR
Print a brief usage summary.
.TP
\fB-r\fR \fIrecord\fR
Create the specified \fIrecord\fR (default: use the patient ID field from
the input file as the record name).
.TP
\fB-s\fR \fIsignal-list\fR
Copy only the signals named in the \fIsignal-list\fR (one or more input signal
numbers, separated by spaces; default: copy all signals). Signals are
numbered consecutively beginning with zero. This option may be used to
re-order or duplicate signals.
.TP
\fB-v\fR
Verbose mode (print debugging output).
.PP
\fBmit2edf\fR reads the specified WFDB-format \fIrecord\fR (header and signal
files) and creates an EDF file containing the same data. Output from
\fBmit2edf\fR is always in the standard little-endian format. Options for
\fBmit2edf\fR include:
.TP
\fB-h\fR
Print a brief usage summary.
.TP
\fB-o\fR \fIfile\fR
Write output to the specified \fIfile\fR (default: \fIrecord\fR\fB.edf\fR).
.TP
\fB-v\fR
Verbose mode (print debugging output).
.PP
Note that WFDB format does not include a standard way to specify the
transducer type or the prefiltering specification; these parameters are
not preserved by these conversion programs. Also note that use of the standard
signal and unit names specified for EDF is permitted but not enforced by
\fBmit2edf\fR.
.PP
Many EDF files contain signals at widely varying sampling frequencies.
\fBedf2mit\fR handles these properly, but the default behavior of most
WFDB applications is to read such data in low-resolution mode (in which
all signals are resampled at the lowest sampling frequency used for any
signal in the record). This is almost certainly not what you want if, for
example, the record contains EEG signals sampled at 200 Hz and body temperature
sampled at 1 Hz; by default, applications such as \fBrdsamp\fR and \fBwave\fR
will resample the EEGs (and any other signals in the record) at 1 Hz. To
avoid this behavior, you can use the \fB-H\fR (high resolution) option provided
by \fBrdsamp\fR, \fBwave\fR, and a few other WFDB applications, or you can
set the environment variable \fBWFDBGVMODE\fR to 1 (or any non-zero value) to
specify that signals are to be read in high-resolution mode (in which all
signals are resampled at the highest frequency used for any signal in the
record). Setting \fBWFDBGVMODE\fR works with all WFDB applications, not only
those that support the \fB-H\fR option. For further information, see the
section titled "Multi-Frequency Records" in chapter 5 of
the \fIWFDB Programmer's Guide\fR.
.PP
Note that applications built using version 10.4.5 and later versions of the
WFDB library can read EDF files directly, so that the conversion performed
by \fBedf2mit\fR is no longer necessary. The native WFDB files produced by
\fBedf2mit\fR can be read more efficiently and with lower latency and memory
requirements than the EDF files; in most cases, however, the difference
will not be noticeable.
.SH ENVIRONMENT
.PP
It may be necessary to set and export the shell variable \fBWFDB\fR (see
\fBsetwfdb\fR(1)).
.SH AVAILABILITY
These programs are provided in the \fIconvert\fR directory of the WFDB Software
Package. Run \fBmake\fR in that directory to compile and install them if they
have not been installed already.
.PP
The PhysioNet ATM (http://physionet.org/cgi-bin/ATM) provides web access to
\fBmit2edf\fR (select \fBExport signals as EDF\fR from the Toolbox).
.SH SEE ALSO
\fBa2m\fR(1), \fBrdedfann\fR(1), \fBsnip\fR(1), \fBxform\fR(1), \fBwfdb\fR(3),
\fBheader\fR(5)
.HP
Bob Kemp, Alpo V\[:a]rri, Agostinho C. Rosa, Kim D. Nielsen and John Gade.
A simple format for exchange of digitized polygraphic recordings.
\fIElectroencephalography and Clinical Neurophysiology\fB 82\fR:391-393 (1992).
.HP
Bob Kemp's EDF web site (http://www.edfplus.info/).
The definitive reference on the format; it includes the full specification of
EDF from the 1992 paper, sample EDF files, software for reading and viewing
them, FAQs, and much more.
.SH AUTHOR
George B. Moody (george@mit.edu)
.SH SOURCES
http://www.physionet.org/physiotools/wfdb/convert/edf2mit.c
.br
http://www.physionet.org/physiotools/wfdb/convert/mit2edf.c