Data format

[yvessl]

Hi,

Could someone tell me which protocol the acquisition server is using to send data? Are they encoded in the EBML format?

Regards,

Yves.

[yrenard]

Dear yvessi,

the acquisition stream is indeed encapsulated in an EBML structure. Browsing the developer documentation, you will find a description for each stream type. If you are not familiar with EBML, I suggest you first read the following doc pages :

• What is EBML ?
• Formating EBML streams
• Parsing EBML streams.

If you want some reference implementation, you should look at the openvibe-plugins/stream-codecs folder.

I hope this helps. Can you tell us what particular situation leads you to decode the stream by yourself ?
Yann

[yvessl]

I hope this helps. Can you tell us what particular situation leads you to decode the stream by yourself ?
Yann

Hi Yann,

thank you for your quick answer!

I'm interested in understanding the full process of developing a BCI platform for my studies.

And also "comparing" your design to that of: http://openeeg.sourceforge.net/neuroserver_doku/

So is that the "DTD" used for acquisition?

• OVTK_NodeId_Header
• OVTK_NodeId_Acquisition_Header_ExperimentInformation
• ... some experiment information stream header
• OVTK_NodeId_Acquisition_Header_Signal
• ... some signal stream header
• OVTK_NodeId_Acquisition_Header_Stimulation
• ... some stimulation stream header
• OVTK_NodeId_Acquisition_Header_ChannelLocalisation
• ... some channel localisation stream header
• OVTK_NodeId_Buffer
• OVTK_NodeId_Acquisition_Buffer_ExperimentInformation
• ... some experiment information stream buffer
• OVTK_NodeId_Acquisition_Buffer_Signal
• ... some signal stream buffer
• OVTK_NodeId_Acquisition_Buffer_Stimulation
• ... some stimulation stream buffer
• OVTK_NodeId_Acquisition_Buffer_ChannelLocalisation
• ... some channel localisation stream buffer
• OVTK_NodeId_Buffer
• OVTK_NodeId_Buffer

Thanks,

Yves

[yrenard]

Yes that's it. You will then have to check the {experiment information|signal|stimulations|channel localisation} streams description to decode sub streams.

Yann