Converting .ov files to Matlab

  • NB: Document last updated for OpenViBE 2.0.1 (28.Mar.2018).

Briefly: Matlab can be used to do offline analysis of signal files recorded with OpenViBE. Usually the recorded data is in the .ov format, which Matlab does not read. Here are some convenience scripts that can be used with OpenViBE 1.1.0 or newer to automatically convert the .ov files to Matlab’s .mat files, without the user having to manually  save to formats like CSV or GDF and importing them to Matlab.

Requirements: Compiled and installed OpenViBE 1.1.0 (or newer) and Matlab.

Limitations: Due to the script using CSV as an intermediate format, the full numeric precision of the original .ov binary is not kept. The conversion to CSV uses 10 decimal points precision.

Downloads: ov2mat-v0.1.zip archive.

Troubleshooting:

  • The scripts were designed for OpenViBE 1.x. On Windows, in openvibe 2.x series, the application is installed into paths like “C:\Program Files (x86)\openvibe-2.0.1″ to allow multiple installations of OpenViBE at the same time. You need to modify the .m scripts in the archive to point to the correct path.
  • On Linux, you may need to modify the scripts to specify path where the Designer launcher script can be found (usually under dist/)
  • In Matlab 2017a, it seems that readtable() function has difficulty parsing the .csv header and as a result, complains about PATTERN. You can sidestep this problem (and lose the channel names) by giving that command an additional parameter pair  ‘HeaderLines’,1 in convert_ov2mat.m file.

Happy hacking!

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