BrainVoyager file formats

With notes on nibabel support.

PR for some BrainVoyager support at


See :

  • All files are little-endian byte order regardless of byte-order on the machine writing the data;

  • BV apparently provides a “BVQXtools” library for reading writing BV files in MATLAB;

BV internal format axes

BV files have a internal format that has axes named X, Y and Z. Quoting from the VMR format definition:

BV X front -> back = Y in Tal space
BV Y top -> bottom = Z in Tal space
BV Z left -> right = X in Tal space

Put another way — the correspondence of BV XYZ to Talairach axes is:

  • BV X -> Anterior to Posterior;

  • BV Y -> Superior to Inferior;

  • BV Z -> Left to Right.


  • BV X -> Talairach -Y;

  • BV Y -> Talairach -Z;

  • BV Z -> Talairach X;


Types of BV files

There appear to be 38 BV file types at the time of writing of which 18 appear to have a page of description on the BV file format index page.

Here are some examples of BV formats:

  • FMR — “FMR project files are simple text files containing the information defining a functional project created from raw MRI data”. This text file contains meta-data about the functional time course data, stored in one or more STC files. See the FMR format definition.

  • STC — “A STC file (STC = “slice time course”) contains the functional data (time series) of a FMR project.” The time-course data of a 4D (“single-slice”) format STC file are stored on disk in fastest-to-slowest-changing order: columns, rows, time, slice. STC files can also contain the data for one single slice (“multi-slice format”), in which case the data are in fast-to-slow order: columns, rows, time. This is a raw data file where the relevant meta-data such as image size come from an associated FMR format file. See STC format definition;

  • VTC — “A VTC file contains the functional data (time series) of one experimental run (one functional scan) in the space of a 3D anatomical data set (VMR), e.g. in Talairach space.”. See VTC format definition; This is a different format to the STC (raw data in native-space) format. The file is a header followed by ints or floats in fastest-to-slowest-changing order of: time; BV X; BV Y; BV Z; where BV X, BV Y, BV Z refer to the BV internal format axes, and therefore Talairach -Y, -Z, X.

  • NR-VMP — “A native resolution volume map (NR-VMP) file contains statistical results in 3D format.”. See NR-VMP format definition

  • AR-VMP — “An anatomical-resolution VMP (volume map) file contains statistical results in 3D format” at anatomical scan resolution. See AR-VMP format definition;

  • VMR — ‘high-resolution anatomical MR’ - see VMR format definition.

  • MSK — mask file. Only documentation appears to be

  • SMP — ‘surface map’. See SMP format definition. Contains one or more “maps”, where a map is a NrOfVertices (number of vertices) length vector of float64 values.