OSSC (DIY video digitizer & scandoubler)

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fandangos
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Re: OSSC (DIY video digitizer & scandoubler)

Post by fandangos »

nmalinoski wrote: There's no risk of damaging the OSSC by flipping that switch; video mode changes are inherent to video technology, such as the numerous PS1 and PS2 games that switch between 240p gameplay and 480i menus, the switch between RGBS and RGsB in the handful of PS2 games that support 480p+, and the Xbox with its 480i menus (assuming an original dash) and its handful of games that support 480p+.

What you might have an issue with is the OSSC's lack of automatic mode detection and switching. I believe you have to start the Dreamcast in RGBS mode and then flip the switch to activate RGBHV mode during the white SEGA licensing screen, after which the game will switch from 480i to 480p.

The problem with using the straight VGA cable, then, is that you would need to manually switch the OSSC's input to AV3 RGBS so you can get a visual cue (the licensing screen) to flip the switch, then manually switch the OSSC's input to AV3 RGBHV to play the game. If you still had the GD-ROM drive installed, you could use that as an aural cue and just leave the OSSC on AV3 RGBHV. Then again, I'm not sure what facilities, if any, your USB GDROM has for launching games in RGBHV mode.

In my case, I have a BeharBros Toro, which I have configured to output RGBS, and it's connected to my OSSC via SCART. With this setup, I always get RGBS out of the Dreamcast, so I can get the visual cue and flip the Toro's mode switch without futzing with the OSSC.
That's great to hear.
I think I'll do the internal mod for now since it's easy, inexpensive and I can use properly shielded cables from one of my CRT monitors.

I actually have the official scart cable for the dreamcast.
As I can see in your setup the Torobox when receiving H and V sync will combine those for Csync?
Is that the reason you have RGBS all the time?

What I'm thinking here is, if I use the Scart cable, just add the switch to toggle VGA mode is the OSSC capable of working with 480p that way?
I guess there might be a situation with Sync since 31Khz standard uses H and V sync instead of Csync.
nmalinoski
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Re: OSSC (DIY video digitizer & scandoubler)

Post by nmalinoski »

fandangos wrote:I actually have the official scart cable for the dreamcast.
As I can see in your setup the Torobox when receiving H and V sync will combine those for Csync?
Is that the reason you have RGBS all the time?

What I'm thinking here is, if I use the Scart cable, just add the switch to toggle VGA mode is the OSSC capable of working with 480p that way?
I guess there might be a situation with Sync since 31Khz standard uses H and V sync instead of Csync.
Yes, the Toro has a sync combiner to convert the RGBHV from the Dreamcast into RGBS, which is needed to use the Toro's SCART output. I leave my Toro in RGBS mode and use SCART because a) of the aforementioned benefit of having that visual cue to flip the video mode switch, and b) I intend to add an automatic SCART switch to my setup later this year, and the Toro's SCART output would be easier to integrate into that kind of setup.

You would not be able to use the official SCART cable to get 480p. The Dreamcast only outputs 480p in RGBHV mode, and SCART was not designed to accommodate the separate horizontal and vertical sync signals. You would need to add a sync combiner circuit in addition to the mode switch.

Also, the kHz 'standard' has no bearing on use of composite or separate sync; you should be able to use either method for any combination of resolution and refresh rate. It's possible that, as is rumored with the Xbox, the hardware intentionally restricts native RGB SCART output to standard-definition video (480i max) as to not damage SD-only CRT televisions that do not and/or cannot understand 480p. There is no physical or technical limitation preventing 480p (or even 720i/p or 1080i/p) RGBS from being transmitted over a SCART cable, as long as the receiving end (like a TV or OSSC) can understand the signal.

Personally, I wouldn't bother modifying that official cable, because it's not worth the effort when you can simply buy a preassembled product, like the Toro, or even a cable (like those made by thefoo.83 on eBay), that would ostensibly do the job correctly out of the box; not to mention you would be destroying what is now arguably a collector's item. I would hang onto the official SCART cable, either displaying it on a shelf, or reselling it to someone else, and saving your money for a Toro or a VGA cable with a sync combiner (if you intend to use your Dreamcast on an old CRT) or for the upcoming DreamcastHDMI mod.
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orange808
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Re: OSSC (DIY video digitizer & scandoubler)

Post by orange808 »

Can we try forcing Freesync on with an automated EDID edit?

Edit: Would need to be an unofficial firmware. Many displays don't support it with a wide range of refresh rates. And, forcing it on with a display that doesn't officially implement it could cause issues.
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thebigcheese
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Re: OSSC (DIY video digitizer & scandoubler)

Post by thebigcheese »

orange808 wrote:I would be very interested in the link for the television deinterlacing database.
Not aware of any deinterlacing database, but rtings.com does a lot of reviews that include input lag numbers for a lot of TVs. If you happen to have a CRT lying around and a way to split your signal, it's also pretty easy to set up a camera and measure the difference yourself. Alternatively, you could get a less scientific number by taking a video of the screen with your hand and controller in front of it and count the frames between when you hit the button and when an action happens on screen. You could then compare between progressive sources and interlace sources. I haven't noticed any particular difference on my TV between the two, but it could be different on yours.
thebigcheese
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Re: OSSC (DIY video digitizer & scandoubler)

Post by thebigcheese »

Konsolkongen wrote:
thebigcheese wrote:
Yes, but it would do that with or without the OSSC, which was my point. The OSSC does not add any additional lag to interlaced sources, either. It just digitizes them. So OP can just plug in to their TV without an OSSC and measure it. Or look up ratings online.
But I can’t measure the lag without the OSSC. Just wanted to know if someone had already measured the deinterlacelag for these fairly popular TVs with their OSSC. Would save me the (small) hassle of buying the components and measuring myself :)
But that's my point. If you are using passthrough with 480i, there is no difference if you have the OSSC hooked up or not. OSSC doesn't add any lag, so you can measure with the OSSC in the signal path and it should be basically exactly the same as without it. The difference would be in the order of hundreths of a second, IIRC. Significantly less than a frame or even half a frame for sure. TL;DR: use the OSSC, get a number, and it will be the same as without the OSSC.
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Xyga
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Xyga »

@orange808: honestly in over a decade the only place I have read about deinterlacing lag measurements is here, and that was essentially from Fudoh for external scalers.
Not a single reviewer/website ever bothered with testing specifically this on monitors and TVs, and now it's too ancient, beyond overniche.
I guess the only hope would be a lot of people to beg Rtings to add this to their lag testing routine.
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bobrocks95
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Re: OSSC (DIY video digitizer & scandoubler)

Post by bobrocks95 »

thebigcheese wrote:
Konsolkongen wrote:
thebigcheese wrote:
Yes, but it would do that with or without the OSSC, which was my point. The OSSC does not add any additional lag to interlaced sources, either. It just digitizes them. So OP can just plug in to their TV without an OSSC and measure it. Or look up ratings online.
But I can’t measure the lag without the OSSC. Just wanted to know if someone had already measured the deinterlacelag for these fairly popular TVs with their OSSC. Would save me the (small) hassle of buying the components and measuring myself :)
But that's my point. If you are using passthrough with 480i, there is no difference if you have the OSSC hooked up or not. OSSC doesn't add any lag, so you can measure with the OSSC in the signal path and it should be basically exactly the same as without it. The difference would be in the order of hundreths of a second, IIRC. Significantly less than a frame or even half a frame for sure. TL;DR: use the OSSC, get a number, and it will be the same as without the OSSC.
Not sure how you're missing the actual question, which is "has anyone measured the lag in 480i vs 480p or do I need to get the stuff so I can with my OSSC?" We're all aware the OSSC is not adding lag.
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Significantly less than a frame or even half a frame for sure. TL;DR: use the OSSC, get a number, and it will be the same as without the OSSC.
these kids today - tssss - - - - don't even remember the days when video processors were sold in order to minimize processing delay OTHERWISE introduced by the TVs on their own.

In other words: almost every TV or display out there has considerably more lag for interlaced sources than for progressive ones. And since - unfortunately - 15khz signals are almost always handled as interlaced, this affects 240p sources as well.
EthicalShooter
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Re: OSSC (DIY video digitizer & scandoubler)

Post by EthicalShooter »

Got an idea for a more powerful OSSC, with a more powerful FPGA to give it enough RAM to store more lines, and a faster CPU to (optionally) do basic scaling and/or windowboxing.

Considering that monitors have to scale the OSSC's image anyway, it wouldn't really take any longer for the OSSC to do it itself (probably less time due to already having the needed info in RAM and not having to re-receive the signal line-by-line). Besides, pre-scaling 960p to 1080p would dramatically increase compatibility.

According to my math, if it's done the fastest way possible, windowboxing 960p in a 1080p window would add something like 1.86 milliseconds of input lag at the top left, and theoretically absolutely no lag at the bottom right (so like .93 milliseconds average).

I think it would be even less time for a bilinear scale, due to the process itself being simple and only requiring 2 (input) lines to be buffered at a time, and having to wait less time to start outputting because the extra intermediate lines would stall the output frequency from catching up to the input frequency.

Hell, could a bilinear scaling option be implemented on the current OSSC's hardware?
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BuckoA51
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Re: OSSC (DIY video digitizer & scandoubler)

Post by BuckoA51 »

Generally it's not scaling that adds the input lag it's processing.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Been a while since I asked this - Does anyone have any capture card recommendations for the OSSC?

My two requirements are that it works with all modes of the OSSC including on the SNES, and that it has 4:4:4 chroma at 1080p. 4k capture is a bonus, but not a requirement. I've been looking for something reasonable that can do 4:4:4 for a while now though.

Thanks!
brittonal
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Re: OSSC (DIY video digitizer & scandoubler)

Post by brittonal »

Has any shared their PS1 5x profiles in here yet? I'm looking to compare mine. I used the 240p test suite to do 320x240 so far, but it looks like the PS1 may have a variety of resolutions for main gameplay.

======================
DELL U3011
OSSC 1.6
FIRMWARE: V0.81
PLAYSTATION: 320X240 ??[256X240|384X240|512X240|640X240]??
PROFILE: 3
======================

======================
VIDEO IN PROC.
======================
VIDEO LPF -> 9MHZ (SDTV)
R/PR GAIN -> 40
G/Y GAIN -> 40
B/PB GAIN -> 40
======================
SAMPLING OPT.
======================
SAMPLING PHASE -> 168 DEGREES
ADVANCED TIMING -> 320X240
HORIZONTAL BACKPORCH -> 48
HORIZONTAL SAMPLERATE -> 427
======================
SYNC OPT.
======================
ANALOG SYNC LPF -> 2.5 MHZ (MAX)
======================
OUTPUT OPT.
======================
TX MODE -> HDMI
LINE5X FORMAT -> 1600x1200
LINE5X MODE -> 320X240
240p/288p -> LINE5X
======================
POST PROC.
======================
SCALINES -> MANUAL
SCANLINE STR -> 50%
HYBRID SCANLINE STR -> 50%
SCANLINE METHOD -> MULTIPLICATION
======================
COMPATIBILITY
======================

======================
AUDIO OPTIONS
======================

======================
SETTINGS OPTIONS
======================
INTIAL INPUT -> AV1: RGBS
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FBX
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Re: OSSC (DIY video digitizer & scandoubler)

Post by FBX »

Jademalo wrote:Been a while since I asked this - Does anyone have any capture card recommendations for the OSSC?

My two requirements are that it works with all modes of the OSSC including on the SNES, and that it has 4:4:4 chroma at 1080p. 4k capture is a bonus, but not a requirement. I've been looking for something reasonable that can do 4:4:4 for a while now though.

Thanks!
A lot of us got used Vision E1S cards from ebay. For dirt cheap ($120) you get all that you listed with the exception of 4K support.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

FBX wrote:A lot of us got used Vision E1S cards from ebay. For dirt cheap ($120) you get all that you listed with the exception of 4K support.
Thanks for the recommendation!
I'm in the UK, and after a quick look there's gonna be a whack ton of shipping and import. £100 + £45 shipping + £20 VAT + ~£8 Brokerage, suddenly it's up near £175. I'm a bit loathe to pay double just on shipping and import. Definitely going to keep my eye on it though.

Are there any good USB3 cards that can do 4:4:4 and every OSSC mode? 4k as a bonus, but not a neccesity. Just I'm a bit tight on PCIe slots, and I would rather something USB if at all possible.
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FBX
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Re: OSSC (DIY video digitizer & scandoubler)

Post by FBX »

Jademalo wrote:
Are there any good USB3 cards that can do 4:4:4 and every OSSC mode? 4k as a bonus, but not a neccesity. Just I'm a bit tight on PCIe slots, and I would rather something USB if at all possible.
USB is going to be a lot harder to find with all those features. You might try asking Bob (RetroRGB), as he's tried a number of different solutions.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

FBX wrote:USB is going to be a lot harder to find with all those features. You might try asking Bob (RetroRGB), as he's tried a number of different solutions.
Alright, I'll shoot him a message.
Thanks for the help!
NYI
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Re: OSSC (DIY video digitizer & scandoubler)

Post by NYI »

Have a question for you guys regarding sync voltage. Here is my setup:

Extron Crosspoint output via BNC to VGA cable -----> Extron RGB 192v ----> RGsB ----- > AV2

Using this setup, I'm wondering if the RGB 192 is outputting TTL level voltage to the sync signal it is sending on top of the green signal?

The reason I am not using VGA direct into AV3 is that PS2/Saturn output looks noisy with it. (No LPF :()
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Are there any good USB3 cards that can do 4:4:4 and every OSSC mode? 4k as a bonus, but not a neccesity. Just I'm a bit tight on PCIe slots, and I would rather something USB if at all possible.
for snapshots, yes - for 1080p60 video, no. This is a bandwith issue with USB 3.0 and I don't hink there are USB 3.1 units anywhere.

The Epiphan DVI2USB (sub 200 EUR on ebay) works great with anything I tried yet, but in 4:4:4 you're hitting a bandwith limitation of about 40fps in 1080p. If you capture directly into x264 instead (in 4:2:2 or 4:2:0) you get your 1080p at 60fps of course.

The internal version of the Epiphan doesn't have this limitation, but it's a bit harder to find than the Datapath ones.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Fudoh wrote:for snapshots, yes - for 1080p60 video, no. This is a bandwith issue with USB 3.0 and I don't hink there are USB 3.1 units anywhere.

The Epiphan DVI2USB (sub 200 EUR on ebay) works great with anything I tried yet, but in 4:4:4 you're hitting a bandwith limitation of about 40fps in 1080p. If you capture directly into x264 instead (in 4:2:2 or 4:2:0) you get your 1080p at 60fps of course.

The internal version of the Epiphan doesn't have this limitation, but it's a bit harder to find than the Datapath ones.
Alright, thank you!
How exactly do the Magewell ones work? They seem to be advertising 1080p60/4:4:4 and even 4k 4:4:4 over USB
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Epiphan too, but you mind find limitations that restrict either framerate, pixel resolution or color resolution for certain combinations in the fine print.
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Magewell's techspecs:

- Support for up to 4096×2160 4:4:4 60fps input signals
- 1920×1080 YUY2 (up to 90fps)
- Support for NV12 & l420 4:2:0 8-bit (up to 4096×2160)
- Support for YUY2 & UYVY4:2:2 8-bit (up to 4096×2160)
- Support for RGB24 & RGB32 4:4:4 8-bit (up to 2048×2160) with no mention of framerate.
- The default capture formats are YUY2 & NV12 (which aren't 444)
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Aaaah, that's sneaky.
Thanks for clarifying that though, much appreciated. Do you know of any good sources for used Vision E1Ses in the EU, or am I gonna have to bite the bullet and shell out a ton for import?
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

they tend to show up here as well. I have imported one from the US and have another one from ebay Germany (at something like 80 EUR). The E1S has no audio capture though and mine won't run on a H110 chipset mainboard that I got.

I now have a Thunderbolt 3 eGPU box (the small one from Zotac), so I can use the E1S on a Hades Canyon NUC.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Oh, thanks for the tip about audio, that might be a dealbreaker. I haven't got a mixing desk or anything that could mitigate that at present, and getting audio out of HDMI without noise has been a nightmare for me. Ground loops for days.

I swear in 10-15 years when bandwidth isn't an issue, chroma subsampling is going to be this generation's interlacing, lol. Obviously nowhere near as bad, but still. (And yes I know NTSC and PAL did it =p)

Regardless, I'll keep my eye out. Thanks again!
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Oh, thanks for the tip about audio, that might be a dealbreaker. I haven't got a mixing desk or anything that could mitigate that at present, and getting audio out of HDMI without noise has been a nightmare for me. Ground loops for days.
cleanest way would be a HDMI to DVI+SPDIF breakout box and then a SPDIF to USB audio capture dongle.
I swear in 10-15 years when bandwidth isn't an issue, chroma subsampling is going to be this generation's interlacing.
do you see it going away ? As long as every video platform, streaming service and physical media (BD or UHD-BD) strictly uses 4:2:0 codecs, there's just to little motivation to offer 4:4:4 to customers. 4:4:4 is nice for analysis and for snapshots, but for actual video ? not really...
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Fudoh wrote:
I swear in 10-15 years when bandwidth isn't an issue, chroma subsampling is going to be this generation's interlacing.
do you see it going away ? As long as every video platform, streaming service and physical media (BD or UHD-BD) strictly uses 4:2:0 codecs, there's just to little motivation to offer 4:4:4 to customers. 4:4:4 is nice for analysis and for snapshots, but for actual video ? not really...
I mean, you could argue the same could be said in the early 2000s about interlaced video - even into the early HD days interlaced 1080p was the standard. Heck, plenty of places still use it as a standard now. I feel like it will eventually transition in that direction once we hit 8k video, there wont be as much motivation to keep increasing the base resolution. Maybe once we start properly using bt.2020 as standard everywhere it might delay it, but I don't know.
Consoles and PCs all use 4:4:4 paths, it's really just video. I expect it to go in that direction eventually.
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

Consoles and PCs all use 4:4:4 paths
that's crumbling right now. With HDR many resolution/refresh rate combos are forced to reduce the color sampling. The new 144Hz HDR 4K gaming monitors can only operate at their peak specs at 4:2:2. Many PS4 Pro users don't realize either that their console is reducing to 4:2:2 in order to keep the HDMI bandwith within the TV's specs.

I'm not defending color subsampling in any way, just stating that it's getting worse atm before it'll get better.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Fudoh wrote:that's crumbling right now. With HDR many resolution/refresh rate combos are forced to reduce the color sampling. The new 144Hz HDR 4K gaming monitors can only operate at their peak specs at 4:2:2. Many PS4 Pro users don't realize either that their console is reducing to 4:2:2 in order to keep the HDMI bandwith within the TV's specs.

I'm not defending color subsampling in any way, just stating that it's getting worse atm before it'll get better.
Isn't that mostly because of HDMI cable limits?
I know 2.1 is capable of doing 10bpc RGB 4k HDR, hopefully in a couple of years when that's standard companies will use it on newer hardware.

Hopefully that gets adopted fast enough before it becomes a problem.
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Fudoh
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Fudoh »

me too, but the new HDMI 2.1 specs include the "A" and "B" nomination of all the high bandwith modes, which kinda supports and endorses manufacturer to use compression. Doesn't make it any easier.
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Jademalo
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Re: OSSC (DIY video digitizer & scandoubler)

Post by Jademalo »

Damn, that's annoying D:
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