OSSC (DIY video digitizer & scandoubler)

[BazookaBen]

So I've made custom VGA cables for all my RGB consoles. They have composite sync on the H pin. Would that work with the VGA input on this device?

[Hoagtech]

So I've made custom VGA cables for all my RGB consoles. They have composite sync on the H pin. Would that work with the VGA input on this device?

Holy cow man. You actually made VGA cables for all your RGB DEVICES? Impressive to say the least

[BazookaBen]

So I've made custom VGA cables for all my RGB consoles. They have composite sync on the H pin. Would that work with the VGA input on this device?

Holy cow man. You actually made VGA cables for all your RGB DEVICES? Impressive to say the least

They're really short, just a few inches. Terminates in VGA female and stereo RCA, then I just connect a normal VGA to BNC cable when connecting to my PVM. It's great being able to avoid using SCART completely

... but they're not super high quality. Connectors are held in place with hot glue. I'm going to make better versions in the future after I find some good reading on how to make strong DIY cables.

[marqs]

One silly question, I want to build a tiny lcd setup to run PCB with the OSSC, what 17"-20" LCD would choose? CRT it's not an option

A 5:4 IPS LCD if you want best image quality, or a lightboost enabled (assuming it works @60Hz) TN of you want best motion handling.

How well do most modern displays deal with off-spec refresh rates on DVI/HDMI inputs? Will a SNES work on a modern display? a EU console playing US titles? I assume you've tested some displays and have some idea on this.

Typical displays sync fine if the refresh rate is under +-1Hz off the spec, but some may have stutter if they run @59.94Hz internally. From my experience computer monitors are more compatible.

So I've made custom VGA cables for all my RGB consoles. They have composite sync on the H pin. Would that work with the VGA input on this device?

Yes, if composite sync is TTL/CMOS level. However, VGA input is not routed through the LPF chip so it may still be better to use SCART via an adapter.

[BazookaBen]

Yes, if composite sync is TTL/CMOS level. However, VGA input is not routed through the LPF chip so it may still be better to use SCART via an adapter.

Why is the LPF necessary? Does it improve picture quality? I would be using this to play on a PC CRT via an HD Fury for the most part, maybe sometimes a standard LCD TV.

The composite sync level would be whatever the consoles put out. I'd be using a modded SNES Jr., a VA 7 Genesis (I think), and a Saturn.

[marqs]

Yes, if composite sync is TTL/CMOS level. However, VGA input is not routed through the LPF chip so it may still be better to use SCART via an adapter.

Why is the LPF necessary? Does it improve picture quality? I would be using this to play on a PC CRT via an HD Fury for the most part, maybe sometimes a standard LCD TV.

The composite sync level would be whatever the consoles put out. I'd be using a modded SNES Jr., a VA 7 Genesis (I think), and a Saturn.

LPF is good for 2 things: First, if the console's video output is less than ideal and has noise (many old systems), LPF can help in reducing that. Secondly, if the source is sampled with a rate which doesn't match its DAC output rate (e.g. SNES outputs with a rate of 256 active pixels per scanline while the digitizer samples that with 720 samples - typical linedouble situation), there is always some microjitter present. With LPF, transitions from one pixel value to another are not so immediate which mitigates microjitter. SNES and Saturn output TTL level sync as far as I know, and Genesis too unless c-sync is taken from its CXA chip.

[BazookaBen]

Thanks. If I end up buying one I'll probably test it on the VGA input first to see if the jitter is worse.

But generally the jitter is only by a pixel or so and isn't super noticeable, right? So I'm not sure if jitter three times a second is any worse than twice a second or whatever.

[jandrogo]

One silly question, I want to build a tiny lcd setup to run PCB with the OSSC, what 17"-20" LCD would choose? CRT it's not an option

A 5:4 IPS LCD if you want best image quality, or a lightboost enabled (assuming it works @60Hz) TN of you want best motion handling.

Would you recommend 5:4 over 4:3 or 16:9?
Which native resolution for the sharpest image and better quality.
1280x1024?
1600x1200?
1366x768?

[marqs]

But generally the jitter is only by a pixel or so and isn't super noticeable, right? So I'm not sure if jitter three times a second is any worse than twice a second or whatever.

It's not super noticeable unless you look very close.

Would you recommend 5:4 over 4:3 or 16:9?
Which native resolution for the sharpest image and better quality.

At that size range, you probably don't want 16:9 with large black borders on both sides. Most non-widescreen LCD monitors are 5:4, but of course 4:3 is better if you happen to find a quality monitor with that aspect. Native resolution is not that important if you mainly play retro games, instead you should ensure that the monitor has sufficient scaling options & quality.

[Fudoh]

Most non-widescreen LCD monitors are 5:4

actually just 17" and 19" ones were 5:4. 15", 20" and 21" were 4:3 (1024x768 for 15" and 1600x1200 for 20 and 21"). Not sure about the 18" ones, but these were quite rare anyway.

[SNK-NEO-GEO]

Wowwwwww... I love this project.. I can not wait to read reviews and see how the product improves/matures from one revision to the next.. the Next revision clearly needs both VGA and HDMI output. I have a wallet full of money waiting for the VGA and HDMI output version:). Keep up the good work..

[bobrocks95]

Wowwwwww... I love this project.. I can not wait to read reviews and see how the product improves/matures from one revision to the next.. the Next revision clearly needs both VGA and HDMI output. I have a wallet full of money waiting for the VGA and HDMI output version:). Keep up the good work..

DIY-kit has HDMI output (without audio), while the complete unit has DVI-D output (only digital). VGA output would have raised the costs and design time plus majority would use only digital output, which are the reasons why it was left out. HDMI/DVI-D to VGA converters are relatively cheap - there's some discussion on those on previous pages and on other threads.

Unlikely to be added I'd say. More likely (purely conjecture on my part of course) would be a VGA-only version- while both would be nice a majority of owners probably would just use one or the other. Maybe a lot of people requesting it will lead marqs to change his mind, but you never know.

Also, @marqs- "4 different sampling configurations" for the linetripling mode- have all 4 of these been posted as a custom resolution for people to try? I remember one or two earlier in the thread but not 4. Can we get them collected in a single post for testing, or maybe I just missed this already?

[Fudoh]

have all 4 of these been posted as a custom resolution for people to try?

marqs shall correct me if I'm wrong, but the sampling config doesn't affect the output timing.

[Mantrox]

Is somebody else itching for some more video examples?
Can i beg?

[jandrogo]

At that size range, you probably don't want 16:9 with large black borders on both sides. Most non-widescreen LCD monitors are 5:4, but of course 4:3 is better if you happen to find a quality monitor with that aspect. Native resolution is not that important if you mainly play retro games, instead you should ensure that the monitor has sufficient scaling options & quality.

Most non-widescreen LCD monitors are 5:4

actually just 17" and 19" ones were 5:4. 15", 20" and 21" were 4:3 (1024x768 for 15" and 1600x1200 for 20 and 21"). Not sure about the 18" ones, but these were quite rare anyway.

Great, I will go for a second hand Eizo monitor to get nice results

[Hoagtech]

Is somebody else itching for some more video examples?
Can i beg?

I will..

let's see some pixel porn marqs

[Rune]

Something's just hit me that I probably should've thought about a while ago. I was looking to use this with SCART sources and for some reason I just assumed I'd get audio via the HDMI output (which is pretty much the only reason why I was originally favouring a kit with HDMI over DVI-D). Realising I'll need to use the audio passthrough, I'm now trying to figure out how I'm going to combine audio and video.

The way my devices are set up, I use a 5 way HDMI switch, which goes into a HDMI splitter. One outputs into my gaming monitor, and the other output goes into a BlackMagic Intensity Pro card.

So in this case, is my only option to get some kind of "DVI-D + Audio to HDMI" convertor box? Is there no such cable that can do this with out having to have another device/box in the chain?
And if I did have to get a convertor, will this add more input lag?

[Hoagtech]

Something's just hit me that I probably should've thought about a while ago. I was looking to use this with SCART sources and for some reason I just assumed I'd get audio via the HDMI output (which is pretty much the only reason why I was originally favouring a kit with HDMI over DVI-D). Realising I'll need to use the audio passthrough, I'm now trying to figure out how I'm going to combine audio and video.

The way my devices are set up, I use a 5 way HDMI switch, which goes into a HDMI splitter. One outputs into my gaming monitor, and the other output goes into a BlackMagic Intensity Pro card.

So in this case, is my only option to get some kind of "DVI-D + Audio to HDMI" convertor box? Is there no such cable that can do this with out having to have another device/box in the chain?
And if I did have to get a convertor, will this add more input lag?

I just use a scart switch switch box with audio pass through. You find them on eBay 35 bucks.

http://www.ebay.com/itm/Professional-Sc ... xyUSFSKRtq

Some people have problems with these models. I do not. I own 2 of them daisy chained and need to buy another actually.

[blizzz]

Hoagtech, that box won't solve his problem in any way. There is already an audio passthrough on this device.

Rune, yea, a DVI-D + Audio to HDMI converter is most likely the easiest solution, although they are quite expensive. A simple cable won't do the job since the audio must be digitized and interleaved with the video.

Also something to consider in this regard. If you're using a TV with a bit of input delay and you're feeding the audio directly to your speakers, the picture will be behind the audio by a bit. You'll either need a TV that can accept analog audio for an HDMI input or an audio receiver that can delay the audio.

[Mantrox]

Something's just hit me that I probably should've thought about a while ago. I was looking to use this with SCART sources and for some reason I just assumed I'd get audio via the HDMI output (which is pretty much the only reason why I was originally favouring a kit with HDMI over DVI-D). Realising I'll need to use the audio passthrough, I'm now trying to figure out how I'm going to combine audio and video.

The way my devices are set up, I use a 5 way HDMI switch, which goes into a HDMI splitter. One outputs into my gaming monitor, and the other output goes into a BlackMagic Intensity Pro card.

So in this case, is my only option to get some kind of "DVI-D + Audio to HDMI" convertor box? Is there no such cable that can do this with out having to have another device/box in the chain?
And if I did have to get a convertor, will this add more input lag?

In my case im thinking of using the DVDO edge to fulfill that duty.
[Saturn]
-- RGB scart --
[OSSC]
-- HDMI + (3.5mmjack - 2 RCA)--
[DVDO Edge]
-- HDMI --
[Dell 27"]

Im not sure, but this setup should be a good option if i feed 480P to the DVDO.

Probably not an option in your case, as it's not as cheap or as available as other solutions.

Edit: Oh i remembered that i ordered a complete kit so instead of plain hdmi it will be a DVI-HDMI cable.

[kditd]

does somebody know if this will work with a LG PA70G projector in 720p?

[marqs]

have all 4 of these been posted as a custom resolution for people to try?

marqs shall correct me if I'm wrong, but the sampling config doesn't affect the output timing.

Yes, the resulting modeline is almost same with all linetriple modes. The total number of pixels per scanline only changes a little - e.g. 320x240 optimized mode uses 426*4=1704 pixels and 256x240 optimized mode uses 341*5=1705 pixels.

Is somebody else itching for some more video examples?
Can i beg?

I will..

let's see some pixel porn marqs

Okay, I should add a few short clips showcasing those pixel-perfect linetriple modes .

[BuckoA51]

In my case im thinking of using the DVDO edge to fulfill that duty.

DVDO Edge will work, but will add between 6 and 30ms of lag. I'm sure I've seen DVI+Audio to HDMI integrators for reasonable prices (under £50). Google and eBay around. They don't add lag as far as I am aware since they don't have frame buffers.

[Mantrox]

In my case im thinking of using the DVDO edge to fulfill that duty.

DVDO Edge will work, but will add between 6 and 30ms of lag. I'm sure I've seen DVI+Audio to HDMI integrators for reasonable prices (under £50). Google and eBay around. They don't add lag as far as I am aware since they don't have frame buffers.

Ill try different configurations and report back once i get the OSSC.
Otherwise ill hook up the sound directly to my amp, and see if the delay is bothersome enough.

[rtw]

In my case im thinking of using the DVDO edge to fulfill that duty.

DVDO Edge will work, but will add between 6 and 30ms of lag. I'm sure I've seen DVI+Audio to HDMI integrators for reasonable prices (under £50). Google and eBay around. They don't add lag as far as I am aware since they don't have frame buffers.

Some lazy googling...

http://www.ebay.com/itm/StarTech-com-DV ... 1314206654

[bobrocks95]

Here's a cheaper one:
http://www.monoprice.com/product?pg_no2 ... 1&format=4

[badwhite40]

Late To the party, but I've order one today.
Cheers!

Little worried about how connect this to the vga vewlix D display.

[Mantrox]

Not sure but a HD fury should do the trick for you.
I remember there was some shenanigans about the sync polarity with it (depending on the version as well), so you should read up on it a bit before committing.

[marqs]

Okay, I should add a few short clips showcasing those pixel-perfect linetriple modes .

Here is one. That's taken by setting H_SAMPLERATE to 427 - somebody who knows Saturn hw could verify if that exactly matches Saturn output.

A few days ago I finally had a chance to personally test some arcade boards (Armed Police Batrider, Brave Blade, Gaplus, Raiden, Raiden 2 DX, R-Type Leo, Super Mario Bros, Super Space Invaders, Truxton, Viper Phase 1). As expected, they were a lot trickier than consoles, with wildly different refresh rates and line counts. Initially many of those failed to sync reliably with OSSC. After some debugging, the problem was traced to TVP7002 chip which randomly reported no sync even when everything was working. A small workaround (there's now quite a few for TVP7002 bugs) was added which pretty much fixed this issue. In the end, only Super Space Invaders out of the 10 boards couldn't sync - I'll have to examine its signal to find out if there's something strange.

[Xyga]

Wow. So...clean !