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BrainVision Import ​

This demo demonstrates importing BrainVision format files into EegFun.jl.

What is BrainVision Format? ​

BrainVision is the data format used by Brain Products GmbH EEG systems (e.g., BrainAmp, actiCHamp, LiveAmp). It's a flexible, text-header based format widely used in research.

The format consists of three files:

  • .vhdr - Header file (ASCII text) containing metadata, channel information, and data format specifications

  • .eeg - Binary data file containing the actual EEG samples

  • .vmrk - Marker file (ASCII text) with trigger/event information

Key features:

  • Human-readable header and marker files

  • Flexible data encoding (16-bit, 32-bit integer or float)

  • Separate marker file for triggers and annotations

  • Wide support across analysis platforms

Import Capabilities ​

Data loading:

  • Raw continuous EEG time series

  • Sampling rate and channel metadata

  • Trigger/event markers with descriptions

What you need:

  • BrainVision triplet (.vhdr, .eeg, .vmrk files in same directory)

  • Electrode layout file matching your cap configuration

  • Brain Products systems often use actiCap or EasyCap layouts

Data Mapping ​

EegFun.read_raw_data loads BrainVision data, then create_eegfun_data converts to native EegFun types:

  • BrainVision → BrainVisionData (intermediate) → ContinuousData (EegFun)

  • Markers extracted from .vmrk file

  • Layout coordinates added separately

Important Notes ​

File Organization ​

All three files must be in the same directory with matching base names:

text
my_recording.vhdr
my_recording.eeg
my_recording.vmrk

You can specify any of the three files to read_raw_data() - it will automatically find the others.

Layout Files ​

BrainVision doesn't embed 3D electrode positions, so you must provide a matching layout. Depending on your cap manufacturer:

Brain Products actiCap: Check resources/layouts/acticap/ EasyCap: Check resources/layouts/easycap/

Choose the layout matching your recording configuration.

Marker Types ​

BrainVision supports rich marker information including:

  • Stimulus markers (trigger codes)

  • Response markers (button presses)

  • Comments and annotations

  • Segment boundaries

EegFun imports all markers and makes them available for epoch extraction and analysis.

Workflow Summary ​

This demo shows the complete BrainVision import workflow:

Load Raw BrainVision Data ​

  • Use read_raw_data() with path to any file in the triplet (.vhdr, .eeg, or .vmrk)

  • Automatic format detection based on file extension

  • All three files loaded automatically

Prepare Layout ​

  • Load appropriate layout file for your cap configuration

  • Convert polar coordinates to cartesian for visualization

Create EegFun Data Structure ​

  • Combine raw data with layout using create_eegfun_data()

  • Results in ContinuousData ready for analysis

Code Examples ​

Show Code
julia
# Demo: Loading and Processing BrainVision Files
# Shows how to load BrainVision format files (.vhdr, .eeg, .vmrk),
# create EegFun data structures, apply basic preprocessing,
# and get the triggers/events.

# Note: EegFun.example_path() resolves bundled example data paths.
# When using your own data, simply pass the file path directly, e.g.:
# dat = EegFun.read_raw_data("/path/to/your/data.vhdr")

using EegFun
using GLMakie

# Load raw BrainVision data
# read_raw_data automatically detects BrainVision files (.vhdr, .eeg, or .vmrk)
# You can specify any of the three files; it will find the others, assuming 
# they are in the same directory
dat = EegFun.read_raw_data(EegFun.example_path("data/brainvision/example1.vhdr"))

# EegFun uses the Julia package: BrainVisionDataFormat.jl
# https://github.com/igmmgi/BrainVisionDataFormat.jl
dat.data
dat.header

# Create EegFun data structure
eeg = EegFun.create_eegfun_data(dat)

EegFun.all_data(eeg)
EegFun.meta_data(eeg)
EegFun.all_labels(eeg)
EegFun.channel_labels(eeg)
EegFun.meta_labels(eeg)
EegFun.extra_labels(eeg)

# Check trigger information
# EegFun creates a hash of the marker names for the numeric trigger column
# triggers_info contains the mapping of trigger names to numeric values
println("\nTrigger summary:")
EegFun.trigger_count(eeg)

# Basic preprocessing
EegFun.highpass_filter!(eeg, 1.0) # 1 Hz high-pass
EegFun.rereference!(eeg, :avg)    # Average reference

# Open interactive databrowser
EegFun.plot_databrowser(eeg);

See Also ​