Skip to main content

BrainVisionReader

Namespace: BIDSLIB  ·  Library: BIDS Library

#include <bids/bids_brain_vision_reader.h>

class BIDSLIB::BrainVisionReader

The BrainVisionReader reads BrainVision file triplets (.vhdr/.vmrk/.eeg) and exposes them through the AbstractFormatReader interface.

BrainVision is the most common format for iEEG (sEEG/ECoG) recordings in BIDS datasets. The format stores data as little-endian binary (INT_16, INT_32, or IEEE_FLOAT_32), either MULTIPLEXED (channels interleaved per time point) or VECTORIZED (channels contiguous).

src/examples/ex_bids/main.cpp
BrainVisionReader brainVision;
const bool bvOpen = brainVision.open(vhdr);
const MatrixXf bvHead = brainVision.readRawSegment(0, 200); // calibrated, volts

Inheritance​

Public Methods​

BrainVisionReader()​

Default constructor.

~BrainVisionReader()​

open(sFilePath)​

Open and parse the file header.

Must be called before reading data.

Parameters:

  • sFilePath : const QString & Absolute path to the primary data file.

Returns:

  • bool — True if the file was opened and parsed successfully.

getInfo()​

Return measurement metadata as FiffInfo.

Returns:

  • FiffInfo — FiffInfo populated from the native format header.

readRawSegment(iStartSampleIdx, iEndSampleIdx)​

Read a segment of raw data.

Parameters:

  • iStartSampleIdx : int First sample index (0-based, inclusive).

  • iEndSampleIdx : int Last sample index (0-based, exclusive).

Returns:

  • Eigen::MatrixXf — Matrix of shape (n_channels x n_samples) with calibrated physical values.

getSampleCount()​

Return total number of samples across the recording.

Returns:

  • long — Number of samples per channel in the whole recording.

getFrequency()​

Return the sampling frequency in Hz.

Returns:

  • float — Sampling frequency in Hz.

getChannelCount()​

Return the number of measurement channels.

Returns:

  • int — Number of measurement channels (rows returned by readRawSegment).

toFiffRawData()​

Convert the entire dataset to a FiffRawData structure.

Returns:

  • FiffRawData — FiffRawData populated with info, calibrations, and sample bounds.

formatName()​

Return a descriptive name for the format (e.g.

"EDF", "BrainVision").

Returns:

  • QString — Human-readable format name.

supportsExtension(sExtension)​

Check whether this reader can handle the given file extension.

Parameters:

  • sExtension : const QString & File extension including dot (e.g. ".edf", ".vhdr").

Returns:

  • bool — True if this reader supports the extension.

getMarkers()​

Return all parsed markers from the .vmrk file.

Returns:

  • QVector< BrainVisionMarker > — Markers in file order; empty if no marker file was parsed.

getChannelInfos()​

Return all channel infos.

Returns:

Static Methods​

unitScale(sUnit)​

isVoltageUnit(sUnit)​

Example​

Used in examples​

ex_bids​

BIDS library: paths, sidecar TSVs, BrainVision/EDF readers and a raw-data round trip.

src/examples/ex_bids/main.cpp, line 119
BrainVisionReader brainVision;
const bool bvOpen = brainVision.open(vhdr);
const MatrixXf bvHead = brainVision.readRawSegment(0, 200); // calibrated, volts
// mne.io.read_raw_brainvision: 32 channels at 1000 Hz, 7900 samples; data[0, 0] = -23.5 uV, data[5, 100] = 38.5 uV
ok &= expect(bvOpen && brainVision.getChannelCount() == 32 && brainVision.getSampleCount() == 7900 && brainVision.getFrequency() == 1000.0f && near(bvHead(0, 0), -2.35e-5, 1e-4) && near(bvHead(5, 100), 3.85e-5, 1e-4),
             QString("BrainVision: %1 x %2 samples, (0,0) = %3 V match mne").arg(brainVision.getChannelCount()).arg(brainVision.getSampleCount()).arg(bvHead(0, 0)));

Authors of this file​