Is 1080p native

4 way test observations:

Test videos: DaVinci’s Demon S02E04, night sword fight by the fire and brawl in the ship’s hold, medium quality for; Star Wars Ep IV remastered, attacking the death star scenes, very high quality file

HDMI and USB-C video input were noticably brighter but compression artifacts were also more visible vs playing locally stored and DLNA steamed versions of the same file. “Multiple sword” effect present in all versions of playback. Stuttering and dropped frames noticeable if you’re looking for it in all versions.

Then I turned auto keystone and auto focus off. Stuttering got maybe 20% better. Not perfect but a little better on scenes with huge fast motion .

My hunch is theres something that needs optimizing in the image processing stack.

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@usafballer it is native 1080p, because for each unique pixel in 1080p source you will see a unique pixel on the screen. the projector chip works on 240hz sending a different pixel every 60hz and pixel shifting to present each pixel on the right spot on the wall. so a square of 4 pixels is created using a single led pixel on the chip.

This is a pico device, that runs on batteries, and the chip inside is one intended for pico projectors. putting in a chip that would have 4 pixels for each 4 pixels shown and would need 4 times the light source, so with current light source you would get almost 4 times less light (i.e. effectively 200 lumen), instead you are getting 800 lumen as the light is concentrated on less physical pixels.

So bigger chip eats about 4 times more power, heats more, and does not go on batteries - it is no longer a pico projector.

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Interesting. Dropping frames on HDMI?

Question, are you feeding in 50/60Hz signals? If yes, what happens with 24, or vice versa?

I think that’s what I’m seeing, yes. It’s very very subtle, but does make for just a hint of jerkiness in frames with big motion. If I watch mouths of speaking actors very carefully I think I can see it there too .

I didn’t check the mode setting on the HDMI from the pi, I’ll try to remember to do that later.

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Thanks! My physics degree is rusty but I get it. Had a hard time finding the specific white paper on it though.

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I’m not sure why you are trying to compare this colourwheel projectors. The PPM is still a single chip DLP projector, the single DLP chip projectors still have to create separate Red, Green and Blue images for each frame. Yet the PPM, with the pixel shift, it has to create separate Red, Green and Blue images for each of the four pixel phases.

Yes, it has advantages in making it lower power and more compact but there are disadvantages too. which are deliberately not being talked about.

Yes, it will display 1080p60, but is it native 1080p? No. In the same way 4K pixel shift projectors will display a 4K image, the manufacturers never actually market them as being “native” 4K. The only manufacturer that I have seen use the term ‘native 4K’ is Sony, but then they really do have LCoS chips with 4096 x 2160 physical pixels. Native resolution is a specific term, and in this instance Philips is using it incorrectly.

In the same paragraph you state that it you see 1920x1080 unique pixels, but then state that a square of 4 pixels is created by a single physical pixel on the chip. Native resolution is a specific term that refers to the physical pixels ONLY. The ‘apparent resolution’, ‘perceived resolution’, or ‘displayed resolution’ is 1080p, but the native (physical pixel) resolution is most certainly not. I am not saying Philips should have advertised it as a ‘native 540p’ projector, but when they called it ‘native 1080p’ they were directly stating it was something it is not.

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There is a minor pivot of the entire DMD, and it creates 4 pixels from one mirror. It can update each pixel of that 4 pixel quad every 1/60th of a second, likely interleaved with an overall 240hz signal. I haven’t seen a good white paper on it, but this is how they can create a 1080P projected image. You keep equating each individual mirror on the DMD with “one pixel” and that’s not true since the entire DMD is in motion, as well as each mirror on the DMD being in an different state. Now, if your eye can detect in a single 1/240th second freeze frame, that only 1/4 of the pixels on the 1080P screen are being illuminated (if I’m understanding this correctly, which I leave room that I don’t), then you obviously need to look elsewhere than this PPM product, but since the entire display fully refreshes in 60hz, and the content you are displaying is going to be 60hz or lower, I’m not sure what you are complaining about here. TI advertizes it as a true 1080P, Full HD DMD, so why shouldn’t Philips get to say that as well?

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I have looked over the datasheets for this DLP (http://www.ti.com/product/DLP230NP) and they don’t use the terms ‘true 1080P’ or ‘Full HD DMD’ so I don’t know where you’re getting that from.
TI also never use the term ‘native 1080p’ (or refer to native resolution at all) with anything to do with the resolution output of this chipset. They state that it “Displays 1920 × 1080 Pixels On the Screen” in their documentation. Philips are the ones who equated ‘native 1080p’ with this device. If TI don’t use the term, why should Philips?

I am an Audio Visual Systems Engineer. I fully understand how pixel shifting works. Apparent resolution from pixel shifting is not native resolution (which specifically refers to the physical pixel array on the chip). I don’t care if Philips want to call it ‘1080p’ or ‘Full HD’, but specifically calling it ‘native 1080p’ is calling it something it is not.

Pixel shifting is good, but there are tradeoffs in image quality and processing that mean a pixel shifted image will never be as good as the image from a native resolution projector.

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The info says: “DMD displays a crisp and high-quality 1080p image” and “Displays 1920 × 1080 Pixels On the Screen” but nowhere does it state that it is “true 1080p” or that it is a “Full HD DMD” (your words), or that it is “native 1080p” (Philips words).

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I think you are being ridiculously obtuse about this

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My only objection is that Philips have specifically used the term “native 1080p” and it is absolutely not a native 1080p DMD. It is a specific technical term, and Philips have misused it.

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@usafballer leave it, I had this discussion already with him, and it is useless :slight_smile:

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@fhteagle do you have a dark room or are you using artificial light (dimmed LEDs)?

If you have artificial light switched on, could you do the tests with the light switched off?

Not sure what ambient light amounts would change resolution or apparent smoothness of motion. What are you looking for exactly?

I recently read a technical paper about artificial light and refresh rates. But I can’t find it anymore.
The key info was, as far as i can remember, if you do have artificial lights like leds and using a projector for home cinema or else, there is a high possibility that this might interfere with your perception.
The simple reason is, that the artificial lights do have a refresh rate on their own, which could make the projected images look unsmooth in motion.

Interesting. But no, I never turn on the LED lighting in the room when the PPMax is really being watched. I have daylight spilling around curtains or night time dark while the PPMax is running only.

@Sefton_Bates You are right. Sefton is not arguing it’s not 1080p. It is. Those are the pixels being displayed as they are manipulated (like an imagery trick) but not actual hardware pixel. This is a way to use less power for a portable device. Am I right or am I right? :sweat_smile: