N64: RGB vs S-video colours

[andykara2003]

Hi guys - I have a question that I don't think has been satisfactorily answered before.

When comparing an NTSC N64's RGB output (either THS7314 or THS7374 amp) to the S-video output, the S-video colours are cleaner more vibrant. The whites are whiter and the colours are more lush. The RGB colours look a little more muted.

It's not dependent on the TV or the N64 model (I have some experience with N64s & have lots of great CRTs, both consumer & pro - and lots of N64s with RGB mods in various revisions (some pre revision 4 and some post). I first noticed this a few years ago but I'd really like to get the bottom of this.


I wouldn't want to switch to S-video from RGB - obviously the image is significantly inferior when using S-video and would bother me - I just with I could have the RGB image with the lush, vibrant colours of S-video..

Can anyone shed any light on this?

[FBX]

It's probably due to the difference in the on-board encoder chip versus the straight RGB signal that gets fed into the THS chip. Either that or S-Video signals are processed differently on the display end. I know that when it came to the NES on my PVM, the colors were so vibrant on composite as to be out of range of RGB on a few of the color entries.

[Ikaruga11]

Another thing to note is later revisions of the Nintendo 64 have sharper Composite and S-Video output, while also having even brighter, more lush colors.

[andykara2003]

It's probably due to the difference in the on-board encoder chip

That was my initial hunch. I don't think anything can be done to apply that colour encoding to RGB in that case

Another thing to note is later revisions of the Nintendo 64 have sharper Composite and S-Video output, while also having even brighter, more lush colors.

I was aware that the revision 8's (inc most funtastics) have a sharper composite & possibly S-video but I can't live with either in place of RGB. No worries, I have a feeling that there's no solution here. Just notching up the contrast a little helps and it doesn't put me off that much.

[Ikaruga11]

That was my initial hunch. I don't think anything can be done to apply that colour encoding to RGB in that case

Maybe color mastering during an N64 game's development was done with the encoder chip in mind.

I was aware that the revision 8's (inc most funtastics) have a sharper composite & possibly S-video but I can't live with either in place of RGB. No worries, I have a feeling that there's no solution here. Just notching up the contrast a little helps and it doesn't put me off that much.

Yeah. I have an NUS-CPU-08 Revision N64 (Charcoal Grey model!) with the official Nintendo S-Video Cables, and the difference in color between that and an NUS-CPU-03 Revision launch day N64 is night and day.

So are you only talking about the official RGB mod for NUS-CPU-04 Revisions and earlier? Or do these muted colors also appear on the universal N64 RGB boards like Tim's as well?

[Blair]

later models of N64 have better s-video? thats interesting since i'm using a launch N64 with a hori cable and the s-video output quality while still better then composite is incredibly soft and almost too blurry to enjoy (even on a PVM). i've been debating RGB modding my n64 unit but i'm not sure if it's worth the expensive investment. as the N64 was not one of my favorite systems growing up. (but i'm very curious what a good RGB mod could look like with the OSSC on my setup).

[juji82]

This is what an ultrahdmi kit can do. I think a good rgb mod along with OSSC or XRGB mini won't be that much different. Set it at 1080p


https://www.youtube.com/watch?v=ba5TlNYGAZE

[Blair]

that looks very nice, but I can't solder worth beans. so I would need to find a modding service.

[andykara2003]

Maybe color mastering during an N64 game's development was done with the encoder chip in mind.

This might be the case.

So are you only talking about the official RGB mod for NUS-CPU-04 Revisions and earlier? Or do these muted colors also appear on the universal N64 RGB boards like Tim's as well?

They appear on all RGB mods as they all look basically the same across all revisions.

Yeah. I have an NUS-CPU-08 Revision N64 (Charcoal Grey model!) with the official Nintendo S-Video Cables, and the difference in color between that and an NUS-CPU-03 Revision launch day N64 is night and day.

I don't actually have a revision 8. Have you compared the s-video of the revision 8 to an RGB mod (of any revision) and noted the *purity* of the image, rather than the colour difference on a decent CRT? I think that there will still be a significant difference in the purity of the image (i.e. absolutely zero artefacts/smearing), which is more important than colour to me.

A very knowledgable N64 guy (Link83) had this to say about the revision 8 sharpness: "To me it looks like the equivalent of turning up the sharpness control on your TV, which adds image data which shouldn't really be there."

Even small amounts of artefacting like this totally puts me off and I guess that compared to a pure RGB signal it's inevitable.

This is what an ultrahdmi kit can do. I think a good rgb mod along with OSSC or XRGB mini won't be that much different. Set it at 1080p

I have this and it's a fantastic bit of kit - but not quite as good as an RGB mod on a decent CRT to me. It's much more versatile than the OSSC/XRGB mini route though. It sits mostly unused under my non-gaming living room TV.

[Einzelherz]

Have you put two nearly identically calibrated monitors side by side to test this theory? E.g. 1 calibrated svhs and one rgb to the same color, luminance and then compared?

[andykara2003]

Have you put two nearly identically calibrated monitors side by side to test this theory? E.g. 1 calibrated svhs and one rgb to the same color, luminance and then compared?

No, I doubt many people have, but surely RGB is a purer/better signal than S-video? Hence the almost universal push towards RGB in the retro gaming scenes like this one. Although perhaps the fact that the N64 has a relatively poor output in the first place negates this somewhat and the revision 8's S-video is closer in quality to RGB than in other consoles. I know the lower revision N64's S-video looks pretty rough.

As an aside, I've found that high end monitors like my BVM actually can paradoxically mask the deficiencies/qualities of the N64's image due to the thick scanlines (which I feel don't suit the N64's image at all), so I prefer to compare on a decent low-hour consumer CRT.



[EDIT: Damnit I'm going to buy an NTSC revision 8 to test this out. Perhaps the rev.8's are close enough to RGB to not be an issue.]


[EDIT 2: Just bought a revision 8 clear smoke grey (mint!) US N64, Serial number NS289133758 (so revision NUS-CPU-08-1). I have a couple of official S-video cables so looking forward to seeing the difference in colours and clarity. I'll get back here with my findings when it arrives.]

[Einzelherz]

I'm interested in the difference between revisions, but I meant that the TV/display itself might be the reason that a seemingly lesser video signal looks better.

[andykara2003]

Ahh I see - so I tested this thoroughly with the Sony and my Loewe E3001 chassis and I can say with 100% certainty that the s-video output has cleaner colours and purer whites than the RGB output. Looking at the 3 spiritual stones in Ocarina of time (good example, having 3 primary colours), the difference is really clear.

Conversley, to describe the deficiencies of the s-video image (non rev. 8) compared to the RGB image, I would say that it looks like a combination of a slightly oversharpened but also 'smeared' image and slightly oversaturated colours. However, as I say the colours look noticeably cleaner than RGB.


As to the people who say that the revision 8's are sharper, I wonder what they mean. Hopefully they don't mean that the slightly 'oversharpened' quality to the s-video is merely accentuated but that it's actually that the encoding is of a higher quality. Time will tell.

Would you mind chipping in GeneraLight as you have the revision 8? Is the S-video output really a *better* image compared to that of a lower revision N64? Not in terms of colours but of reduced artefacts usually associated with s-video?

[Ikaruga11]

Ahh I see - so I tested this thoroughly with the Sony and my Loewe E3001 chassis and I can say with 100% certainty that the s-video output has cleaner colours and purer whites than the RGB output. Looking at the 3 spiritual stones in Ocarina of time (good example, having 3 primary colours), the difference is really clear.

Conversley, to describe the deficiencies of the s-video image (non rev. compared to the RGB image, I would say that it looks like a combination of a slightly oversharpened but also 'smeared' image and slightly oversaturated colours. However, as I say the colours look noticeably cleaner than RGB.


As to the people who say that the revision 8's are sharper, I wonder what they mean. Hopefully they don't mean that the slightly 'oversharpened' quality to the s-video is merely accentuated but that it's actually that the encoding is of a higher quality. Time will tell.

Would you mind chipping in GeneraLight as you have the revision 8? Is the S-video output really a *better* image compared to that of a lower revision N64? Not in terms of colours but of reduced artefacts usually associated with s-video?

'Better' in this case is subjective, I'd say. Some people might prefer the blur and darker colors of the earlier revisions. As Link83 said, the Revision 08 models look like a sharpening filter is used. Or the MAV-NUS is simply a higher quality video encoder chip than the VDC-NUS, as individual pixels are more discernible. Graphics are noticeably crisper. You can see the pixels and dithering on some graphics, which looks amazing most of the time but can be a bit distracting in a few instances. I'm not sure if it's my cables or CRT. Colors are also more colorful and vibrant as well. I'm not sure if the colors are related to the sharper image, or are something different altogether. They're extremely nice though.

I feel like the Revision 08 makes any artifacts more visible.

[andykara2003]

As Link83 said, the Revision 08 models look like a sharpening filter is used.

Hmm that's what I was afraid of. I'll be glad to have the rev. 8 console anyway as I like to have all the various permutations/mods etc. for that console.

A while ago I'd had some email conversations with Marshall (the guy who developed the UltraHDMI mod) and he ruled out the possibilty of the RGB being any different for this console:

"The RCP / VI output that goes into any DAC will always be the same, regardless of the motherboard. All N64s have the same RCP silicon. So you will get the same result no matter what N64 you install Tim's dac onto. The difference in video output comes from the DAC, which you are bypassing/installing your own with the mod."


But what about the possibility of someone down the line developing an RGB dac to fit any N64 that has a customisable colour palett like the NESRGB? Then perhaps you could get the cleaner whites and mimic the bright S-video colours. Maybe one day. I'm still interested in seeing this rev.8 console in action - although from your description, I have a feeling I'll end up continuing to use RGB..

[Guspaz]

The N64 is not a palette-based system, so all you could do is apply a colourspace conversion after the fact.

[andykara2003]

Thanks for the input - so could a colourspace conversion be just as effective and also fairly easy to implement?

[Ikaruga11]

As Link83 said, the Revision 08 models look like a sharpening filter is used.

Hmm that's what I was afraid of. I'll be glad to have the rev. 8 console anyway as I like to have all the various permutations/mods etc. for that console.

A while ago I'd had some email conversations with Marshall (the guy who developed the UltraHDMI mod) and he ruled out the possibilty of the RGB being any different for this console:

"The RCP / VI output that goes into any DAC will always be the same, regardless of the motherboard. All N64s have the same RCP silicon. So you will get the same result no matter what N64 you install Tim's dac onto. The difference in video output comes from the DAC, which you are bypassing/installing your own with the mod."


But what about the possibility of someone down the line developing an RGB dac to fit any N64 that has a customisable colour palett like the NESRGB? Then perhaps you could get the cleaner whites and mimic the bright S-video colours. Maybe one day. I'm still interested in seeing this rev.8 console in action - although from your description, I have a feeling I'll end up continuing to use RGB..

You're right. RGB is exactly the same across all motherboard revisions for the Nintendo 64.

I can't really say for certain that it is a sharpening filter. It could be that the hardware-based blur was toned down. Or the newer video encoder chip is just better. It's one of those three though.

Yeah, I would like to see an RGB mod with MAV-NUS S-Video colors.

[andykara2003]

Nice one. I'll look forward to seeing the thing in action :)

[borti4938]

I'm curious to see some comparison pictures.

Thanks for the input - so could a colorspace conversion be just as effective and also fairly easy to implement?

Viletims DAC board uses a CPLD with 240LEs. A color transformation can be hardly implemented here. In example I implemented a color transformation from RGB to YPbPr into a CPLD which took me 260LEs for four multiplications and some additions.

[andykara2003]

Thanks for chiming in Borti. So instead of having to apply a colour transforation, is there a simpler way of just boosting the clarity of the existing colours (and especially whites) a little?

It's as if the RGB colours have a subtle grey 'veil' over them compared to S-video.

[borti4938]

White is white - all bits in the digital color vectors are set to one here. In the digital way there is no way to further 'boost' them.

What you can try to do with viletims board:
If you have caps inside your RGB cable, just remove them. They are not needed and may reduce the contrast a bit.

Also, you have R49, R50 and R51 on viletims board. These are 270 ohm resistors, which are unfortunately not labeled but luckely the only 270ohm ones.

These resistors together with the R2R ladder gives a Upp of 0.696V, which is below standard (0.714V in US) but normally close enough.
You can replace them with 280ohm resistors which gives you 0.716V.
If you want to overshoot the standard a bit more to saturate earlier, you may also want to use 290ohm or 300ohm resistors (giving you Upp=0.756V)

[andykara2003]

Thank you Borti, much appreciated. I'm using the official Gamecube cables - do they have capacitors in?

EDIT: Apparently they do - I don't want to open the official cables so I'll get a replacement from somewhere and remove the capacitors from that instead.