colour distortion (was: chroma artifact)

[fabweb]

If have a problem when capturing my 10 year old Hi8 tapes.
sometimes there is this chroma artifact in the top of the picture.
This problem is scene specific. As soon as a new scene starts it is gone (and eventually will return in a future scene, but I haven't found a pattern)

- This problem is not there all the time. Only in certain scenes.
- If a scene has this problem it will have it till a new scene starts.
- It is most visible on a blue or red background.
- if I pause and press play again it is GONE for the scene. (But will reaper in a future scene)
- it seems worse when using a RGB cable. (not sure abbout this, but it seems so...)

I figure that this is a head problem.
Any knowledge to better understand this problem?
Or even better: a solutions ?!

P.S. and yes, I know that it is in the safe areas and I shouldn't bother, but I do!

Capture setup:
10 year old Hi8 tapes played on a Sony EVS 9000E PAL
connected with a S-Video cable to my DV camera acting as a pass through AD converter.

[fabweb]

anybody?

At least try to give me an eyplanation how this colour distortion develops.

I had a D8 camera once and I think to remember (but only vaguely) that the colour distortion was vertically on the right side of the picture. But I cannot 100% confirm this since I do not have a recording left from that try.

Is this a head, tracking or datacode problem.

Please try to work with me here!

[JohnnyMalaria]

It might simply be the limitations of consumer analog video.

Have a read of this rather chewy article:

http://www.net-work2001.co.uk/editorsbench/documents/CF2005.pdf#search=%22pal%20%22col...0framing%22%22

It explains how maintaining the correct colour relationship between frames requires PAL video (in the analog world) to be aware of a 4-frame sequence. If your original recordings contain insert edits (or if you rewound the tape to the end of the recorded portion before starting recording again), you may break the 4-frame sequence. I've lots of Video 8 tapes that show this - when a new scene starts, the first couple of frames are often excessively purple or black and white.

Of course, I could be very wide of the mark! If so, perhaps this will stimulate someone to correct me and provide you with an answer!

[JohnnyMalaria]

Duplicate post - kept getting an error (missing recipient)

[JohnnyMalaria]

IGNORE - Duplicate post - kept getting missing recipient error and no confirmation.

[fabweb]

Thanks for your answer.

How do I correct this?

I am currently captureing all my video scene by scene!
This is a lot of work.

But since I want to convert them to 16:9 in the future, I need the overscan area....

I bought a D8 camcorder and it has exactly the same problem on the right hand side of the picture.

hmmm.

[lordsmurf]

It's most likely your player doing it. Try another player first.

[fabweb]

I tried it in a brand new D8 Player and it hast the very same kind of colour problem.
Only on the right hand side of the picture...

[fabweb]

*bump*

BTW: I still have those problems.

Any ideas on how to get rid of them?

[Alan69]

If you're competent around electronics, get an old VCR that plays well. Take off the top cover so you can get to the guides, the roller guide posts that hold the tape against the head. Left guide affects the top more, right guide affects the bottom. Per that picture if you tweaked the left post a little it'd probably be perfect. Since you have to do this with it on and playing, be careful and stay away from the power supply and wiring, and use a good screwdriver to adjust the post. Heck wear cotton work gloves for insulation or have a friend who does electron

'Tracking' essentially 'raises' or 'lowers' the read path vs the edge of the tape. By having the top of the video off but not the bottom, you can have a slight error of angle of the tape across the head between this VCR and the VCR this was recorded on. Changing one guide and not the other to match will get it done. Basically the left side of the tape is a little out of tracking even though most of the tape path is close enough.


Consider the VCR you do this to to be trash, or keep it around for similar in the future. Really you can get it back to basically where it should be easy enough, but without equipment you'll never be 100% sure it's really back at exactly the same alignment.


Note you could still have to adjust both guides for stuff like this, once you get one about right to get the angle correct you can easily have taken the overall path outside what the normal tracking can adjust for, and then need to adjust both posts up and down. Looks like you're very close here so should only need to adjust the left a tiny bit.

I had a few old tapes that barely played, looked like they were trash. Found a guide for this somewhere and started playing around, got them perfect for transfer, was just that the old VCR they were recorded on was out of alignment so I had to play around and match it..

Could be other things like in your source recording and other issues with the tape etc. But that kind of tearing only a little at the top edge is usually alignment, and it's easy to tweak some and match it. Get an old tape or two and play with changing the guides on an unimportant VCR, you'll quickly develop a feel for it. It's actually sort of fun to play around with it a bit and see adjusting the guides in action..