Biosignal file formats
EDF vs BDF: practical differences for waveform review.
EDF and BDF are related recording formats, while the “plus” variants add interoperable annotation capabilities and rules. The file extension alone is not enough to judge content quality or suitability.
Compare the format families
| Format | Signal sample storage | Annotation model | Practical review note |
|---|---|---|---|
| EDF | Signed 16-bit digital samples | No EDF+ annotation channel | Check header fields, channel scaling, units, and sample rates. |
| EDF+ | Signed 16-bit digital samples | EDF Annotations signal | May carry time-stamped events and support continuous or discontinuous recordings. |
| BDF | Signed 24-bit digital samples | No BDF+ annotation channel | Commonly associated with BioSemi recordings; status/trigger content requires appropriate interpretation. |
| BDF+ | Signed 24-bit digital samples | BDF Annotations signal | Extends the related plus conventions to BDF recordings. |
Both families use a main recording header, per-signal header fields, and data records. Channels can use different samples-per-record values. Software must apply each channel’s digital and physical ranges correctly to present physical values.
For normative details, consult the EDF/EDF+ specifications and BioSemi’s BDF file-format description. This page is an orientation for reviewers, not a replacement for either specification.
What changes in the review workflow?
The first checks stay the same: identify the format, confirm recording and channel metadata, examine units and sample rates, and establish the time base. For plus files, also inspect annotation provenance, onset, duration, and text.
Do not infer that BDF is “better” simply because it uses wider digital samples. Acquisition hardware, scaling, signal quality, headers, annotations, and the intended analysis all matter. Likewise, the plus suffix does not certify that every annotation is complete or clinically meaningful.
Current EDF Workbench behavior
The Windows preview opens EDF, EDF+, BDF, and BDF+ within documented limits. Supported recording annotations are read-only. User-created annotations are stored separately. Display downsampling may use an extrema-preserving envelope, while measurements and exports follow their documented source-sample paths.
The preview does not claim universal vendor compatibility, format repair, automated diagnosis, or conversion between EDF and BDF. If a malformed or unsupported recording is rejected, preserve the original and use the application’s recovery information without publishing sensitive paths or content.
Open all four supported families
Review the current Windows preview and its documented limits.
The Download page records the exact release, architecture, signature, and checksum.