Importing Data from additional sensors

[time4tea]

Following on from #71 - It might be useful to be able to import timeseries data into gopro-overlay so that it can be added to widgets, same as information from a GPX file or GoPro video.

Having had a 2 second think about this - could be terrible idea - it occurred to me that a simple csv file could be used.

We already support access to metrics by name, so accessing arbitrary fields would be relatively straightforward - you'd just have to reference the field in the "metric"

All numeric fields already support time-based interpolation, and these would continue to be interpolated, just as they are now. Interpolation might not be suitable for some fields, but if required we could address that in a different change.

The header row from the CSV file would be used to give fields names, with a required datetime field. Units could be added as per the example.

datetime, field1 (unit), field2 (unit)
2011-12-01T19:03:17.902,1234.5,2325.0
...

I think this might be 1) easy to implement 2) compatible with wide number of sensors

Any thoughts?

[christian-nils]

Thanks for continuing the discussion.

Yes, I believe that the CSV file solution is good!

How would text fields be processed? (e.g., overlaying a ML classifier output on the video)

Another thing, how would you handle unsynced data. For instance one sensor output data at 20 Hz, while the other one at 1Hz.

[time4tea]

Hadn't really thought of any of these things, hence the discussion. :-) I do want to keep things as simple as possible.. right now we don't support text at all within the metrics system, so that might not make the first iteration of such a capability...

There are two approaches that I can think of for multiple sensors...1) repeat the sensor data as required across time 2) allow multiple input files. For 1 the creator of the CSV file would just repeat the value as required for each datetime, so a 1Hz value would be just repeated 20 times alongside a 20Hz value.

This might be more difficult for people to create though.

datetime, 1hz, 20hz
0.00,10,9
0.05,10.2.5
0.10,10,17
...
0.95,10,26
1.00,17,43
....

or just two files.

datetime,1hz
0.00,10
1.00,17

datetime,20hz
0.00,10.9
0.05,2.5
....

[christian-nils]

(Yes, I agree, we should keep it as simple as possible. I was just enumerating the two things I had in mind.)

Regarding the CSV input file, I thought about the second alternative. It seems to be the more elegant way compared with creating duplicated values.