OSSC Pro

The place for all discussion on gaming hardware
underage
Posts: 16
Joined: Thu Jun 17, 2021 7:53 pm

Re: OSSC Pro

Post by underage »

Fudoh wrote:I'd like to see a CRT that can seemlessly switch between input refresh rates like a Freesync LCD. I don't think that's possible based on the very nature of a CRT versus a sample and hold display.
I'm not going to claim it works, I have no expertise in the subject matter. I just read about it on Blurbusters forum, the Admin there made a post about it, and the CRU creator also made some posts about it, so I took it at face value.
Here are some of the comments that I found on the topic, if it's of any interest to you:

https://forums.blurbusters.com/viewtopi ... 93e#p24850
https://forums.guru3d.com/threads/cru-c ... st-5343792
User avatar
orange808
Posts: 3196
Joined: Sat Aug 20, 2016 5:43 am

Re: OSSC Pro

Post by orange808 »

I think Fudoh was referencing the odd flicker and eye strain that occurs when you use Freesync for playing proper games (with dipping frame rates) on a CRT. Of course, for an emulator, you're fine--because we are using variable refresh as a hack to circumvent the draconian limitations that the OS and drivers impose on devs. The content doesn't really vary the refresh rate.
We apologise for the inconvenience
User avatar
PixelPhoenix
Posts: 31
Joined: Thu Jul 09, 2020 6:12 am

Re: OSSC Pro

Post by PixelPhoenix »

maxtherabbit wrote:
I can't say whether I'm in the key demo or not, but I have 8 consoles going through an extron into an original OSSC and I don't give a fuck about IKEA furniture, backlighting or hiding wires.

Having a metal case would be worth something to me though for physical ruggedness.

To each his own.
And I thought I was the strange one. Glad I'm not alone in that department - my setup is a mess. I use velcro straps for the wiring to make it somewhat tidy, but I don't put much effort in hiding them. I never got into the whole backlighting thing.
User avatar
TooBeaucoup
Posts: 398
Joined: Fri Jun 09, 2017 1:31 am

Re: OSSC Pro

Post by TooBeaucoup »

Elrinth wrote:I bought the shinybow 6x2. But sold it. Have an autoswitcher 16x1 4k, hdr, 4:4:4 which I am extremly satisfied with. Sometimes I need to shut it off as the audio just stops working. But it is very uncommon.
God, I couldn't use 16 if I tried. LOL! I wish I had gone with the 6x2, though!
energizerfellow‌
Posts: 208
Joined: Thu Sep 27, 2018 1:04 am

Re: OSSC Pro

Post by energizerfellow‌ »

underage wrote:
Fudoh wrote:I'd like to see a CRT that can seemlessly switch between input refresh rates like a Freesync LCD. I don't think that's possible based on the very nature of a CRT versus a sample and hold display.
I'm not going to claim it works, I have no expertise in the subject matter. I just read about it on Blurbusters forum, the Admin there made a post about it, and the CRU creator also made some posts about it, so I took it at face value.
Here are some of the comments that I found on the topic, if it's of any interest to you:

https://forums.blurbusters.com/viewtopi ... 93e#p24850
https://forums.guru3d.com/threads/cru-c ... st-5343792
mdrejhon from Blur Busters made an effort post some time back on Arstechnica talking about how VRR is done with variable-length vertical back porch (the end of VBI varies in size) on CRT / FreeSync / Adaptive-Sync / HDMI 2.1, which are effectively interchangeable in how VRR works.

Displaced Gamers also recently released a video about how Atari 2600 developers could alter the vertical blanking interval, complete with code samples from some commercial game releases.
User avatar
Josh128
Posts: 2123
Joined: Thu Jan 16, 2014 9:01 am

Re: OSSC Pro

Post by Josh128 »

Dochartaigh wrote:

Here's my little slice of heaven.

Image

Nice, neat setup there.


Dochartaigh wrote:
Image
Looks impressive at first, but the display is way too high there. I find having about 1/2 to 3/4 of the screen height at eye level to be optimum. Unless this guy has a 5' tall chair to sit in, hes getting some sore neck muscles, lol.

I too would like a nice case, but it will be what it will be. To me, the 5X Pro's SCART would be perfect if it was reversed and the cable went out the back, but its not. SCART heads can be reversed easily enough. Perhaps in a future PCB rev Mike could reverse the SCART, but if he never does thats fine too. I'm happy with it as is. Im still amazed individuals like Mike and Marqs exist.
User avatar
TooBeaucoup
Posts: 398
Joined: Fri Jun 09, 2017 1:31 am

Re: OSSC Pro

Post by TooBeaucoup »

Josh128 wrote:Looks impressive at first, but the display is way too high there. I find having about 1/2 to 3/4 of the screen height at eye level to be optimum. Unless this guy has a 5' tall chair to sit in, hes getting some sore neck muscles, lol.

I too would like a nice case, but it will be what it will be. To me, the 5X Pro's SCART would be perfect if it was reversed and the cable went out the back, but its not. SCART heads can be reversed easily enough. Perhaps in a future PCB rev Mike could reverse the SCART, but if he never does thats fine too. I'm happy with it as is. Im still amazed individuals like Mike and Marqs exist.
Yeah, that TV is up way to high for me. But, if the user likes it, I suppose that's all that matters.

My flat SCART cable works great coming out of my 5X, but I'm sure there will be multiple adapters, dongles and reversed SCART heads available soon for precisely this reason.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

As for remote, wouldn't original OSSC remote work out of the box? I believe it is just one of those universal remotes from China that you program your device to use its commands. I mean this could be 2 devices using one remote.
User avatar
awe444
Posts: 156
Joined: Mon Apr 27, 2015 5:58 am
Location: New York

Re: OSSC Pro

Post by awe444 »

Dochartaigh wrote: Image
What fraction of people in the OSSC Pro’s key demographic would be playing NES games stretched to 16:9 aspect like in the above image? Or is that a 4:3 flat panel
fernan1234
Posts: 2175
Joined: Mon Aug 14, 2017 8:34 pm

Re: OSSC Pro

Post by fernan1234 »

Alright let's cut Dochartaigh some slack already :lol:
For all we know he could have other displays to the side there, and that one is just for anyone who wants to spectate while he plays.

Having all those systems lined up like that does look sweet, this may just be a setup that's more for the pleasure of displaying rather than actual gaming. The OSSC helps a lot for those purposes too.
User avatar
Kez
Posts: 818
Joined: Thu Jul 20, 2017 7:09 am

Re: OSSC Pro

Post by Kez »

Dochartaigh wrote:(picture borrowed from internet)
I don't think the second one is Dochartaigh's.
Anyway we are getting way off topic - my 2 cents on the cable layout is I totally prefer all cables going out the back but it's not a deal breaker for me. Especially as the OSSC has such a good OSD now it's much easier to just tuck it away somewhere. The layout of the OSSC Pro looks good, I think the SCART cable trailing back from the side of the unit will look fine.
Last edited by Kez on Wed Jun 30, 2021 12:06 pm, edited 1 time in total.
DiegoPonga
Posts: 139
Joined: Thu Mar 02, 2017 11:01 am

Re: OSSC Pro

Post by DiegoPonga »

Hey guys, one question on the OSSC Pro.

I am using the v1.6 one, and both SNES and NES have this irregular jittering problem, so my screen is constantly losing signal. Quite an irritating issue.

Just wondering if OSSC Pro would fix this flawlessly or if it's better that I install the dejitter mod Marqs designed for these consoles.
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC Pro

Post by marqs »

orange808 wrote:I think Fudoh was referencing the odd flicker and eye strain that occurs when you use Freesync for playing proper games (with dipping frame rates) on a CRT. Of course, for an emulator, you're fine--because we are using variable refresh as a hack to circumvent the draconian limitations that the OS and drivers impose on devs. The content doesn't really vary the refresh rate.
Yes, a truly varying refresh rate would also mean varying brightness with low-persistence displays.
VEGETA wrote:As for remote, wouldn't original OSSC remote work out of the box? I believe it is just one of those universal remotes from China that you program your device to use its commands. I mean this could be 2 devices using one remote.
OSSC Pro supports the same IR protocol but uses different keycodes by default as it has own dedicated remote. However, keymappings can be redefined just like on the Classic model. It is also possible to copy keycodes from the new remote to the original universal remote so that it can switch between controlling classic and Pro.
DiegoPonga wrote:Hey guys, one question on the OSSC Pro.

I am using the v1.6 one, and both SNES and NES have this irregular jittering problem, so my screen is constantly losing signal. Quite an irritating issue.

Just wondering if OSSC Pro would fix this flawlessly or if it's better that I install the dejitter mod Marqs designed for these consoles.
The new video ADC is more robust with sync irregularities, and based on initial tests (S)NES consoles without dejitter mod should work fine across various displays.
DiegoPonga
Posts: 139
Joined: Thu Mar 02, 2017 11:01 am

Re: OSSC Pro

Post by DiegoPonga »

marqs wrote:(S)NES consoles without dejitter mod should work fine across various displays.
Oh dear, that sounds great.

I guess you already answered you cannot give such information, but just in case... How much would the OSSC Pro cost and when will it be released?

Thanks a lot, marqs. I'm a big fan of your work.
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC Pro

Post by marqs »

Elrinth wrote:Has the FPGA for the OSSC Pro been set in stone now? Which did you decide on and why? Is a release 2022 the year you are aiming for to have some sort of final build for?
DiegoPonga wrote:I guess you already answered you cannot give such information, but just in case... How much would the OSSC Pro cost and when will it be released?
The exact FPGA model is not set in stone yet, but will be selected from 5CEFA5F23 or 5CEFA7F23 variants based on cost and availability (current and projected). These have sufficient amount of logic and performance, and do not require development tool licenses like some higher-tier FPGAs.

I'm not sure what do you mean with 'final' build. With PCB being done HW is nearly final, but the FW is currently just worked towards release condition which is not to be mixed with final. After all it's supposed to be a community project which only starts properly when HW is largely available. We're trying to release at least a small batch this year if possible considering the current component shortages (i.e. don't want to end up selecting between selling at vast overprice or taking a considerable loss).
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

marqs wrote:
Elrinth wrote:Has the FPGA for the OSSC Pro been set in stone now? Which did you decide on and why? Is a release 2022 the year you are aiming for to have some sort of final build for?
DiegoPonga wrote:I guess you already answered you cannot give such information, but just in case... How much would the OSSC Pro cost and when will it be released?
The exact FPGA model is not set in stone yet, but will be selected from 5CEFA5F23 or 5CEFA7F23 variants based on cost and availability (current and projected). These have sufficient amount of logic and performance, and do not require development tool licenses like some higher-tier FPGAs.

I'm not sure what do you mean with 'final' build. With PCB being done HW is nearly final, but the FW is currently just worked towards release condition which is not to be mixed with final. After all it's supposed to be a community project which only starts properly when HW is largely available. We're trying to release at least a small batch this year if possible considering the current component shortages (i.e. don't want to end up selecting between selling at vast overprice or taking a considerable loss).
As for cost, it depends on your margin. EEVblog economics of selling your own hardware episode mentioned that most manufacturers in industry and single or low count teams all use 2.5 times multiplier, meaning if it costs you 100$ you should sell it for at least 250$ to be able to "stay in business". Do you personally follow such number or similar? since it is open source, do you consider having so minimal profit and accept it instead of getting what you should get? I guess these questions determine how the retail price will be.
User avatar
bobrocks95
Posts: 3460
Joined: Mon Apr 30, 2012 2:27 am
Location: Kentucky

Re: OSSC Pro

Post by bobrocks95 »

marqs wrote:
Elrinth wrote:Has the FPGA for the OSSC Pro been set in stone now? Which did you decide on and why? Is a release 2022 the year you are aiming for to have some sort of final build for?
DiegoPonga wrote:I guess you already answered you cannot give such information, but just in case... How much would the OSSC Pro cost and when will it be released?
The exact FPGA model is not set in stone yet, but will be selected from 5CEFA5F23 or 5CEFA7F23 variants based on cost and availability (current and projected). These have sufficient amount of logic and performance, and do not require development tool licenses like some higher-tier FPGAs.

I'm not sure what do you mean with 'final' build. With PCB being done HW is nearly final, but the FW is currently just worked towards release condition which is not to be mixed with final. After all it's supposed to be a community project which only starts properly when HW is largely available. We're trying to release at least a small batch this year if possible considering the current component shortages (i.e. don't want to end up selecting between selling at vast overprice or taking a considerable loss).
I think you definitely have enough interest to do a small early run that is more expensive. So long as you're up front about parts shortages and the small run meaning that the price will go down on future batches, I can imagine it would sell out and early adopters would be lined up.
PS1 Disc-Based Game ID BIOS patch for MemCard Pro and SD2PSX automatic VMC switching.
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC Pro

Post by marqs »

VEGETA wrote:As for cost, it depends on your margin. EEVblog economics of selling your own hardware episode mentioned that most manufacturers in industry and single or low count teams all use 2.5 times multiplier, meaning if it costs you 100$ you should sell it for at least 250$ to be able to "stay in business". Do you personally follow such number or similar? since it is open source, do you consider having so minimal profit and accept it instead of getting what you should get? I guess these questions determine how the retail price will be.
For me personally the project is just a hobby so no business to run or salaries to pay, but I have a royalty compensation scheme with sellers I work with. Obviously selling and shipping require more day-to-day work and carries financial risks so there needs to be some price margin, but the total should end up less than 2.5x manufacturing cost.
Sabin
Posts: 13
Joined: Sun Nov 16, 2014 7:04 pm

Re: OSSC Pro

Post by Sabin »

marqs is there anything you can discuss about the scaler/hdmi port at this stage?
Specifically I was wondering about the refresh rate conversion part of the scaler.

I'm wondering if it's possible to benefit from 144hz monitors (due to the lower scanout of 144hz compared to 60hz) and what refresh rates would you be targeting?
Also what HDMI version are you planning to support?

Appreciate any answer and thanks for your hardwork. I look forward to ordering a ton of these when it drops just like I told you when we met at Retrocreates :D
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

marqs wrote:
VEGETA wrote:As for cost, it depends on your margin. EEVblog economics of selling your own hardware episode mentioned that most manufacturers in industry and single or low count teams all use 2.5 times multiplier, meaning if it costs you 100$ you should sell it for at least 250$ to be able to "stay in business". Do you personally follow such number or similar? since it is open source, do you consider having so minimal profit and accept it instead of getting what you should get? I guess these questions determine how the retail price will be.
For me personally the project is just a hobby so no business to run or salaries to pay, but I have a royalty compensation scheme with sellers I work with. Obviously selling and shipping require more day-to-day work and carries financial risks so there needs to be some price margin, but the total should end up less than 2.5x manufacturing cost.
this changes the entire equation, maybe you will be ok with just 50$ profit per unit to sustain the production and serve the community. I assume people in China will make cheaper units than you eventually such as original OSSC.

Now it can be reasonable to get 110$ or 230$ FPGA while still selling it for 400-500$. ISL51002 is not cheap if you want the 165MHz version, I saw 110MHz version for about 15$ though but it can't handle 1080p input. I assume no one needs such high bandwidth analog video, even PS3 has HDMI output so that you don't need its analog component video. Getting the 110 MHz version will not affect any retro gamer except if anyone needs Graphics RGB inputs which are very high pixel clock, even 1280x1024@60fps is doable for 110 Mhz version.

Best of wishes for you friend, I hope I can get an OSSC Pro when time comes.

Edit: I read you have s-video and composite support but ISL51002 doesn't seem to support them. how are they implemented? what about their sync?
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC Pro

Post by marqs »

Sabin wrote:I'm wondering if it's possible to benefit from 144hz monitors (due to the lower scanout of 144hz compared to 60hz) and what refresh rates would you be targeting?
Also what HDMI version are you planning to support?
Currently 60Hz is supported up to 2560x1440 output, and 100/120Hz presets are made for 1920x1080 and 1280x720. It's possible to support even higher refresh rates if resolution is dropped from 1080p, but it has very little benefit for 50/60Hz sources. I see BFI as the primary use case, and for that 2x refresh rate (locked) should be used. The board utilizes 300MHz HDMI 1.4 transmitter.
VEGETA wrote:this changes the entire equation, maybe you will be ok with just 50$ profit per unit to sustain the production and serve the community. I assume people in China will make cheaper units than you eventually such as original OSSC.

Now it can be reasonable to get 110$ or 230$ FPGA while still selling it for 400-500$. ISL51002 is not cheap if you want the 165MHz version, I saw 110MHz version for about 15$ though but it can't handle 1080p input. I assume no one needs such high bandwidth analog video, even PS3 has HDMI output so that you don't need its analog component video. Getting the 110 MHz version will not affect any retro gamer except if anyone needs Graphics RGB inputs which are very high pixel clock, even 1280x1024@60fps is doable for 110 Mhz version.
I'm not too worried about Chinese versions unless they can do better quality at lower price. If the product is priced reasonably at launch, they are also less likely to enter the market early on since there's not enough gain to balance the risk (of not knowing whether product will be successful or not in long run).

About FPGA pricing, I'm not sure where people are getting ideas it'd cost more than $100 per unit. For ISL51002 I deliberately chose 165MHz version even though not everyone benefits from it. The price difference is not massive and otherwise the spec would be inferior to classic model. ISL51002 doesn't have PAL/NTSC decoding, but it should be possible to run CVBS/S-video through its ADC and do decoding on FPGA. As mentioned earlier, I can provide a free board for anyone familiar with the subject and willing to develop the feature.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

I'm not too worried about Chinese versions unless they can do better quality at lower price.
Yes but these Chinese manufacturers are ok with very little profit margin, way less than anyone can handle. but as you said, early on they won't jump in.
About FPGA pricing, I'm not sure where people are getting ideas it'd cost more than $100 per unit.
you posted 2 models, and I checked them using Octopart (and distro sites like Digikey and mouser) and seem to give the prices as I posted earlier. Maybe you can get them cheaper directly from Manufacturer but still won't be too much difference especially if you calculate separate shipping and handling fees. I don't think you search for these stuff on Aliexpress. Notice that I posted prices based on small quantities due to not knowing the production batch quantity.

For ISL51002 I deliberately chose 165MHz version even though not everyone benefits from it. The price difference is not massive and otherwise the spec would be inferior to classic model.
There was ISL98001 which seems similar and a lot cheaper, but it doesn't give you sync measurements as much as ISL51002. Also, for ISL51002, the 165MHz seems the only supported version from manufacturer, the others are discontinued = bad long term choice, while 165MHz version is good choice.
ISL98001 has 170Mhz version which is 25-35$ while ISL51002 165MHz version is about 45-60$ or so. If you don't need sync measurement and can do them elsewhere, then ISL98001 should be better due to price.
ISL51002 doesn't have PAL/NTSC decoding, but it should be possible to run CVBS/S-video through its ADC and do decoding on FPGA
You would need something like TVP5146M2 on a separate module connected to your IO expansion board which delivers digital YC 20-bits signal, I assume your FPGA scaler IP handles 20-bit YC properly. if it handles 8-bit ITU-R output which is famous then getting cheaper ADCs is viable. Extra module shouldn't be costly for S-video and CVBS IMO.
User avatar
matt
Posts: 567
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Re: OSSC Pro

Post by matt »

VEGETA wrote:this changes the entire equation, maybe you will be ok with just 50$ profit per unit to sustain the production and serve the community. I assume people in China will make cheaper units than you eventually such as original OSSC.
Even with the orginal OSSC, the price difference wasn't significant. When I bought mine from VGP, the Chinese ones werent much cheaper and the shipping time from Ireland vs China was shorter. I do feel that supporting the original creator is important, but it wouldn't have made sense to buy the Chinese version even if I didn't have that moral perspective.
User avatar
Dr. Claw
Posts: 30
Joined: Thu Jul 16, 2020 4:14 pm

Re: OSSC Pro

Post by Dr. Claw »

matt wrote:
VEGETA wrote:this changes the entire equation, maybe you will be ok with just 50$ profit per unit to sustain the production and serve the community. I assume people in China will make cheaper units than you eventually such as original OSSC.
Even with the orginal OSSC, the price difference wasn't significant. When I bought mine from VGP, the Chinese ones werent much cheaper and the shipping time from Ireland vs China was shorter. I do feel that supporting the original creator is important, but it wouldn't have made sense to buy the Chinese version even if I didn't have that moral perspective.
there's also the matter of the little things that are off-spec on the non-VGP models. For example, I don't think those OSSC cases fit the non-VGP models at all.
The non-VGP ones also have a presence on eBay too, which might be easier for a lot of people.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

Even with the orginal OSSC, the price difference wasn't significant. When I bought mine from VGP, the Chinese ones werent much cheaper and the shipping time from Ireland vs China was shorter. I do feel that supporting the original creator is important, but it wouldn't have made sense to buy the Chinese version even if I didn't have that moral perspective.
Original one is about 230$ including shipping to Jordan while Aliexpress one was about 100-110$ including shipping to Jordan. Huge difference. You've got to know that Chinese manufacturers are ok with very little margins, therefore if they gained 20$ profit per unit they might be ok with it. They get manufacturing + ICs very cheaply locally too. You simply cannot compete with them in this.

I disagree with "moral" perspective of yours simply because the original creator intentionally made it open source knowing full well that others will manufacture and sell it. It is good to support original creator but this doesn't make you more moral than others :D

All this can be wrong only if the original creator included the "non-commercial" part in the open source license. Yes! this thing exist! you can make your project fully open source but still prevent anyone from making production units and sell them! you can also make it "non-derivative" but OSSC is not any of this.
User avatar
Unseen
Posts: 723
Joined: Sun May 25, 2014 8:12 pm
Contact:

Re: OSSC Pro

Post by Unseen »

VEGETA wrote:Yes! this thing exist! you can make your project fully open source but still prevent anyone from making production units and sell them! you can also make it "non-derivative" but OSSC is not any of this.
There are some that would disagree with that statement. Maybe you were thinking of Creative Commons BY-NC/BY-ND etc.?
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

Unseen wrote:
VEGETA wrote:Yes! this thing exist! you can make your project fully open source but still prevent anyone from making production units and sell them! you can also make it "non-derivative" but OSSC is not any of this.
There are some that would disagree with that statement. Maybe you were thinking of Creative Commons BY-NC/BY-ND etc.?
yes I meant those licenses which are part of open source culture. Please note that there is no central power or government which dictates or owns such terms.

So you can open source your work and slam in any of those CC licenses and will be ok. now anyone else trying to sell it, he would be wrong not just immoral.
Nrg
Posts: 45
Joined: Sun Aug 30, 2015 8:36 pm

Re: OSSC Pro

Post by Nrg »

VEGETA wrote:
ISL51002 doesn't have PAL/NTSC decoding, but it should be possible to run CVBS/S-video through its ADC and do decoding on FPGA
You would need something like TVP5146M2 on a separate module connected to your IO expansion board which delivers digital YC 20-bits signal, I assume your FPGA scaler IP handles 20-bit YC properly. if it handles 8-bit ITU-R output which is famous then getting cheaper ADCs is viable. Extra module shouldn't be costly for S-video and CVBS IMO.
Note that none of those off-the-shelf pal/ntsc video decoder ICs allow doing pixel perfect sampling of retro consoles using various custom resolutions. All those ICs give you (for PAL) 720 or 768 pixels per scanline, which isn't optimal. When you do the decoding manually on the FPGA it can be done pixel-perfect.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: OSSC Pro

Post by VEGETA »

Nrg wrote:
VEGETA wrote:
ISL51002 doesn't have PAL/NTSC decoding, but it should be possible to run CVBS/S-video through its ADC and do decoding on FPGA
You would need something like TVP5146M2 on a separate module connected to your IO expansion board which delivers digital YC 20-bits signal, I assume your FPGA scaler IP handles 20-bit YC properly. if it handles 8-bit ITU-R output which is famous then getting cheaper ADCs is viable. Extra module shouldn't be costly for S-video and CVBS IMO.
Note that none of those off-the-shelf pal/ntsc video decoder ICs allow doing pixel perfect sampling of retro consoles using various custom resolutions. All those ICs give you (for PAL) 720 or 768 pixels per scanline, which isn't optimal. When you do the decoding manually on the FPGA it can be done pixel-perfect.
but how to do it in fpga? you would need first an ADC but it will spit continuous digital data, so probably you would need to start decoding at each v_sync start. So this I assume would need a lot of extra code beyond the scaler IP itself. to be honest, cvbs is not really important as long as RGB\Component exist but S-video can be useful. Still, both are not needed as long as component exists.

I suggested ADV7800 (a newer alternative is ADV7403) which supports all analog video types in one IC, I assume it does handle stuff properly since in its datasheet has detection options for 240p, 525i, etc... original designer choose ISL51002 which is very good in terms of sync detection and measurements but has the downside of not capable of decoding CVBS and S-video. Compromise is engineering.
User avatar
marqs
Posts: 1034
Joined: Sat Dec 15, 2012 12:11 pm
Location: Finland

Re: OSSC Pro

Post by marqs »

VEGETA wrote:
About FPGA pricing, I'm not sure where people are getting ideas it'd cost more than $100 per unit.
you posted 2 models, and I checked them using Octopart (and distro sites like Digikey and mouser) and seem to give the prices as I posted earlier. Maybe you can get them cheaper directly from Manufacturer but still won't be too much difference especially if you calculate separate shipping and handling fees. I don't think you search for these stuff on Aliexpress. Notice that I posted prices based on small quantities due to not knowing the production batch quantity.
To give you an example, years ago in my day job we were checking viability of development of a FPGA-based acceleration card and the process included negotiations with local Altera/Intel distributor. The quoted prices were around 20-30% of Digikey/Mouser if I remember correctly, assuming a yearly quota would be met. Those were higher-tier Arria FPGAs, though and we're not getting quite as good deal here, but you should still not take Digikey/Mouser FPGA pricing as reference for batch production.
VEGETA wrote:but how to do it in fpga? you would need first an ADC but it will spit continuous digital data, so probably you would need to start decoding at each v_sync start. So this I assume would need a lot of extra code beyond the scaler IP itself. to be honest, cvbs is not really important as long as RGB\Component exist but S-video can be useful. Still, both are not needed as long as component exists.
CVBS/S-video would be fed into 1/2 channels of ISL51002 which would do line-locking and digitization just like for RGBS. The resulting signal obviously would not be directly usable as chroma is encoded in PAL/NTSC so you'd need to extract color burst, lock to it and finally do some DSP to decode color data. Not entirely trivial but should be still possible even with limitations of the ADC and FPGA.
VEGETA wrote:I suggested ADV7800 (a newer alternative is ADV7403) which supports all analog video types in one IC, I assume it does handle stuff properly since in its datasheet has detection options for 240p, 525i, etc... original designer choose ISL51002 which is very good in terms of sync detection and measurements but has the downside of not capable of decoding CVBS and S-video. Compromise is engineering.
To my understanding ADV740x is a family of basic CVBS/RGB decoders (later models also included digital data input port) while ADV780x are mostly similar but have added SDRAM interface for TBC, comb filtering etc. Then there is also the oddball budget model ADV7181D which is most recent of the bunch and thus possibly worth checking out if you can look past its limitations. Even if datasheet mentions 240p it doesn't guarantee the chip works with all sync types and quircks. For example, my old AE700 projector from 15+ years ago has ADV7402 in it and it didn't work with all SNES models (later ones don't have serration pulses). Whether the problem was in chip configuration rather than in its capability is something I don't know, but I'd do some testing before jumping on using any one chip.
Post Reply