Issue capturing VHS recordings of 240p sources(?).

[optimumpro]

Hello! This is my first time posting on this forum, so I hope this is the right sub-forum to be posting this.

I've been having an issue capturing footage from 240p consoles onto VHS, specifically ripping them to my PC. After I capture the footage from tape (usually from my Nintendo 64 or SEGA Saturn) the footage that my PC captures looks absolutely messed up in comparison to what it should be.

This is a raw sample of footage. Note this seems to only effect games/consoles that display in 240p, my Wii & Xbox 360 capture perfectly fine. The footage also displays perfectly on things like my HDTV & my CRT, it's only displaying issues when trying to capture it for my PC.

I use a Sony SLV-N50 for my VCR, a Hauppauge USB-Live2 Video Capture for capturing to my PC (I have also tried an Elgato Video Capture with similar results), and VirtualDub 1.10.4 for the software. I've also tried multiple computers (Windows 10 & Windows 11) with no changes in results. Does anybody know how to fix this? Or what the cause of this is?
https://drive.google.com/file/d/1rJiLP9VooQC1EpYrLw487Rii8ozgw5Oy/view?usp=share_link

[rrats]

Why vhs?

[jagabo]

240p doesn't conform to the NTSC spec. Luckily for the console manufacturers CRT TVs were able to handle it. Modern capture devices cannot. A time base corrector might help.

[Skiller]

I captured plenty of 288p (PAL equivalent to 240p) off of old consoles. During capture, it gets stored like usual – 50/60 fields in 25 or 30 interlaced frames (in this case the fields aren't actually fields as the field offset of interlaced video is not there, but it doesn't matter to the capture process). No difference at all to a regular capture. However the timing of this signal is very slightly off compared to standard interlaced and some capture devices struggle with this.

All that is needed to do then is to separate the fields and you are left with the original half height frames.

[optimumpro]

240p doesn't conform to the NTSC spec. Luckily for the console manufacturers CRT TVs were able to handle it. Modern capture devices cannot. A time base corrector might help.

Ah I assumed as such, I was already planning on getting one but I guess that's pushing me to get one more. Would a VCR with TBC built-in do the trick?

[Skiller]

Ah I assumed as such, I was already planning on getting one but I guess that's pushing me to get one more. Would a VCR with TBC built-in do the trick?

No. It's not VCR related. A VCR actually doesn't care about any of this; to put it simply, it records the analog signal (basically) as-is to tape and plays it back with the same timing sync pulses that the original source had. A TBC in a VCR is a line TBC. Line TBCs do not affect what makes 240p different from 480i.


More technically speaking, the half height progressive format hack works by rounding up the two half lines that make interlaced video, well, interlaced. So in total there is one scanline more than a standard interlaced signal would have (you know, 525 or 625 lines).
To still comply with the color subcarrier frequency, the refresh rate needs to be altered as well. It is ever so slightly less than standard interlaced video. Something like 59.8261 Hz came up after a quick research. And this is what some capture devices and modern TVs struggle with, the off-standard refresh rate.

[optimumpro]

Ah I assumed as such, I was already planning on getting one but I guess that's pushing me to get one more. Would a VCR with TBC built-in do the trick?

No. It's not VCR related. A VCR actually doesn't care about any of this; to put it simply, it records the analog signal (basically) as-is to tape and plays it back with the same timing sync pulses that the original source had. A TBC in a VCR is a line TBC. Line TBCs do not affect what makes 240p different from 480i.


More technically speaking, the half height progressive format hack works by rounding up the two half lines that make interlaced video, well, interlaced. So in total there is one scanline more than a standard interlaced signal would have (you know, 525 or 625 lines).
To still comply with the color subcarrier frequency, the refresh rate needs to be altered as well. It is ever so slightly less than standard interlaced video. Something like 59.8261 Hz came up after a quick research. And this is what some capture devices and modern TVs struggle with, the off-standard refresh rate.

Ah I see, so I what you're saying is run my N64 through a stand-alone Time-Base Corrector & then plug the output into my VCR?

[Skiller]

That would repackage the video into standard interlaced 480i, yes; but to do so, the TBC will have to duplicate a field or frame every so often because the refresh rate does not match exactly. So there would be a slight stutter about every 16 or 8 seconds.
Also TBCs are expensive. I would rather find a capture device that does not struggle with 240p instead.
All of my older PCI TV tuner cards I used to use never had an issue with the non-standard 240p of old consoles.

[lordsmurf]

There are dedicated game capture cards like the RetroTINK.

But do not use it for VHS, even if others claim it "works fine", it does not. Use the right tool for the right task. Hammers with nails, screwdrivers with screws. Don't smack a hammer at a screw. There is no Swiss knife card for capturing, nothing does it all (either well, or at all).

[optimumpro]

There are dedicated game capture cards like the RetroTINK.

But do not use it for VHS, even if others claim it "works fine", it does not. Use the right tool for the right task. Hammers with nails, screwdrivers with screws. Don't smack a hammer at a screw. There is no Swiss knife card for capturing, nothing does it all (either well, or at all).

Oh yea I'm considering getting that for my main home console recording setup, but I'm looking specifically for a solution for capturing footage from tape of older consoles.

That would repackage the video into standard interlaced 480i, yes; but to do so, the TBC will have to duplicate a field or frame every so often because the refresh rate does not match exactly. So there would be a slight stutter about every 16 or 8 seconds.
Also TBCs are expensive. I would rather find a capture device that does not struggle with 240p instead.
All of my older PCI TV tuner cards I used to use never had an issue with the non-standard 240p of old consoles.

Yea I've heard TBCs can be pretty expensive. Is there a specific capture device that could do the trick instead?

[Skiller]

Since capturing 240p is a niche, it's hard to find information about which capture devices cope with it which do not.
I only have experience with older hardware (15+ years) in regards to 240p, so depending on your PC, this may or may not be an option. Any analog TV tuner PCI card based on the Philips SAA7134 or the Conexant BT8x8 is going to be fine, although I do not recommend the latter for other reasons.
The probably most common SAA7134 based tuner card is the Terratec Cinergy 400, maybe you can find one.

[oln]

I believe the I-O Data GV-USB2 also handles 240p okay.

Alternatively dvd-recorder passthrough as oft discussed though idk for sure whether devices in general end up repeating frames or something every now and then due to the slightly off frame rate.

[Skiller]

Alternatively dvd-recorder passthrough as oft discussed though idk for sure whether devices in general end up repeating frames or something every now and then due to the slightly off frame rate.

I once tried it out of curiosity and hooked up my PS1 to my Panasonic DMR-EH 575. It works but it repeats a whole frame every few seconds to compensate for the difference in refresh rate. It is especially obvious because repeating a frame that contains two consecutive half-height frames results in jittering you can't miss.

[optimumpro]

I believe the I-O Data GV-USB2 also handles 240p okay.

Really? I might consider going with that, seeing how it isn't crazy expensive.

[Bwaak]

240p doesn't conform to the NTSC spec.

I wonder how skip-field portapaks worked.