Fake Polymega Composite Filter Pictures?

Edit: March 27th 20019 Polymega have provided some more screenshots of this effect. While I am not 100% convinced either way anymore of which is a picture from a CRT and which isn’t, I am not revising history (Git has taught me that this is wrong) because the article below did reflect my opinion at the time and that will remain here forever whether it is right or wrong. For the record I have not changed my opinion. Moreover the article ALWAYS stated that this could in fact be a “very good software filter” so everyone needs to calm down.

Here is a comparison between Polymega’s latest screenshot compared to the original. I feel these are different filters, if not different screen technologies altogether… you be the judge:

Original Article Starts Here

I recently stumbled upon these two posts from Polymega’s Twitter feed boasting 2 filter modes for the Polymega: a “Composite Filter” and an “RGB Filter”. The composite filter caught my eye immediately. I theorize that the picture of the Composite filter they posted is fake and is in fact an actual picture of CRT. I must admist it’s entirely possible that the Raspber.. eh Polymega outputs to a CRT – or that this is in fact a very good software filter which somehow gives the perfect illusion of an offset shadow mask. Either way, the following article illustrates my reasoning.

Twitter Posts

Composite Filter

RGB Filter

Screenshots include here in case they delete these posts in the future.

RGB Filter Composite Filter

The Problem

The problem has to do with how a CRT is constructed as opposed to how an LCD is constructed.

LCD Pixels

Pixels on an LCD are presented in a square grid. Each adjacent pixel is directly next to each other pixel as shown below:

CRT “Pixels”

A CRT doesn’t have pixels per se, but the grid of colour elements on consumer CRTs is presented in an offset grid. Each adjacent pixel is offset to each other pixel as shown below:

And here is a lovely side by side of different technologies of “pixel” grids for consumer displays.

Polymega Filters

Let’s now look at a closeup of the supposed Polymega filters side by side. FYI polymega is a small computer, outputting HDMI to a modern display. On the left is the supposed “CRT Composite” which clearly shows a CRT geometry and in my opinion is not a photo of a CRT filter on an LCD display. It appears to be a closeup picture of a CRT playing Sonic The Hedgehog.

On the right is their “RGB Filter”. This image clearly is a closeup of an LCD.

Why would Polymega try to pass off a picture clearly taken on a CRT as a “Composite Filter” for their computer? Why would two different displays altogether be used to demonstrate filters which presumably are a simple menu click away? Am I wrong? Can modern technology fool me into thinking this is in fact a CRT when it isn’t?


Electronics engineer and retrogaming fanatic!

9 thoughts on “Fake Polymega Composite Filter Pictures?

  • 2019-03-26 at 18:38

    Filters can’t be measured! 😀

  • 2019-03-26 at 20:31

    Look, I’m sure they have countless customers who never had a problem and therefore it can’t be a problem, ever, and can never harm your CRT.

    Obviously you have a vested interest in selling accessories for original consoles and therefore find fault with the *immeasurable* quality produced by such phenomenal devices.

    Obviously the only reason you release your hardware designs as open source is because they’re worse than everyone else’s and you’re just biding your time to produce your own FPGA flash cart PC Engine with analog output board with 32X support.

  • 2019-03-26 at 23:40

    Polymega has posted several videos, direct capture and offscreen camera recording, and the filters on display are exactly the same as their posted screenshots. Whether or not they deliver on their final product and it turns out well, I think you owe them an apology and should retract this post.

    • 2019-03-27 at 00:00

      This article was my expressed opinion at a point in time and will stay here forever, whether it does me good or bad. I will not be a revisionist. I have discussed this topic in a rather civil manner with Polymega on Twitter, if these shots do in fact come from some software filter and managed to fool a bunch of people then that’s amazing publicity for them.

      • 2019-03-27 at 10:09

        By retraction, I meant admitting fault and adding a correction/update. I wasn’t suggesting you delete your post. Also that tweet you posted in the update is doing a bad comparison, no thanks to Polymega posting that one dark video. In the others you can see a much cleaner and brighter video where the CRT filter and the LCD subpixel layout matches the initial Polymega “bullshot.”

        I’m perplexed there is any controversy or suspicion at all. Anyone who has kept up with the emulation scene knows that more advanced and impressive shaders have existed for years. There’s nothing special or unbelievable about these two Polymega filters. People are only getting thrown off because of the LCD they’re using.

  • 2019-03-27 at 03:12

    Honestly, those CRT filters screenshot do not look impressive to me and the later certainly do not look like my Megadrive with SCART RGB on my old Trinitron TV (it’s much darker and looks more like a CRT monitor).

    They just look like some of those CRT shaders provided with Retroarch (some of them are already able to simulate different shadow mask or aperture grill and even phosphor glowing wth very high resolutions, see https://forums.libretro.com/t/please-show-off-what-crt-shaders-can-do/19193/45) they probably just reused that, I doubt they took the risk to fake something that is a very common emulation feature nowadays.

  • 2019-03-27 at 05:43

    I think the basic flaw of your argumentation is, that the modern display it is viewed at, has a much higher resolution. When you simply count the pixels in the screenshots, you can tell, that there must be scaling involved.

    When you look at these closeups you are still not seeing the actual pixels of the LCD Display, every pixel here is probably 16 oder 25 LCD pixels (or more if it is a 4k Display) and so it can fake the offset pixel look, by simply showing black on some of them.

    Sorry – but I don’t get your argumentation at all this time.

    • 2019-03-27 at 10:31

      I agree with this and wondered as much. Initially I thought Polymega was using a pentile display or some other screen with a non-square grid, but now it seems clear that we’re not actually seeing the fine subpixel layout of the LCD they’re using. If they used a decent camera with a macro lens we would actually be able to see that the handful of white “pixels” that make up the width of Sonic’s eye are actually numerous smaller real pixels.

  • 2019-03-27 at 08:10

    Either its a differet display or a the whole thing is shown at zoom on the display(its already blown up, kinda like it is here) which would be fine if you had an _8k_ monitor I guess. on normal fhd you would see just like 1/8th of the picture though zoomed like that to show that effect so there wouldnt’t be any actual point to that.

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