New feature: YPbPr/RGsB output

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Sorgelig
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New feature: YPbPr/RGsB output

Postby Sorgelig » Thu Jan 12, 2017 3:17 pm

Info about cable: https://github.com/mist-devel/mist-boar ... PbPr_Cable

As probably everybody know, VGA isn't native TV input and not all TV have this input. Another problem of VGA output is vertical frequency minimum of 56Hz(60Hz for most monitors). So scandoubled or interlaced video produced by MiST for PAL cores are out of VGA specs. So only few monitors and TVs can accept such VGA signal.
SCART cable can help in some cases, but today it's not a common connector already. Also most countries outside of Europe don't have TV with SCART. SCART limits video to interlaced video only.

So, i introduce a new and more suitable solution - YPBPr connection. YPbPr cable is most common among analog connections today. And it's a world standard unlike SCART. YPbPr supports both interlace SDTV(576i50, 480i60) and progressive EDTV(576p50, 480p60) video which means you can use scandoubled video through this connection. More interesting is that you can output both interlace and progressive videos from different cores through single cable without re-connection. And since YPbPr supports HDTV, cores have potential to output 720p, 1080i and 1080p. All these resolutions are in standard unlike that semi-VGA signal for selected monitors.

I've updated Firmware and all my cores to support new video output. NES and C64 cores updated in binary repository. Minimig_AGA with YPbPr support is here: https://github.com/mist-devel/mist-bina ... 170113.zip.
I hope Minimig original repository will include YPbPr soon.

Anyone is welcome to test new video mode.
Some TV/Scalers can be picky to precise frame format. I found some scalers don't like 320 lines scandoubled video (640 total lines instead of 625 by standard), while others work fine.
Last edited by Sorgelig on Fri Jan 13, 2017 10:39 am, edited 3 times in total.

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Thu Jan 12, 2017 3:20 pm

The same cable can be used as RGsB (Sync-On-Green) for all cores. It doesn't require ypbpr (nor core modification) setting in ini file, but it requires TV/Monitor supporting RGsB signal.

Update: Using just Y connector you can have monochrome composite signal.
Last edited by Sorgelig on Fri Jan 13, 2017 8:05 am, edited 1 time in total.

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Re: New feature: YPbPr/RGsB output

Postby bernouilli » Thu Jan 12, 2017 4:28 pm

Sounds good.
But how do you choose between RGBs (scandouble disabled) and YPbPr?

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Re: New feature: YPbPr/RGsB output

Postby Cogweasel » Thu Jan 12, 2017 5:38 pm

This could be excellent news for me! Been tempted to buy a MiST for a while, but the lack of an easy way to record video from it has put me off a bit. This might make things easier. I think YPBPr should be capturable with my Avermedia LGP... possibly at least. Any plans of selling the cables?

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Re: New feature: YPbPr/RGsB output

Postby foft » Thu Jan 12, 2017 9:34 pm

Great idea!

How flexible have you found your TV to be with component? I mean in terms of exact standard timing CEA modes?

With my TVs HDMI port I find the timing needs to be really exact to the standard. Which is ok, but requires minor over/underlocking of the core to 50Hz/60Hz exactly.

Other options possible over the mist vga port are composite and svideo. Are any cores using these?

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Re: New feature: YPbPr/RGsB output

Postby sadosp » Thu Jan 12, 2017 11:05 pm

Cogweasel wrote:Any plans of selling the cables?


Why not ask in your local electronic hardware or HI-FI audio/video shop, for VGA 15-pin male to component 3xRCA male adapter cable?
Or from eBay?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.X+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA.TRS0&_nkw=+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA&_sacat=0

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Thu Jan 12, 2017 11:13 pm

sadosp wrote:Why not ask in your local electronic hardware or HI-FI audio/video shop, for VGA 15-pin male to component 3xRCA male adapter cable?
Or from eBay?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.X+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA.TRS0&_nkw=+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA&_sacat=0

They wont work! These cables are just bare wire connections while YPbPr cable for MiST requires small circuit inside.
I think you need to ask Lotharek for such cable. I'm unable to make a production.
Actually it's easy to make it by yourself if you can solder ;)

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Thu Jan 12, 2017 11:16 pm

foft wrote:Great idea!

How flexible have you found your TV to be with component? I mean in terms of exact standard timing CEA modes?

With my TVs HDMI port I find the timing needs to be really exact to the standard. Which is ok, but requires minor over/underlocking of the core to 50Hz/60Hz exactly.

Other options possible over the mist vga port are composite and svideo. Are any cores using these?

My TV is 60hz only. I'm testing different scalers. Some scalers are more tolerable, some are less. This question still needs more tome to find out the answer. I expect signal compatibility not worse than with SCART. At least for interlaced modes.

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Re: New feature: YPbPr/RGsB output

Postby leech » Thu Jan 12, 2017 11:25 pm

I just ordered one of these; https://www.amazon.com/Monoprice-Compon ... nent+cable

I'll report back after I get it to let everyone know how it works. Now the question is... where's the upgraded Atari ST core for it? :)

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Re: New feature: YPbPr/RGsB output

Postby leech » Thu Jan 12, 2017 11:26 pm

Sorgelig wrote:
sadosp wrote:Why not ask in your local electronic hardware or HI-FI audio/video shop, for VGA 15-pin male to component 3xRCA male adapter cable?
Or from eBay?

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR0.TRC0.H0.X+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA.TRS0&_nkw=+Component+RGB+YUV+3+RCA+male+To+D-sub+15-Pin+VGA&_sacat=0

They wont work! These cables are just bare wire connections while YPbPr cable for MiST requires small circuit inside.
I think you need to ask Lotharek for such cable. I'm unable to make a production.
Actually it's easy to make it by yourself if you can solder ;)


Oh crap, what sort of small circuit does it require? So it still requires a VGA to component conversion?

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Re: New feature: YPbPr/RGsB output

Postby Newsdee » Fri Jan 13, 2017 3:42 am

This is the adapter (from OP's link):
Image

I would imagine this only works for the MIST, it is not a general VGA to Component converter. Could be a good idea to mount it to a little PCB that can also split the stereo jack into two RCA, that way it can fully connect to TVs with regular cables.

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Fri Jan 13, 2017 6:20 am

I'm amazing how people ignore my link in the first post. It's on the first line! How come??

Newsdee wrote:I would imagine this only works for the MIST, it is not a general VGA to Component converter. Could be a good idea to mount it to a little PCB that can also split the stereo jack into two RCA, that way it can fully connect to TVs with regular cables.

I've build this circuit just inside VGA connector case without PCB. Just connected the components directly.

YPbPr cable doesn't include Audio. Physically Audio and Video inputs can be far from each other and it's not convenient to combine audio and video together like it's done for SCART where all signals are in single connector. 3,5mm to RCA cable is pretty common and can be purchased everywhere.

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Fri Jan 13, 2017 6:22 am

As for cable - it can be used for any VGA output device to create RGsB connection. The only requirement: HSync and Vsync should use negative pulses.

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Re: New feature: YPbPr/RGsB output

Postby Newsdee » Fri Jan 13, 2017 6:49 am

Yes I know its a simple circuit, but I had a PCB in mind because it's easier to mount/solder one, and it would allow making a neat backpanel to connect regular cables (instead of having a special VGA to YPbPr cable). It would have to connect both to the VGA and the 3.5mm audio plug, of course.

One could also take the idea further and make a docking station with VGA pass-through and SCART thrown in as well :D

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Fri Jan 13, 2017 7:53 am

Here is how i've made it:
IMG_20170113_1508_0185.jpg

IMG_20170113_1509_0186.jpg

IMG_20170113_1511_0187.jpg
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Re: New feature: YPbPr/RGsB output

Postby DrOG » Fri Jan 13, 2017 7:04 pm

Just ordered the necessary components, next week I will solder my own vga2ypbpr cable...

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Fri Jan 13, 2017 11:43 pm

I think any NPN transistor should work. Direct SMD-type analog is BC847.

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Re: New feature: YPbPr/RGsB output

Postby DrOG » Sat Jan 14, 2017 7:02 am

I ordered a Philips BC547C NPN 45V 0.1A TO92 transistor, the capacitor is 100uF 16V 105°C Low ESR 5x11mm -TEAPO electrolyte type, the resistors are 680 Ohm 0.125W carbon and 1 KOhm 0.4W metal type, hope they will do the job.

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Re: New feature: YPbPr/RGsB output

Postby bernouilli » Sat Jan 14, 2017 11:59 am

I managed to make it work on my PVM monitor (c64 core and zxspectrum), I still use my old cable VGA->RGBHV but I must use external sync ont the pvm.
I ordered stuff to build the right cable to test it on my TV.

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Re: New feature: YPbPr/RGsB output

Postby bernouilli » Sat Jan 14, 2017 4:43 pm

I just realize that the ypbpr output shouldn't work with my cable and yet it works.
I use a vga to rgbvh cable connected to my Sony pvm and I use 15khz mode (scan doubler disabled). The V synchro cable isn't connected and the H synchro cable drives the sync signal which is a mix of the vsync and hsync (see scart cable for mist).
The schematic of the ypbpr cable shows that the two sync signals must be mixed together using the transistor and merged with the Green signal.
Then how come I get a stable picture (on c64 core, spectrum core and menu) with only the Hsync cable (pin 13 of CFA connector)?

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Sat Jan 14, 2017 4:50 pm

Because your monitor supports RGBS video - same as SCART.

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Re: New feature: YPbPr/RGsB output

Postby bernouilli » Sat Jan 14, 2017 7:03 pm

Yes my monitor support RGBS, but what I mean is that if I use 15khz then the two sync signal are mixed even though ypbpr is on.
I guess that the ypbpr isn't compatible with the scandoubler disabled. You wrote that ypbpr support 576i50 and 480i60 modes which are the lowest modes. And these modes cannot be achieved on c64 without using scandoubler.

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Re: New feature: YPbPr/RGsB output

Postby Sorgelig » Sun Jan 15, 2017 3:16 am

scandoubler disabled = 576i50/480i60 (15KHz)
scandoubler enabled = 576p50/480p60 (31KHz)
both modes supported in YPbPr mode and composite sync (pin 13) is provided if YPbPr enabled.

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Re: New feature: YPbPr/RGsB output

Postby bernouilli » Sun Jan 15, 2017 9:10 am

Thanks, now it's perfectly clear.

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Re: New feature: YPbPr/RGsB output

Postby Cogweasel » Tue Jan 17, 2017 7:56 pm

Sorgelig wrote:Actually it's easy to make it by yourself if you can solder ;)

I can solder... somewhat decently :). But I am a bit lazy and my soldering station is just barely working at the moment. But things may change of course :D


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