Help
Ventris shows the signals and frequency bands of an EEG recording, right in your browser.
Your recordings stay with you
Everything runs in your browser, so your recordings never leave your computer. Nothing is uploaded.
Open a recording
Select Open a recording and choose an EDF or EDF+ file, or drop a file anywhere on the page.
The whole file is read into your browser's memory, so a very large recording may not open.
The demo
Ventris opens on a demo. It's generated data for trying out Ventris, not a real recording.
A blink shows in Fp1 and Fp2, and alpha builds at the back of the head when the eyes close at 0:20.
Read the traces
Each row is one channel. The ± figure under a channel's name is how far that row reaches either side of its middle.
Each row has its own ± range, so compare shapes rather than heights.
Point at a trace to read the recorded value at that moment.
Move through a recording
| Window | Sets how much of the recording is on screen. |
|---|---|
| Trace size | Makes every trace smaller or larger. The ± figures change to match. |
| Slider | Moves through the recording. |
| Swipe | A sideways swipe on the traces moves through time. So does holding Shift while you scroll. |
Keyboard
Select the traces or the slider first.
| Page Up Page Down | Move one window later or earlier. |
|---|---|
| Home End | Go to the start or the end. |
| Arrow keys on the traces | Move the cursor to read values: left and right through time, up and down between channels. |
| Arrow keys on the slider | Move a tenth of a window. |
Frequency bands
Each bar is one band's share of the 1 to 30 Hz power in the window on screen, from Welch spectra averaged across the EEG channels. The bars update as you move.
The line under the bars gives that range and how many channels were averaged. Point at a row for a more exact figure.
Only EEG channels sampled at 64 Hz or faster are measured. If bands can't be measured, the line says why.
Annotations
Annotations in an EDF+ file appear on the time axis. Select one in the list to jump to it.
Time domain
These figures cover the whole recording, pooled across the EEG channels. The line under them says how many. EEG channels in a different unit from the first one are left out.
| Overall SD | The standard deviation of all those samples together. |
|---|---|
| Lowest SD, Highest SD | The channels with the smallest and largest standard deviation, leaving out flat ones. |
| Flat channels | How many channels hold one value throughout. |
Info
These details come from the file's header. They follow MNE-Python's EDF reader, so they usually match mne.io.read_raw_edf.
EOG, EMG and ECG channels are read from their labels and stay out of the EEG measures.
Light and dark
Ventris follows your system's theme until you pick one with the switch next to Help. Your choice stays in this browser.
Limits
- Ventris is a research tool, not a medical device.
- BDF files aren't supported yet.
- It doesn't filter, re-reference or export signals.
Source code
Ventris is free and open source. Read the code on GitHub, or report a problem.