Metadata in LSL

Obtaining data from various hardware devices
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robertg
Posts: 2
Joined: Wed Oct 20, 2021 7:35 am

Metadata in LSL

Post by robertg »

Hello,

We're using LSL for streaming signal data to OpenVibe. It works great but we also need to send some metadata information to OpenVibe (channels settings, names etc.). What's the recommended way to achieve that?

Best,
Robert

Thibaut
Posts: 231
Joined: Wed Oct 31, 2018 9:14 am

Re: Metadata in LSL

Post by Thibaut »

Hi,
LSL can't send metadata, you open a stream for one type of data.
So mix string and float is not possible. If you can communicate in amont, you can set before channel name and other.
The only way I see is to send each time string and cast each time data but the complexity is high for nothing.
Thibaut

robertg
Posts: 2
Joined: Wed Oct 20, 2021 7:35 am

Re: Metadata in LSL

Post by robertg »

Thanks for the reply.
I've managed to read metadata in OpenVibe box but I'm not sure how to pass it further to next boxes.
Do you have any suggestion?

Thibaut
Posts: 231
Joined: Wed Oct 31, 2018 9:14 am

Re: Metadata in LSL

Post by Thibaut »

HI,
it depends on which metadata you want to go from one box to another.
If we assume that it is within OV without any external elements. The matrices already contain the name of the channels, you have the number of channels, the number of samples per channel. the signals also have the sampling information.
If you want to pass the experiment info, you have a stream for that.
If you want to communicate with the outside in LSL.
In your place, if I needed this kind of dynamic information, I would create a special stream which would only send one send at the beginning with the information I want formatted in such a way that the receiver decodes without ambiguity.
But it is not very elegant in my opinion either.
Less dynamically, if I know this information in advance I enter it manually. I only use the network streams if necessary, we try to get as close as possible to real time as possible and the search for streams has a lot of impact on performance.
Thibaut

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