OverflowError when HD-EEG data streamed to SigVisualizer

[iPsych]

LSL SigVisualizer repeatedly crashes when It receive streamed EEG Inlet from 256ch EGI Amplifier. The program starts properly and visualize very short part of initial eeg signals from 256chs, than crash.

Traceback (most recent call last):

  File "/Users/User/Downloads/App-SigVisualizer-64fe663e88246c14fbd60b14eff84c228f5a85a6/paintwidget.py", line 216, in paintEvent

    -self.dataBuffer[0][ch_idx] + chan_offset)

OverflowError: argument 4 overflowed: value must be in the range -2147483648 to 2147483647

Abort trap: 6

[Yida-Lin]

Hi @iPsych , I currently do not have a physical amplifier here so I could not reproduce this issue. Do you have an XDF file recording that came from that amp, that I can use to simulate on my end?

[mvidaldp]

I had the same problem. After debugging for a while I realized it lies on a downsampling error:

A quick fix is to change this line:

App-SigVisualizer/paintwidget.py

Line 58 in aa754e6

stream_params['downSampling'] = srate > 1000

Setting downSampling to False up to 1024 instead of 1000 Hz, since it's a common sampling rate in EEG recordings. Thus if your stream sampling rate is below 1000 it will work without this hack.

@Yida-Lin, @iPsych, please could you fix this?

I'm quite sure it's the same error referenced on the other OverFlow issue:
#18

[Yida-Lin]

Hi @mvidaldp thank you for your suggestion; sounds good, I created a PR #21 and could you please help verify whether it solves the problem? Thanks!