VHS to DVD-R (noise on DVD-R playback)

[Endgroove]

Fine Minds:

I'm using a Sony DVP-S500 VHS player (via S-Video out) to a Pioneer DVR-7000. I'm recording to DVD-R media (Verbatim & Emtec) using the DVD-Video format.

The playback from the VHS is clean. On the other hand, when I record to DVD-R and play it back I get an entirely clean picture EXCEPT for about a half inch strip of noise along the very bottom of the picture.

Any theories?

Regards,

Sean Lavery

[piano632]

What you are experiencing is called "head switching noise" which is caused by the VCR constantly switching between video and audio heads. Unfortunately, there is no way to fix this - it happens with any digital capture from analog tape. You just have to live with it or if it really annoys you, you can crop off the bottom of the picture with certain computer software - but either way the bottom of the picture gets lost.

[Endgroove]

"it happens with any digital capture from analog tape"

Hmmm. I guess this would explain why I got similar results transferring VHS (from the same machine) to DV on a composite connection. But REALLY? I mean ANY digital capture from analog tape?

It just seems incredible to me that an engineer would design this product knowing full well that the core user of this kind of machine MAY want to transfer a VHS tape or two at some point...

I'm pretty positive that AVID doesn't suffer this problem either. Oh well.

thanks for your quick response!

[housepig]

It just seems incredible to me that an engineer would design this product knowing full well that the core user of this kind of machine MAY want to transfer a VHS tape or two at some point...

I don't think it's a defect in the capture hardware, rather a by-product of technical limitations of VHS.

- housepig

[solarfox]

It's not the capture device's fault, Endgroove -- it's faithfully capturing exactly what's being sent to it by the VCR. The reason you don't see it when playing the VHS tapes on your TV set is that all televisions are typically adjusted so that the picture is actually expanded slightly beyond the physical edges of the monitor tube -- i.e., the "overscan" region -- and the head-switching occurs in this area. If you were to open up the back of your TV and adjust the vertical-size control so that the entire picture fell within the screen area, you'd see it there, too.

All you can do is crop it. The good news is, if you pick your cropping settings correctly, the "lost" image area will be out in the overscan as well, so you won't notice that it's gone. (And it keeps the MPEG algorithm from wasting bitrate on the meaningless frame-to-frame noise.)

(Piano632 -- actually, it's caused by the VCR switching from one video head to another as the drum rotates, not by switching from audio to video heads. The drum has multiple heads which are accessed in sequence, since each one is only in contact with the tape for a certain portion of the drum's 360-degree rotation.)

[Endgroove]

This forum rocks!

I totally understand now.

Cool. I just bought the Pioneer, and couldn't figure out why my DVD's were not playing the same on my computer as on my TV... It all makes sense now though.

Now here's another question: Is even it possible to crop as I capture? The DVR-7000 appears to have no such capability as far as I can tell. Please share what gear setups you would use to do this.

Again thanks piano632, housepig, and solarfox for your informative posts.

Much appreciated

[solarfox]

I don't think you can do it with a set-top recorder, no.

Generally, I capture to the hard drive with an analog-to-DV converter, then use ULead Media Studio Pro to crop the image while it encodes to MPEG-2. (There are other programs which can do this, though; I just use MSP because its what I happen to have.)