I capture each of the frames and process it pixel by pixel[1]. There are 3 inputs to the simulation

1. The gain knob controls the overall intensity of the effect

2. The selected pins / effects are applied to the frame. I describe a couple of the effects below:

For HClock: If the horizontal clock pin is selected, I cut the frame into variable height slices (some are 2-3px, others 8-20px). For each slice, I calculate a random shift (up to ~20% of the frame width) and move the slice to the left or right by the shift value. Then I randomise between keeping the slice normal (70% of the time), black (15%), or a random color band (15%). I then add a magenta tint + darken every other line to simulate a broken TV signal.

For OD: If output drain pin is selected, I compute a random global offset and per line offet jitter. Then for each of the pixels, I move the red to the left and blue to the right by the jitter value.

After the effects are added, I add a global noise, some corrupt lines (on ~30% of the frames, random horizontal lines of magenta/pink/white, shifted/added)

3. Finally a global hue shift is added based on the second knob.

One thing I realised is that Math.random() produced a lot of noise and flow between the frames looked disorienting. So I used a simple integer hash function to produce a more "deterministic" random number and the frames looked more stable/consistent.

[1] I should probably look for optimisations to prevent the device heating up after a few minutes.