tripletopper
Posts: 12
Joined: Sun Jun 09, 2019 1:02 am

Pi baker's help wanted : 2 videos to sync

Sun Jul 25, 2021 1:54 am

It seems like everyone is suggesting I buy a new computer just to sync up two videos that only need have to run live.

Based on what I know Raspberry Pi is a micro computer that could do lots simpler things that a regular size computer but do them for cheaper and can have specialty programs put in and out,

I am like really close to having a red cyan Virtual Boy play on a VGA TV. When I only hook up one vertical sync and one horizontal sync between the two images, whichever one is plugged into the vertical sink has a steady picture for example the left eye has black and red Virtual Boy, and the horizontal sync whether it's plugged into the same input as the vertical sink or the opposite, gets a picture of the black and cyan right eye, but it's slowly crawls to the left. And it constantly crawls to the left at a constant rate.

I don't know how a video syncher works, but it should be able to take two BNC sync signals slightly apart from each other and outputs a new sync signal with the red green and blue synced with the new sink signal.

I know you could add things like BNC connectors as well as HDMI VGA and USB connectors. The rest that it needs is programming a simple program that all just take whatever comes in these two very slightly off sync pictures and sync them up.

I know that for everything except like guns a one millisecond ping time is considered great for conversions between various video formats. It does not have to be accurate to sub microsecond levels where a light gun would work since none of the games I'm playing our light gun games since Virtual Boy has no light gun games, but I do not want a lag in control either.

I was wondering if I could "hire a baker", if that's the correct term, to bake a pie that sinks up to slightly asynchronous VGA signals takes the red of the left takes the cyan of the right and combines them into an anaglyph image with a single picture sink for all three color points.

I'll be willing to hire a baker to build a pie both mechanically and codewise and have it shipped to me.

drgeoff
Posts: 12192
Joined: Wed Jan 25, 2012 6:39 pm

Re: Pi baker's help wanted : 2 videos to sync

Sun Jul 25, 2021 5:17 am

A RPi is far from being the ideal way to tackle your wish. No input for any conventional standard video, no VGA output. Go find out how frame synchronisers work.

Might be more fruitful to investigate how to sync the generation of the two videos.
Quis custodiet ipsos custodes?

tripletopper
Posts: 12
Joined: Sun Jun 09, 2019 1:02 am

Re: Pi baker's help wanted : 2 videos to sync

Mon Jul 26, 2021 6:40 pm

I'm posting on the web in order to find answer, because I don't see the exact answer online. I admit, everything is not easily searchable to everyone.

Would this work:
1. Split each VGA signal into RGBHV with each end being a BNC
2. Route input R1 into Output R. And input G2 and B2 into Output G and B

Not this issue is tricky. I have 2 sync inputs each and need one sync output each.

Would I need a 2 sync input synchronizer (one for V and one for H) to have a VGA signal that will work for my VGA monitor?

Most people say use a Computer. Which made me think of Pi.

Are syncs signal send by the video chip to the TV or is it the reverse, or is it 2 way?

So look at old TV equipment. I've seen Single channel syncher with one BNC in and One BNC out.

If I can't find a 4 in 2 out BNC syncher at a reasonable price on eBay, is it easy to make one?

tripletopper
Posts: 12
Joined: Sun Jun 09, 2019 1:02 am

Re: Pi baker's help wanted : 2 videos to sync

Mon Jul 26, 2021 6:47 pm

I'm posting on the web in order to find answer, because I don't see the exact answer online. I admit, everything is not easily searchable to everyone.

Would this work:
1. Split each VGA signal into RGBHV with each end being a BNC
2. Route input R1 into Output R. And input G2 and B2 into Output G and B

Not this issue is tricky. I have 2 sync inputs each and need one sync output each.

Would I need a 2 sync input synchronizer (one for V and one for H) to have a VGA signal that will work for my VGA monitor?

Most people say use a Computer. Which made me think of Pi.

Are syncs signal send by the video chip to the TV or is it the reverse, or is it 2 way?

So look at old TV equipment. I've seen Single channel syncher with one BNC in and One BNC out.

If I can't find a 4 in 2 out BNC syncher at a reasonable price on eBay, is it easy to make one?

tripletopper
Posts: 12
Joined: Sun Jun 09, 2019 1:02 am

Re: Pi baker's help wanted : 2 videos to sync

Mon Jul 26, 2021 7:57 pm

I got VGA to HDMI adapters, and HDMI to USB adapters, and HDMi output is acceptable. I can input 2 HDMI pictures captured separately. Also once the Red of the Left eye and the Cyan of the Right eye is captured and mixed, one HDMI output is perfectly acceptable.

All I need is RGB additive combination of pictures, and spit the result out as an HDMI output.

I notice my unpowered VGA<-> HDMI adapters both ways work with no noticable ping (except maybe when light gun tested) when sound is not involved.

So convert VGA->HDMI->USB to get it in, and then use an HDMI->VGA adapter to get back to the monitor as a red and cyan anaglyph.

It just has to "feel lag free" vs playing on an actual VB.

tripletopper
Posts: 12
Joined: Sun Jun 09, 2019 1:02 am

Re: Pi baker's help wanted : 2 videos to sync

Tue Jul 27, 2021 2:39 pm

If my technique of getting 2video inputs in is correct,. Then all I need is a program which adds RGB values and displays them together as one synched frame in the HDMI output, and go from there.

Can anyone bake a Pi that takes 2 USB video inputs, and combines them RGB additively into a single video stream out? Preferably with quick enough processing to feel no delay vs playing a Virtual Boy straight.

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