VHS signal theory and odd errors?

[Glitchy Windows 3.1]

Hello,

This thread is as a reply to Lordsmurf. I am responding to a private message you sent me on October 6th, 2020 at 2:09PM.

Quote:

Originally Posted by lordsmurf

BTW, I can probably tell you about some odd rare errors. Not easy to recreate, but may prove interesting. As a taste, the most interesting is when the mode data is destroyed, so the tape doesn't know if it's SP, LP or SLP/EP. Weird stuff happens. But in the thread, not email, not PM.

Do you have any additional information on this? I would love to know more about "some odd rare errors" because there is not much information about VCR errors

Quote:

Originally Posted by lordsmurf

It would help to understand VHS signal theory, and I know a few books you could read.

Where can I find these books and can they be purchased online or downloaded? Would love to hear more from you!

[lordsmurf]

Buy these:
- https://amzn.to/37K0SmT (VCR Troubleshooting and Repair)
- https://amzn.to/3mn2Aik (Video and Camcorder Servicing and Technology)

When reading, remember this is THEORY -- sometimes PRACTICAL APPLICATION will vary. Experience will tell you which is which.

I want to re-read both of these myself. I have crisp new copies that I bought in the 2000s.

I'd need to ponder weird errors for a bit. Some things are so unusual that I've only seen the error once in 25 years, and others have never heard of such a thing.

The primary cause of weird errors is nth gen, often what happens when an idiot meets a cheap VCR. But not always.

Just thought of one, have samples somewhere. The interlace is visually revsed, vibrates the picture. And then randomly unreverses, re-reverses, etc. The tape must be multi-captured, advanced Avisynth shifting. You can also cheat with drop-frame deinterlace and anti-alias, which is actually not bad (but not best).

Another is DV/MPEG-type blocks ... in a VHS tape, a decade before either existed. CCD/CMOS weirdness there.

I have a lot of sample, of lots of things, just not had time to share and catalog like I want.

[latreche34]

You want to see some weird $hit? Get a recorded VHS tape, Take it a part, disconnect the tape from the spools and flip the tape upside down and reconnect it back to the spools you can only do one spool at a time and you need a way to spool it outside the VCR. and play it back.

[hodgey]

In addition to the books, this JVC Techical guide has a lot if info about how the signal is stored on tape and how it's encoded/decoded (it's a bit old, so some of the noise reduction and chroma frequency/phase compensation circuitry may have improved and changed a little later). It's helpful to have some general idea about how a standard analog composite video signal is structured to make sense of it though.

[lordsmurf]

Quote:

Originally Posted by hodgey

In addition to the books, this JVC Techical guide has a lot if info about how the signal is stored on tape and how it's encoded/decoded (it's a bit old, so some of the noise reduction and chroma frequency/phase compensation circuitry may have improved and changed a little later). It's helpful to have some general idea about how a standard analog composite video signal is structured to make sense of it though.

I see no download there, only a donate link, and instruction to send emails.
If you have this, please attach to this thread.

[hodgey]

The link is the VIDEO TECHICAL GUIDE text right of "type a", the website actually has a lot of high-res manual scans, but the interface isn't the greatest. I would attach it, but it's 120 mb and already compressed so I can't squeeze it down any further.

[lordsmurf]

I see the download link now. Thanks. Attached.