Name

Synopsis

Description

a2m

Use a2m to convert AHA-format annotation files into MIT format. Options for a2m include:

-s time

Shift annotations forward by the specified time (default: no shift for type 0 input files, 5 minutes for type 1, 2 hours and 30 minutes for type 2; for type 3, the default is 5 minutes if record is of the form n2nn or n3nn, or 2 hours and 30 minutes if record is of the form n0nn or n1nn).

-t type

Convert an input file of the specified type (0: a file produced by a WFDB application using putann and WFDB_AHA_WRITE mode; 1: an AHA DB ‘short format’ tape file; 2: an AHA DB ‘long format’ tape file; 3: an AHA DB compressed (.ano) CD-ROM or floppy disk file). Input files of types 1, 2, and 3 are assumed to contain annotation times in milliseconds, which are converted to sampling intervals based on an assumed sampling frequency of 250 Hz. Default: type 3 is assumed if ahafile ends with .ANO or .ano; type 0 is assumed otherwise.

ad2m

Use ad2m to convert AHA-format signal files into MIT format. Options for ad2m include:

-c

Convert an AHA DB compressed (.cmp) floppy disk file (this is the default if ahafile ends with .CMP or .cmp, otherwise ad2m assumes that the input is a file in AHA DB tape format).

-f time

Begin converting at the specified time relative to the beginning of the input file (default: 0, i.e., at the beginning of the input file)

-t time

Stop converting at the specified time relative to the beginning of the input file (default: 35 minutes after the starting time if record is of the form n2nn or n3nn, 3 hours if record is of the form n0nn or n1nn, or the end of the input file, whichever comes first).

ahaconvert

Use ahaconvert to convert one or more records from an AHA DB CD-ROM into MIT format. Run ahaconvert without any command-line arguments for instructions, or see the examples below. Note: ahaconvert is a shell script; to use it successfully, you will need to have a shell (standard with all versions of Unix, and included in the free Cygwin package for MS-Windows) as well as ad2m and a2m, which perform the actual work of the conversion.

m2a

Use m2a to convert MIT-format annotation files into AHA tape format. Options for m2a include:

-s time

Shift annotation times backward by the specified time, and convert them from sample intervals to milliseconds.

md2a

Use md2a to convert MIT-format signal files into AHA tape format. Options for md2a include:

-n new-record

Create a new header file for the AHA-format output signal file, so that it may be read as record new-record.

MIT-format files can be excerpted and reformatted in more generally useful ways using snip(1) or xform(1) .

Environment

It may be necessary to set and export the shell variable WFDB (see setwfdb(1) ).

Examples

AHA Database CD-ROM

To convert the long-format records only, type:
   ahaconvert /mnt/cdrom/?[01]??.cmp

AHA DB floppy disk

AHA DB short format tape

To obtain the same files given a ‘short format’ 9-track distribution tape, copy the second and third files from the tape into files 1201.tap and 1201.ann in the current directory, then type:
   ad2m -i 1201.tap -r 1201

   a2m -i 1201.ann -r 1201 -a atr -t 1

The names for the files copied from the tape are arbitrary, but do not use names of files to be generated by ad2m or a2m (see the previous example). Note that the first and fourth files on the distribution tape contain an ‘id’ block, which can be read by readid (a program included in the convert directory of the WFDB Software Package) to verify the record name. Distribution tapes that contain more than one record contain additional sets of four files, always in the same order within each set.

AHA DB long format tape

To make a version of the three-hour AHA DB record 1001 in MIT format, given the ‘long format’ distribution tape, copy the second and third files from the tape into files 1001.tap and 1001.ann in the current directory, then type:
   ad2m -i 1001.tap -r 1001 -t 3:0:0

   a2m -i 1001.ann -r 1001 -a atr -t 2

The -t 3:0:0 option is necessary to prevent ad2m from truncating the signal file after the first 35 minutes.

Converting AHA DB long format to short format

To make a version of AHA DB record 1201 in MIT format, given a ‘long format’ 9-track distribution tape containing the corresponding three-hour record 1001, copy the second and third files from the tape into files 1001.tap and 1001.ann in the current directory, then type:
   ad2m -i 1001.tap -r 1201 -f 2:25:0

   a2m -i 1001.ann -r 1201 -a atr -t 1

In this case, the -f option instructs ad2m to skip the first two hours and 25 minutes of the ‘long-format’ AHA signal file, and to reformat the remainder (equivalent to the 35-minute ‘short-format’ record). The -t 1 option is used with a2m even though its input file comes from a ‘long-format’ tape, because the annotation times must be shifted only by the amount necessary for a ‘short-format’ tape in this case.

Sharing signal files for long format and short format AHA DB records

To keep both versions (1001 and 1201) on-line, make the ‘long format’ version first (see above), then type:
   a2m -i 1001.ann -r 1201 -a atr -t 1

to make a ‘short format’ reference annotation file. Continue (under UNIX) by:
   cp 1001.hea 1201.hea

or (under MS-DOS) by:
   copy 1001.hea 1201.hea

and edit 1201.hea, replacing ‘1001’ in the first line (only!) with ‘1201’, and replacing ‘212’ in the second and third lines by ‘212+6525000’ (see the description of the ‘byte offset’ field in header(5) ). Although two header and reference annotation files are needed, both versions can share the same signal file, allowing a substantial savings in storage requirements. Note that WFDB application programs that read the ‘short format’ record 1201 signal file may report signal checksum errors at the end of the record, unless you also recalculate the signal checksums (easily done using snip(1) to copy the record; delete the copy once the checksums have been obtained).

Availability

See Also

Author

Sources

Table of Contents

• Name
• Synopsis
• Description
• a2m
• ad2m
• ahaconvert
• m2a
• md2a
• Environment
• Examples
• AHA Database CD-ROM
• AHA DB floppy disk
• AHA DB short format tape
• AHA DB long format tape
• Converting AHA DB long format to short format
• Sharing signal files for long format and short format AHA DB records
• Availability
• See Also
• Author
• Sources

Up: WFDB Applications Guide

Updated 6 February 2008