How do i control when to write data to an.ov file

About BCI and box tutorial/demo scenarios bundled with OpenViBE.
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Avril
Posts: 1
Joined: Wed Dec 15, 2021 4:59 am

How do i control when to write data to an.ov file

Post by Avril »

Hi, I have an OpenBCI device now and I use it to connect to OpneVIBE, but I don't know how to mark my data.
When I use the motion imagination routine, the script will randomly give directions, and I need this feature.
When 20 sets of data have been sampled, the motor-imagery-bci-graz-stimulator script sends a stimulus

Code: Select all

box:send_stimulation(1, OVTK_StimulationId_ExperimentStop, t, 0)
, and then the program ends.
I was wondering if I could use a similar way of sending a stimulus to indicate that the data would not be written to an.ov file if the picture was not displayed.
Because I only do motion imagery when the indicator picture comes up, the data before that is useless.
I need to segment the whole process, so if I can write the.ov file when the image comes up, then it's really easy for me to analyze, otherwise I don't know what to do with that long data, honestly.
My English may not be very good and some questions may not be clear,sorry.

Thibaut
Posts: 264
Joined: Wed Oct 31, 2018 9:14 am

Re: How do i control when to write data to an.ov file

Post by Thibaut »

Hi,
I'm not sure I really understand so I might be on the wrong track.
For offline analysis of your signals OpenViBE is not the best tool, people use Matlab and EEGLab and other Python. In both cases it is with gdf or csv files, the ov format being exclusive to OpenViBE (you can convert your files there are several example scenarios for that where you just put a reader and a writer following).
On all your huge file, if you have recorded the stimuli in the file you have the start and end times and your analysis script just needs to locate the lines it should take (from such stimulation to such other stimulation).
It's possible to preselect on Openvbie but it's a ugly hack, it's better to keep your file, load and select what you wan't in your analysis process.
Thibaut

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