Help with a VHS Project/Understanding VHS

[Anonym00se]

So after I record the vhs tape (720x540) I digitize the tape as 720x480and resize to 1440x1080. Is there a way to avoid the 16 pixel cropping?

[The 14th Doctor]

Well the active picture area is 704x480, so you'd just be cropping the added black bars from the capture card itself. That's to I believe help with preserving the proper aspect ratio

[Anonym00se]

So capture the tape as 720x480, crop to 704x480, and resize to 1440x1080?

[Alwyn]

Ok, so export from After Effects as 720x540 29.97i, square pixel ratio? (1:1), burn it to dvd (it squishes to 720x480, and when I record it onto VHS it should correct itself to 720x540.

Yes. The capturing and post-processing of the VHS tape is, of course a completely different issue. The main thing, at this point, is to get a proper 4:3 image onto the DVD and then onto the tape.

[Anonym00se]

When I try to export 720x540 as 720x480, theres pixels on either sides, that’s normal right? The tape will correct it?

[The 14th Doctor]

Hm, I believe those black bars would then be included on the tape, along with the black bars adding by the capture card. So that's just making it worse..

I think you'd be able to export it as 720x540 and use something like DVDStyler to make the video be DVD compatible

[dellsam34]

When I try to export 720x540 as 720x480, theres pixels on either sides, that’s normal right? The tape will correct it?

I think what's screwing your project is the rec.709, NTSC digital should be rec.601.

[Alwyn]

When I try to export 720x540 as 720x480

Don't export as 720x480. The square pixel frame of your work is 720x540, so just export as that. Then add that 720x540 file to your DVD authoring program and it will code it correctly. Then you can play that DVD into your VCR for recording.

[Anonym00se]

Ok, so export as 720x540 square pixel 29.97i (or 59.97p) and the dvd/vhs does the rectangle pixels? Nothing to change on my behalf?

[Anonym00se]

And regarding Rec. 601, you think I should take that into account?

[Alwyn]

I'm not a whizz on 601/709, but my understanding is that if your video is less than 720 vertically, then it should be 601. If it's 720 or more vertically ie "HD", it should be 709.

I stand to be corrected by the colour experts.

[Anonym00se]

As for dvd authorizing software, any recs? I was just gonna burn the video files to DVD-RW, but it seems that’s incorrect and the authorizing software correctly resizes the video and other stuff.

[Alwyn]

DVDStyler is a free DVD Authoring program. Not the easiest program to understand, but very few are!

But provided your DVD player will play standard video files eg MP4s, it will probably be able to output them to your VCR, so there would be no need to "author" the DVD. Try putting a file onto a DVD and playing it. If that works, it'll save you the pain of authoring a disk.

[Anonym00se]

Alright, I’ll try burning the files to the dvd first. As for my method, (720x540 square pixel 29.97i (or 59.97p) and the dvd/vhs does the rectangle pixels? Nothing to change on my behalf?) does that work?

[Alwyn]

the dvd/vhs does the rectangle pixels? Nothing to change on my behalf?) does that work?

When you capture from the VCR, yes, the digitiser/capture software will create the rectangular pixels.

[Anonym00se]

Ah! Ok, so 720x540 square pixels into the vcr, digitize at 720x540. As for the rectangular pixels, did those ever matter to begin with? I’m curious as to why the medium uses rectangular pixels anyways.

[Alwyn]

digitize at 720x540

Coming out of the VCR, you'll digitise at 720x480 because that's how your (all) digitiser generally works.

I’m curious as to why the medium uses rectangular pixels anyways.

Good question. Technical reasons with old CRT TVs, I suspect.

[jagabo]

I’m curious as to why the medium uses rectangular pixels anyways.

The best analog video had about 500 lines of horizontal resolution across the entire width. Adjusting for a Kell Factor of 0.7 gets you to about 714. So to effectively reproduce the the analog picture in round trip from analog to digital and back to analog without moire problems requires about 714 pixels. It was rounded to 704, a nice mod 32 frame size. Then 8 pixels worth of the analog signal at the left and right were also captured in case the source or capture was slightly off center.

https://en.wikipedia.org/wiki/Kell_factor