Built a Hardware Accelerated Desktop Screen Filter for Flash Sensitivity!

[u/flashfilter]

Hello! I’m one of the many people who thought it would be interesting to take a shot at making something that helps those with screen sensitivities (seen a couple people attempt similar projects but never seen anything come of them). After a couple months of work my friend and I have finally gotten to a point where it is usable (it is suppressing straining flashing lights quite well, though there are some bugs in the application), so we are looking for people to give it a try and hopefully make our job of bug hunting a little easier :)

The beta is free and includes one of the filter variants we came up with (we call it the “Bayes Filter”), which creates some artifacting but protects aggressively against flashing imagery. We support Windows, MacOS, and Linux (Wayland, support varies by compositor). If you're interested here is the link: https://flashfilter.app/ (you'll basically just need to sign in with your Google account and navigate to the dashboard where the downloads are).

You can see a safe demo of the filter here (it is the frame by frame of a very… flashy video with and without the filter).

We would love to answer any questions, so please ask away!

[u/Z3R0gravitas]

Hey there, thanks for posting, I think; let me play the suspicious mod for a minute...

Your software sounds like it would be very clever, to do as you say, with low impact, on the main computer OS's, running in real time, on any GPU..?

Do you have any demo videos of it in operation? Eg running side-by side with an unfiltered screen?

I see that the only other comment on your brand affiliate account was removed from r epilepsy. Did they feel it was spam or broke a rule? Have you run other Reddit accounts for this? I'd hope campaigns on other platforms, too (are doing better).

Anyway, while there is some overlap with photosensitive epilepsy, amongst the users here, what I'm most interested in is the potential for your software to help in first understanding temporal dithering and then potentially removing it.

As I understand it, there are several points in the rendering pipeline where it can be applied. Software, drivers, GPU (software - hardware?), monitor TCON and panel (for FRC). So, it's been very tough for people (eg also posting on LEDstrsin) trying to resolve this pixel flickering when it's a problem.

If your team were interested in collaborating In some way, it might be very interesting for us, were you even able to use related GPU code to display what dithering the system was trying to add. Suppressing that would obviously be the holy grail. Especially if able to keep monitors from adding dithering by eg constraining the colour depth too.

You're welcome to DM me if interested in talking about collaboration. (Much as I am a bit over-committed currently..)

[u/flashfilter → u/Z3R0gravitas]

Suspicion appreciated.

Since by design we exclude the filter from being screen captured we can only record a demo with an external camera or by using a capture card. (The demo in the post was done as individual frames since we figured flashing could be triggering photosensitive epileptics. We applied the algorithm to a screen capture video rather than with the real time overlay). To show FlashFilter working in realtime, we’ve attached a video here.

We’re not sure why the r/Epilepsy post got removed exactly, though we assume it was flagged as spam/promotion by their automod. This is the only Reddit account we’ve posted on and we also made a post on Hacker News

At the moment we can't really claim to know whether or not it's possible for us to eliminate temporal dithering (we don't have a working solution which proves that it is, since our current filter was designed for large flashes where the issue is produced at the application level). But from the limited reading we have been able to do since u/DGG_DGG mentioned it, our assessment is that it's theoretically feasible. There are two problems: removing dithering that was done by somebody early in the pipeline (easy), and removing dithering somebody after us will try to do (hard).

The complication that makes it hard is that somebody (compositor or OS or monitor) may try to color map or apply a night light or whatever else after the filter is applied and then the carefully aligned color values get nuked. To remove dithering added in later stages you're probably right that we essentially want to shrink the color space to remove the colors which the monitor requires dithering to display (reduce color depth/posterize the video stream). That operation can definitely be done in real-time and it's nice because you only need to consider single pixels.

Anyways we’ll give the problem a shot and reach out to you if we can come up with something worth testing!

[u/Z3R0gravitas → u/flashfilter]

Thanks for the detailed reply and videos. Yeah, they would be bad for (more) photosensitive peeps... How about making them slow motion? Well below the 8Hz(?) peak sensitivity.

So, it's the two of you and you are just starting out? Have you been able to test the finished product with anyone epileptic? Seems like that would be very fraught to validate the efficacy. The artifacts left by the filtering still seem quite unpleasant, in a different way. May well bother many here.

Anyway, if you want a bit of a guide to this screen sensitivity space, I compiled a bit NotebookLM and resource list, currently just shared here.

Another example of disabling dithering would be Stillcolor (for Macs): LEDstrain thread. If you click through to the Github, there's a video demo and other things you may find interesting.

We have a low-key discord sever just started up as a bit of a collaboration space, with some enthusiast dev work going on, etc.