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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 11:11 am 



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I uploaded some videos to compare GBI High Fidelity 480x360 with RGB SCART and Component. I only have a cheap unshielded RGB cable to use with my PAL Gamecube so there is massive interference from the chroma carrier visible. Its also much blurrier than component cables.

With Analog sync Vth 101mV, Analog sync LPF 10Mhz and Video LPF 33Mhz there was only a tiny bit of jitter in the middle of the screen.

RGB cable:
https://youtu.be/E8Nrs6cHBpg

Component cable:
https://youtu.be/hLApXLFYgtI

Harrumph wrote:
Currently, ossc can only linedouble this, but paulb has made a custom fw to achieve x3 (1080p), and also a custom optimized mode. He didn’t release this yet though. I assume since ossc is so full now, he had to take some other features out.


Well I just use the non-audio firmware and that still has plenty of space left. Indeed there would have to be something removed from the audio firmware to make it fit.

BTW The Hz on the main OSSC display is not always accurate. If you press Info on the remote and divide 27000000 with the number on the bottom right you get an accurate value.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 11:38 am 


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Ok that is MUCH less jitter than what I see, like orders of magnitude. So maybe there is something up with my GCN then. :(
I'm using cable from retrogamingcables.co.uk, not the packapunch version but it should be ok shielded still.

And I assume then what you see on your OSSC is an exact 60Hz?


I had recorded a video previously, I uploaded it just now. Pause the video to really see the jitter pattern.
https://youtu.be/6UzYpMiBPdw

Note that is with regular gbi, but I did test with the new gbihf also and the results are the same.

paulb_nl wrote:
BTW The Hz on the main OSSC display is not always accurate. If you press Info on the remote and divide 27000000 with the number on the bottom right you get an accurate value.


Thanks for the tip, I'll check that next time I have opportunity. Actually, I seem to remember Marqs has already improved once how Vfreq was calculated even for the main screen?


Edit: btw just for fun, here is what the GBI 960x360 looks like through my rgb cable (with ossc switched to component input)
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 4:27 pm 


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Harrumph wrote:
To perhaps get a bit more data, I’ll post my ossc settings for the 360p gbi output so people can easily test. Note that this concerns output via rgb-scart on regular PAL GC, we already know it works with component cable.

Gbi or gbihf needs to have following parameters to output 480x360p60:
--format=hd60
--scan-mode=non-interlace,no-clock2x,no-size2x

Edit: also use --scaler=nearest
Otherwise there is some blending vertically.

One needs to edit the dcp, cli or dol file accordingly.

OSSC sees this as 384p. It has 375 lines and (according to my ossc) 59.95hz. I had to increase Analog sync Vth to 169 to not get occasional sync drops.


My OSSC sees this as 261p, so I assume my gbihf.dol/gbi.dol did not use the settings in the gbihf.cli/gbi.cli file?


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 4:52 pm 


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It's not GBI that uses the file, but Swiss. You need to append the file if you're not using Swiss.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 4:53 pm 


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EDIT: ah right Extrems has the answer, I had forgotten that .cli was dependent on using Swiss. :) Like he writes, append to the end of the .dol files directly then (ie open dol with text editor and paste in the lines at the very end). Tbh, if you plan on testing out a lot of stuff, I would suggest booting via swiss, but using the dcp files instead of cli, so the options are selectable each time you start.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 5:21 pm 


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I'm actually using the latest swiss, but it seems hit & miss for me. Worked with the normal GBI now, but I cannot get it to full screen with the stretch ability of my TV (Sony Bravia).
Sometimes it also won't display anything. Line2x and stretching to fullscreen with aspect ratio seems to do fine (240p), but albeit a bit blurry. :)


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 7:07 pm 


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So you didn’t get 360p to work? I should add for regular gbi you should use zoom factor of 4 if using 360p. You can either set that via command ––zoom=4 or just increase it via the OSD (hit right shoulder button to increase).

Sony TVs are often picky with input signals, but linex2 360p from GBI is almost identical to standard 720p, if setting it to 16:9, so I would be surprised if it didnt work actually.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 7:21 pm 


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https://www.gc-forever.com/wiki/index.php?title=Game_Boy_Interface/Standard_Edition#Open_Source_Scan_Converter
https://www.gc-forever.com/wiki/index.php?title=Game_Boy_Interface/High-Fidelity_Edition#Open_Source_Scan_Converter

Those are the exact settings you need.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 06, 2018 9:17 pm 



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Harrumph wrote:
Ok that is MUCH less jitter than what I see, like orders of magnitude. So maybe there is something up with my GCN then. :(
I'm using cable from retrogamingcables.co.uk, not the packapunch version but it should be ok shielded still.


Yea your jitter is extreme. Does your cable have a sync stripper inside? Have you tried tweaking Sync LPF?

Quote:
And I assume then what you see on your OSSC is an exact 60Hz?


It varies. Mostly its 60 but sometimes it can be 59.95 and 60.15 depending on Analog sync Vth and Sync LPF settings. It can change if you switch between inputs.

Quote:
Thanks for the tip, I'll check that next time I have opportunity. Actually, I seem to remember Marqs has already improved once how Vfreq was calculated even for the main screen?


The main screen calculation still relies on numbers provided by the digitizer which sometimes are not correct.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Sun Jun 10, 2018 4:45 pm 


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Has anyone measured input lag on the 2017 LG OLED TVs with 480i passthrough? :)


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Mon Jun 11, 2018 4:06 pm 


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Does anyone know if it is outside of the OSSC's hardware capabilities to linedouble 720p to 1440p? I know it's not supported in firmware, but it would be awesome to be able to line double PS3 and Xbox 360 games for displays that can accept 1440p. The Samsung in my game room seems to handle downsampling 1440p better than upsampling 720p for example.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Mon Jun 11, 2018 5:03 pm 



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Arthrimus wrote:
Does anyone know if it is outside of the OSSC's hardware capabilities to linedouble 720p to 1440p? I know it's not supported in firmware, but it would be awesome to be able to line double PS3 and Xbox 360 games for displays that can accept 1440p. The Samsung in my game room seems to handle downsampling 1440p better than upsampling 720p for example.

I believe the OSSC, as it exists in its current form, isn't programmed with any capability for 720p or greater besides passthrough; and, although the HDMI transmitter chip (IT6613) is apparently capable of 2560x1440@75Hz, I'm not sure that the FPGA has the overhead needed for that mode. We may see Line2x support for 720p in future if the future soft-CPU replacement runs lean/fast enough (I'm assuming the current software does not), but I would not expect it without marqs explicitly stating it's doable.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Mon Jun 11, 2018 7:34 pm 



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Konsolkongen wrote:
Has anyone measured input lag on the 2017 LG OLED TVs with 480i passthrough? :)


It would be virtually the same as without the OSSC as the OSSC adds virtually no lag in any mode.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Mon Jun 11, 2018 7:45 pm 


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Quote:
It would be virtually the same as without the OSSC as the OSSC adds virtually no lag in any mode.

but the TV adds more lag for interlaced sources than it does for progressive ones - hence his question.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Mon Jun 11, 2018 9:41 pm 


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Going thru some backlog:
nmalinoski wrote:
orange808 wrote:
FWIW, aspect ratio, overscan, and underscan shouldn't require a full frame buffer. Most of us would just continue to use our DVDOs.

Okay, then deinterlacing, adjustable zoom, framerate normalization (should help with display compatibility), and maybe PAL<->NTSC format conversion (for giggles).

I find it hard to believe that "most of us" have DVDOs or the budget for one--I know there are a number of members that have them, but I don't--and it doesn't help that all of the applicable DVDO scalers are discontinued; I imagine an OSSC with this kind of functionality would be better supported, more available, and still cheaper than a Framemeister or a used DVDO.
It'd hard to make a true game-oriented next-gen scanconverter/scaler cheaper than FM/DVDO without cutting corners. Even if you found an ASIC that did all those things at decent price and availability for small-scale projects, using one would trade off most of the flexibility/configurability and potentially had limitations regarding to features and performance (e.g. latency). Doing all processing with FPGA would be the way to go, but for that you'd preferably use a high-end one, especially if you wanted to consider 4K support. A glance into e.g. Arria 10 or Cyclone 10 GX prices shows that they don't come cheap unless you have contacts to right dealers and commit to buy them in hundreds or thousands. Then you'd need to take into account costs from increased PCB complexity, design software and IP (which generally is free only for low-end FPGAs), other components etc. I don't want to sound too pessimistic or say it's something that couldn't happen in future, but one shouldn't underestimate costs of making an uncompromized device for relatively small audience.

Arthrimus wrote:
I'm building a batch of OSSC boards and I've run into a snag with parts sourcing. Does anyone know of a drop in replacement for U10? According to Mouser the S25FL216K is an end of life product, and the only place I can find it is on Aliexpress. If there is a current production part available I'd love to know about it.
Is S25FL216K still lingering in some instructions? I recall replacing it with IS25LP016D-JBLE on the official BOM at least.

FBX wrote:
What we'd need are independent horizontal scaling from the vertical line scaling. That way, you could say optimally time the 704 (would still require a range increase on the OSSC's firmware) at 2x scale, and then set the vertical to 4x scale, giving a 1408x960 image, which is much more reasonable.

Edit: And I should specify that you can optimally time 704 when the vertical is at 480, but not 240.
Making horizontal and vertical timings fully independent is not viable with current implementation which is at the mercy of limited PLL input frequency ranges. However, that kind of horizontal 2x/vertical 4x for 704x240 is well within valid range so it'd just need a suitable preset.

nmalinoski wrote:
Arthrimus wrote:
Does anyone know if it is outside of the OSSC's hardware capabilities to linedouble 720p to 1440p? I know it's not supported in firmware, but it would be awesome to be able to line double PS3 and Xbox 360 games for displays that can accept 1440p. The Samsung in my game room seems to handle downsampling 1440p better than upsampling 720p for example.

I believe the OSSC, as it exists in its current form, isn't programmed with any capability for 720p or greater besides passthrough; and, although the HDMI transmitter chip (IT6613) is apparently capable of 2560x1440@75Hz, I'm not sure that the FPGA has the overhead needed for that mode. We may see Line2x support for 720p in future if the future soft-CPU replacement runs lean/fast enough (I'm assuming the current software does not), but I would not expect it without marqs explicitly stating it's doable.
Any source to back up IT6613's support for 2560x1440@75Hz? The chip would need to run at almost double of the max. 162MHz input pixel clock specified in datasheet. With pixel repetition you could partially get around that, but output TMDS clock would still far exceed the highest mentioned frequency.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 12:23 am 


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marqs wrote:
However, that kind of horizontal 2x/vertical 4x for 704x240 is well within valid range so it'd just need a suitable preset.


So how would you do it for optimal timing? Obviously you would use line4x for the vertical, but how would you optimally time the horizontal such that it's still nearest neighbor scaled, only at 2x instead of 4x?
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 1:47 am 



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marqs wrote:
nmalinoski wrote:
I believe the OSSC, as it exists in its current form, isn't programmed with any capability for 720p or greater besides passthrough; and, although the HDMI transmitter chip (IT6613) is apparently capable of 2560x1440@75Hz, I'm not sure that the FPGA has the overhead needed for that mode. We may see Line2x support for 720p in future if the future soft-CPU replacement runs lean/fast enough (I'm assuming the current software does not), but I would not expect it without marqs explicitly stating it's doable.
Any source to back up IT6613's support for 2560x1440@75Hz? The chip would need to run at almost double of the max. 162MHz input pixel clock specified in datasheet. With pixel repetition you could partially get around that, but output TMDS clock would still far exceed the highest mentioned frequency.

Thanks for calling me on that. It was an assumption based on the HDMI spec they advertise for that chip (1.3, 1.4a) and the maximum capability that spec is supposed to have. After skimming the data sheet, it looks like the maximum resolution they specify in their Input Pixel Clock Frequency table is UXGA (1600x1200) with 24bit color.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 2:14 am 


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marqs wrote:
Arthrimus wrote:
I'm building a batch of OSSC boards and I've run into a snag with parts sourcing. Does anyone know of a drop in replacement for U10? According to Mouser the S25FL216K is an end of life product, and the only place I can find it is on Aliexpress. If there is a current production part available I'd love to know about it.
Is S25FL216K still lingering in some instructions? I recall replacing it with IS25LP016D-JBLE on the official BOM at least.

I must be working from an outdated BOM. I believe I got it from the instruction downloads from videogameperfection, I used one of their DIY kits to build my first OSSC, this time around I'm building from scratch.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 9:53 am 



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FBX wrote:
So how would you do it for optimal timing? Obviously you would use line4x for the vertical, but how would you optimally time the horizontal such that it's still nearest neighbor scaled, only at 2x instead of 4x?


It requires a firmware update with something like 640x240 optimized mode. Though that mode is probably only usable in line4x. Line3x would only output 1280x720 so no 4:3 and its not possible to use 640x240 in line5x mode.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 10:49 am 


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paulb_nl wrote:
FBX wrote:
So how would you do it for optimal timing? Obviously you would use line4x for the vertical, but how would you optimally time the horizontal such that it's still nearest neighbor scaled, only at 2x instead of 4x?


It requires a firmware update with something like 640x240 optimized mode.


Okay, I was under the impression from Marqs's reply that we can do this right now in the OSSC without an update.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 11:39 am 



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I don't have the budget for a Toro/Akura box for my dreamcast at the moment.

If I use this:
Image

I can play the games that support VGA on the dreamcast, right?

The games that doesn't support it I believe I have two options?
1. I have a USB GD Rom so I could "hack" VGA support on those games?

2. I believe there is a pin that you need to short that enables VGA and "unshort" it and you get RGB 15khz.

Is this a bad idea, is there something I'm not paying attention to this setup?
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 1:00 pm 



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fandangos wrote:
I don't have the budget for a Toro/Akura box for my dreamcast at the moment.

If I use this:
Spoiler: show
Image


I can play the games that support VGA on the dreamcast, right?

The games that doesn't support it I believe I have two options?
1. I have a USB GD Rom so I could "hack" VGA support on those games?

2. I believe there is a pin that you need to short that enables VGA and "unshort" it and you get RGB 15khz.

Is this a bad idea, is there something I'm not paying attention to this setup?

Personally, I would save up for a Toro (especially if the rest of your gaming setup is set up for RGBS), or even wait for the DC HDMI board (which should give you options, where the Akura gives you none); but, if you already have this cable, you will indeed be able to run your games in VGA mode, though you may get interference from other cabling, as straight VGA cables like that generally aren't shielded (because they're cheap). You are correct for both options, though I imagine it will be a pain, and quite messy, to modify that cable to add in a mode switch, and who knows how much longer these GD-ROM drives will last.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 1:52 pm 



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Fudoh wrote:
Quote:
It would be virtually the same as without the OSSC as the OSSC adds virtually no lag in any mode.

but the TV adds more lag for interlaced sources than it does for progressive ones - hence his question.


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.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 4:58 pm 


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thebigcheese wrote:
Fudoh wrote:
Quote:
It would be virtually the same as without the OSSC as the OSSC adds virtually no lag in any mode.

but the TV adds more lag for interlaced sources than it does for progressive ones - hence his question.


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.


I would be very interested in the link for the television deinterlacing database.
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 5:11 pm 



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nmalinoski wrote:
Personally, I would save up for a Toro (especially if the rest of your gaming setup is set up for RGBS), or even wait for the DC HDMI board (which should give you options, where the Akura gives you none); but, if you already have this cable, you will indeed be able to run your games in VGA mode, though you may get interference from other cabling, as straight VGA cables like that generally aren't shielded (because they're cheap). You are correct for both options, though I imagine it will be a pain, and quite messy, to modify that cable to add in a mode switch, and who knows how much longer these GD-ROM drives will last.


I removed the GD-Rom and replaced with Mnemo's USB GD Rom. All my games are in a 1TB external hard drives.

A HDMI solution for the DC would be great but I remember so many years ago reading all the development on this in AssemblerGames and Ozone working on this and not sure if anything ever surfaced or if it's vaporware?

Is there someone working on it ?

Also, I've found an easy mod to add internal VGA port and a switch from the DC so I could use regular VGA-VGA cables.
http://www.mmmonkey.co.uk/dreamcast-internal-vga-mod/

I guess with this switch, you can boot a game at RGB and just toggle it for VGA and bypass the game video mode lock.
I just fear for the OSSC.
If I output RGB 15khz into the OSSC for a moment through the VGA port can I damage the OSSC?
Or can this work for a moment?
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 5:20 pm 


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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 :)


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 5:40 pm 



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fandangos wrote:
A HDMI solution for the DC would be great but I remember so many years ago reading all the development on this in AssemblerGames and Ozone working on this and not sure if anything ever surfaced or if it's vaporware?

Is there someone working on it ?
Also, I've found an easy mod to add internal VGA port and a switch from the DC so I could use regular VGA-VGA cables.
http://www.mmmonkey.co.uk/dreamcast-internal-vga-mod/

There is activity in the DreamcastHDMI github by chriz2600 thread as recent as March of this year.

fandangos wrote:
I guess with this switch, you can boot a game at RGB and just toggle it for VGA and bypass the game video mode lock.
I just fear for the OSSC.
If I output RGB 15khz into the OSSC for a moment through the VGA port can I damage the OSSC?
Or can this work for a moment?

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.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Tue Jun 12, 2018 10:51 pm 


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paulb_nl wrote:
FBX wrote:
So how would you do it for optimal timing? Obviously you would use line4x for the vertical, but how would you optimally time the horizontal such that it's still nearest neighbor scaled, only at 2x instead of 4x?


It requires a firmware update with something like 640x240 optimized mode. Though that mode is probably only usable in line4x. Line3x would only output 1280x720 so no 4:3 and its not possible to use 640x240 in line5x mode.
Yes, I was referring a new preset in firmware, e.g. "512x240 optimal" which would be horizontally multiplied by 2 in line3x and 4x modes and by 3 in line5x.


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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 13, 2018 8:10 am 


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Joined: 18 Feb 2015
Posts: 1994
Location: DFW area, Texas
marqs wrote:
Yes, I was referring a new preset in firmware, e.g. "512x240 optimal" which would be horizontally multiplied by 2 in line3x and 4x modes and by 3 in line5x.


Yes, PLEASE!
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 Post subject: Re: OSSC (DIY video digitizer & scandoubler)
PostPosted: Wed Jun 13, 2018 12:46 pm 


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Joined: 25 Dec 2013
Posts: 516
Location: Indiana
nmalinoski wrote:
fandangos wrote:
A HDMI solution for the DC would be great but I remember so many years ago reading all the development on this in AssemblerGames and Ozone working on this and not sure if anything ever surfaced or if it's vaporware?

Is there someone working on it ?
Also, I've found an easy mod to add internal VGA port and a switch from the DC so I could use regular VGA-VGA cables.
http://www.mmmonkey.co.uk/dreamcast-internal-vga-mod/

There is activity in the DreamcastHDMI github by chriz2600 thread as recent as March of this year.


Christof and I are actively working on it still. Just no major news. We are currently trying to figure out some interference issues.


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