Okay, so are the defaults in TVout-tweaks for YIQ the correct settings for composite? It just seems so dull. Is this really what composite looks like? Are these the lowest values possible with composite, before filtering restores any of the lost resolution?
I think my first TV must have had at least a two line analog filter because these colors seem way worse than I remember.
Maybe try to remove any color transforms and leave only the signal-bandwidth emulation portion. I don’t think there’s an end-it-all shader for ntsc, but picking bits of code here and there it’s possible to make something closer.
Also trying a system more deterministic with its palette, the NES has many possible palettes, I don’t have vivid memories but in any case what I had was the “Creation”.
From what I could read about composite, the specification allowed for more resolution up to 3.579 Mhz, but this was for “full-power analog transmission” and I believe for 625 lines. In reality at the time only 1.3 Mhz was used for I, and later on I and Q were equalized to 1 Mhz, which makes it compliant to the 4:1:1 chroma subsampling for NTSC.
I don’t know if analog filters had any kind of convolution filter for sharpening or so. My initial attempt would be to scale up chroma with lanczos or similar to full chroma before RGB conversion.
Hey just curious why you deleted your comment, seems perfectly relevant to the discussion. The whole reason I started this discussion is because I never remember dithering being blended on any of the TVs I’ve used and I’m wondering how far back in time you need to go to actually blend dithering. Like… early 1970s maybe? lol. Kinda puts a damper on the whole “artist’s intentions” argument.
Your technical knowledge is way ahead of mine here so bear with me.
So if it’s 4:1:1 and 525 lines, would that be
Y: 350
I: 87.5
Q: 87.5
Those seem like more reasonable values to me. These would be the maximum values, or what you’d get with a good comb filter that restored all the lost information (right?).
Current defaults for TVout seem like they’re based on the standards for 1950s TV broadcasts. I’m guessing that these standards were based on the crappy TVs of the time and so they expected a certain amount of lost resolution.
Is that because of the 4:1:1 thing?
If you get some time, I’d really like to see some photos.
I’m curious what the scanlines look like with composite video sans filtering. Some comparison shots showing the same screen via RGB would be useful, I think.
Good stuff. The black gaps are almost as prominent via component as via RGB; only slightly fainter in certain places via composite. I’m guessing the lack of scanlines over the white text in the first shot is due to camera focus; they’re quite visible in the upper left of the last shot. Most of the difference is in horizontal sharpness, color and rainbow artifacts (and I’m guessing dot crawl). Another interesting observation is that the colors are nowhere near as dull in this shot compared with what you get with most NTSC shaders. If anything, certain colors seem oversaturated compared with RGB. Any idea as to why this might be the case…?
Could be the palette on the RGB connection. It’s a MiSTer, but all RGB NESes share the same limitation of using an emulated PPU. I don’t recall which palette I’m using, but there’s a good chance it’s one of FBX’s composite captures.
I think it’s very interesting how blue the dots over the fence are in the composite shot vs dark gray in the RGB shot. And yeah, the solid white on the title screen shot is a camera/exposure thing.
I found it difficult to get the beam width variation right with any of the standalone scanline shaders so I wound up using an overlay for scanlines, lol. (5x-scanlines6-1920x1080 @ 100% opacity). I think this looks kinda close at normal viewing distance, still not as dynamic as the PVM though.
This is tvout+ntsc-256px-composite+interlacing minus interlacing. I only enabled TVout color levels and set gamma input to 2.4. Color palette is “composite direct FBx” in Nestopia.
Colors still look closer to those in the RGB photo, though… color is hard. 
It’s okay, but I’m not really blown away or anything… beam variation, brightness and color still leaves something to be desired. It’s tough getting the beam variation right without making the image too dark. I think I’ll have to try cobbling together a custom shader using bits of code from guest-dr-venom.
Just read this line here, and thought it could be related to the rainbowing of the BW areas.
It is important to note that while the NES only generates eight (8) samples of NTSC signal per pixel, the wavelength for chroma is 12 samples long. This means that the colors of adjacent pixels get mandatorily mixed up to some degree. For the same reason, narrow black&white details can be interpreted as colors.
By the way, just a little bit lower they justify the use of the “FCC-sanctioned YIQ-to-RGB conversion matrix”
@Nesguy Found this on comb filters, no formulas but good explanations, in case you haven’t read it already.
Related, found this 2 page RGB-Composite comparison about the output of various consoles interesting - check out the Neo Geo at the bottom - composite looks terrible! Not entirely surprising because of the arcade origins, but there’s no S-Video on the homesystem either.
I got a new CRT - a 14" inch one which was supposed to be barely used. Compared to my old 20 inch one it looks a good deal sharper, and portability and rotation is a big plus. Testing the inputs, I got back to the Wii to check the composite. I was astonished again how good it looks , but this prompted me to think if I could maybe degrade the signal to make it closer to original systems without using any emulator filters. I had an unused DVD-Recorder around, so I plugged the Wii into the CAM AV input there and used the Recorder’s own composite output to plug into the TV. That made the picture significantly worse, way more blurrier. There still not much going on in terms of dot crawl or other things you’d associate with old composite outputs, but might be an interesting thing to try if you only have the modern stuff around.
I took some photos, but currently I also have to experiment with some camera apps on a custom rom’ed phone, still they might give a hunch of how it looks. First pic is always Wii directly connected, second via recorder.
Nice photos!
What’s the model number? I wonder what kind of comb filter it has.
“Curiously” youtube showed me this video after reading this post, it’s interesting.
This is an AEG CTV 4800 VT. Likely some cheap thing made at the end of the CRT lifecycle. But as I wrote, the selling point here was that the tube hasn’t seen much action. I was originally talking to someone for possibly getting a nice blue Orion, but that model was considerably older, and the guy couldn’t tell me if the SCART input accepted RGB, so that was a no-go. I’ll probably get another 14 inch one for aesthetics and comparison, and maybe a larger Trinitron if I find one in the 16"-19" range.
That composite is only useful on some 8bit like Atari 2600 and Zx spectrum to hide the jaggies. Everything else looks way better on RGB. I have a Wii and a PC to Trinitron and I can tell you that for sure. 
Some Megadrive games too with heavy dithering. Sometimes though I enable an ntsc shader on that systems to filter the image a bit to look authentic on CRT.
A lot of SNES games relied on composite video tricks as well. Basically anything from the composite video era should use composite video because the graphics were likely designed with that output in mind.
I use GDV and use a custom NTSC mode to minimize undesirable artifacts while still blending stuff that should be blended.
Took some photos recently for social media, might be interesting for some here as well: Wii composite can be very sharp. Still, notable difference with RGB. Third pic is with Blargg’s composite filter activated.
Now, I did get another, older CRT from around 1995, and the composite is notably worse (more color bleeding etc.), but it’s not entirely clear to me to what extent this is due to it’s condition, when I received it, the composite looked so bad I thought it was unusable. After some adjustments I managed to make it look ok, at least for my purposes - it’s an analog chassis (useless service mode), probably won’t mess around too much with the pots, at least for the near future.
Indeed, the comb filters used to re-separate the individual luma and chroma from the composite signal got significantly better (and the best of them got significantly cheaper, making them available in more models) toward the end of the CRT era.
Lovely shots, what TV is it?
Nintendo makes solid AF cables as well which helps. (Cable quality matters, my wallet cries because of it 
You can get component cables for your Wii and your wallet can cry too )
