[Chris Alaimo]

This is not an NTSC video signal. The video signal is not 480i doubled, and it is not interlaced. It is a 240p signal running at 60 frames per second. You are correct that RGB is color, and in this case it refers to the fact that the separate red, green, and blue video signals are carryed over separate lines in the video cable. It is colloquially referred to in the retrogaming/retrocomputing communities as “RGB video” but its proper name is “RGB analog component video”, not to be confused with Y/Pb/Pr component, which is much different. It is similar to VGA, except that it syncs at 15khz and it has a single combined sync signal instead of separate h-sync and v-cync. It is the exact same type of video signal that the Commodore Amiga and Apple IIGS computers put out, which requires a special 15khz RGB display, much like the display that I have here.

https://en.wikipedia.org/wiki/Component_video#RGB_analog_component_video

This is not a “CRT TV”. It is a 15khz RGB monitor. There is no way for me to pass this signal to a consumer TV without making modifications to the TV to allow it to accept an RGB signal. There are 4 connections on the back of my monitor, one for each color and one for the composite sync line, which a “CRT TV” does not have. The monitor has an output for each input, and this is how I am able to pass the signal on to my line doubler.

[Chris Alaimo]

Sorry, I guess I wasn’t clear about the nature of the video signal that I’m working with. I’m actually not capturing NTSC video, it’s 15khz analog RGB, and is progressive scan at 60fps, not interlaced at 30. So this is the video signal as it comes out of the graphics chip(s) in the system, but before it goes into the video encoder chip to be turned into NTSC/PAL/ETC. Almost all game systems from the mid 80’s to the mid 90’s output a 15khz 240p RGB signal since both Japanese and European TVs are designed to accept it through a SCART connection. So even though, for example, PAL is the video standard in the UK, people weren’t displaying their games that way because they were set up for RGB. Here in the states, 99.9999999% of consumer TVs do not have RGB inputs, and so we played our games using NTSC-encoded video through RF, composite, or s-video.

I run it through a device that line multiplies the signal, but does nothing to the framerate. I called it an upsaler, but that’s really not accurate because it isn’t scaling, just multiplying (I do also own an upscaler, that takes video signals and scales them to 720p or 1080p). The particular game that I was capturing runs at an oddball resolution of 336×224, at (almost) 60fps progressive. I line multiply it 4x, so I get an output resolution of 1344×896, which is what my capture device captures it at, at a detected framerate of 59.88.

Here’s a little video I shot for Twitter last week that clearly shows the resolution and framerate on the capture screen:
https://twitter.com/CGQuarterly/status/1019042322049204226

The monitor has 15khz RGB inputs on the back, so that’s what’s being displayed on the CRT screen. The video signal comes back out of that monitor, into the line multiplier, and then into my capture device.

Finally got the OSSC happy with R-Type, which it turns out runs at an oddball resolution. Time to re-record all of the gameplay footage while I rock out. pic.twitter.com/oPhrJ4gxFt

— Classic Gaming Quarterly (@CGQuarterly) July 17, 2018

[Chris Alaimo]

The project is set to 59.94. Most old game consoles output ~60fps. As I mentioned earlier, the footage in question has a framerate of 59.88, as that’s what that particular game runs at.

If I lowered the framerate of those clips to 30, I would lose the transparency effects used by most games, and the footage would look weird.

[Chris Alaimo]

Thanks, Andy. What it actually is is old video game console footage, line quadrupled through an upscaler and then captured with a capture device. So that’s why the resolution and framerate are odd.

Anyway, I will try “washing” the files through compressor and see if that helps. Thanks again!

[Chris Alaimo]

Hi Andy,

Thanks for the reply! Your intuition is correct that this footage is pretty “non-standard”. It’s 1344×896 at a framerate of 59.88 fps. You are also correct that the recording software is not locking the framerate, but rather just taking what it is getting. If that’s really what’s causing the problem, what do I do about it? Run it through compressor and have it output a file with a constant framerate?

Thanks,

Chris