Please explain timestamps for /muse/eeg


#1

When I use Excel to view a test.muse file converted to test.CSV by Muse-player, I see a timestamp in the first column (e.g., 1420950088.538). The same timestamp value is repeated for multiple lines (typically 10-16) of 4 EEG values. What’s going on here? What is the correct time value to use for a given line of EEG values?

[When I use the --osc-timestamp option to start MuseIO, I get two additional values after the EEG numbers (e.g., 1420950088, 431547) but they too repeat for several rows.]


#2

The timestamps in the CSV files from MusePlayer are the time-of-arrival of the Bluetooth packet containing that information. The packets contain multiple messages, so often more than one message will have the same timestamp. The Bluetooth module buffers data when the connection is temporarily dropped, also, so packets can sometimes be delayed and then arrive suddenly in bunches.

Take a look at this thread for some more detail: http://forum.choosemuse.com/forum/developer-forum/3892-how-to-handle-varying-timestamp-deltas


#3

Thanks, that helps. Since I don’t seem to be getting any dropped samples, I guess I’ll just assume that each successive /muse/eeg row corresponds to a time delta of 0.0045 seconds.