Problems with flashing colours on VHS/SVHS capture

[nick1977]

Hi all

Looking for some advice.
I have a DV Xtream Pro 7230 which I have had for a couple of years http://www.aviosys.com/dvxtreampro7230.htm
Essentially it is a device that lets you input composite, s-video and component and converts to DV-AVI

In the past I have be capturing S-Video signals from my Sky+ box and have been impressed with the results.
The other day I decided that I wanted to get rid of my VHS, but keep a few bits and bobs for posterity.

However, when I capture from both my VHS VCR, and my SVHS camcorder, using S-Video or Composite, I get really bad colour flashing, making the video pretty much unwatchable. Playing back in virtualdub, it seems to alternate from frame to frame, with half the colours in 1 frame being right, and half in the other being right. Other times, one frame is completely right, and the next is completely wrong.
If I capture from the camcorder when it's showing "Live" footage it's fine, but as soon as you press play and the tape kicks in the colour goes crazy.
If I use the motion blur filter in virtualdub about 3 times, the colour is almost stable and correct, but obviously the motion is incredibly blurry by that point.

Anyone know what's going on?
Could it be tape noise causing the problem? I think it's less noticeable on tapes that are good quality, although it was very bad on SVHS-C tapes that were first generation. I tried a clip from a commerical VHS from 2002 and it was far less obvious, although still there slightly.

If necessary I can get some screen grabs, but that will have to wait until I get home.

Thanks for any advice!
Nick

[edDV]

I never heard of that model but I have a similar Canopus ADVC-100.

Is it possible you have it switched to NTSC mode?

PAL (phase alternate line) video alternates colour phase each field so that phase errors tend to average for each frame*. This was supposed to correct the phase drift characteristic of early NTSC (some say never twice same colour).


* extreme phase (hue) errors in PAL cause chroma line to line saturation errors.

[nick1977]

Thanks for the response

I was thinking it may be something to do with the PAL/NTSC.
The device is supposed to switch automatically between them, and the output file is 720x576 25fps. However I do have my suspicions that something in the hardware is getting confused with the input signal.
I have tried changing the switches to force PAL mode, but the manual is written by someone in Tiawan so isn't the easiest thing to follow! Not sure if I did it correctly or not...

Is it worth me trying to post a few stills to show the problem?

Nick

[edDV]

Wouldn't hurt. Remember Taiwan is an NTSC country so they may not have adequately tested with PAL.

[nick1977]

Here's a few screen grabs

The first image is frame 1, then frame 2. The last image is virtualdubs motion blur filter output after 3 uses.
As you can see, apart from looking a bit washed out, the colours are pretty accurate on that one.
Also the image detail levels are pretty good for 20yr old camcorder fottage. The colour is the problem...

The final image at the bottom is a screen grab from my Sky+ box, which shows that colours are 100% accurate when coming from a "clean" source.


[Attachment 647 - Click to enlarge]
[Attachment 645 - Click to enlarge]
[Attachment 646 - Click to enlarge]



[Attachment 648 - Click to enlarge]

[danno78]

If is fine on live and bad when you play tapes then I guess is something related with time base errors or false macrovision detection. If your camcorder and vcr have TBC turn the feature on or get a external TBC to stabilize the signal.

[nick1977]

Thanks for the advice.
If I was to buy a secondhand SVHS deck with a TBC in it (some come up on EBay now and again) would this act as a passthrough for the playback of my camcorder, applying the TBC in the process, or are VCRs with TBC generally only able to apply the TBC on tapes played back with the machine itself?

Nick

[edDV]

Usually the latter.

Attachments aren't working here.

[danno78]

are VCRs with TBC generally only able to apply the TBC on tapes played back with the machine itself?

Yes. TBC from these vcr don`t work in passthrough mode. Are available only for playing tapes. Some DVD recorders (Panasonic ES10, ES15, EH57, some Pioneer models etc) have TBC inside and work in passthrough mode.

[nick1977]

Usually the latter.

Attachments aren't working here.

OK thanks
Funny the attachments didn't work on my brothers laptop, but they work fine at my workplace.

Nick

[nick1977]

are VCRs with TBC generally only able to apply the TBC on tapes played back with the machine itself?

Yes. TBC from these vcr don`t work in passthrough mode. Are available only for playing tapes. Some DVD recorders (Panasonic ES10, ES15, EH57, some Pioneer models etc) have TBC inside and work in passthrough mode.

Thanks for the info. I'll think about getting (or ideally borrowing!) a DVD recorder for this purpose. I assume using the passthrough and applying the TBC doesn't involve a conversion to MPEG?
I ideally want to capture a lossless signal converted to DV rather than an analog to MPEG to analog converted to DV (if that makes sense!)

Nick

[danno78]

I assume using the passthrough and applying the TBC doesn't involve a conversion to MPEG?

You're right. Output will be free from mpeg artifacts. Passthrough mode with Panasonic bypass mpeg encoder.

[nick1977]

Thanks.
I'v had a look at the online manual for the ES10 UK Model.
It doesn't mention a TBC specifically, but does mention Noise reduction for AV inputs
It's on page 27 of this pdf:
http://tda.panasonic-europe-service.com/docs/2z4b90d156z3z21469z656ez706466z20zd41f2e3...3B_engl_UK.pdf

Is that what I should be turning on, or is the TBC somehting which is always on and they don't even mention it?

Nick

[danno78]

TBC from ES10 is always on. Noise reduction is another feature that can be set on or off.

[lordsmurf]

It's not a TBC in the ES10, it's a special filtering circuit. Panasonic had a name for it, though I forget.
Read more about TBCs here: http://www.digitalfaq.com/forum/showthread.php/alternative-avt-8710-1853.html?p=9889#post9889

[nick1977]

Cheers.
One last question!
Do all Panasonic DVD-Recs have built in TBC?
My Dad has one, but it's an earlier model circa 2001. DMR-E50. If that has one I'll borrow his

*EDIT* Sorry, Lordsmurf, didn't see your repsonse before responding.
Thanks for the link. I don't really want the expense of a full blown TBC, as I only have a handful of tapes to copy. I'll try my Dad's E50, and failing that an ES10 (can get one for about £20) and see how it goes...

Nick

[danno78]

Time base correction and frame synchronizer mean DIGA in Panasonic language. Today DIGA have more and more features. Look at this post and see what can do TBC built-in from ES10:
https://forum.videohelp.com/threads/299682-Wavy-video?p=1837208&viewfull=1#post1837208

[nick1977]

Thanks all fo rthe advice.
I will report back once I have some more news

Nick

[lordsmurf]

Diga is the branding for their encoding method (including that stupid 4-hour 740x480),
not the DNR/sync filtering system.

[danno78]

VHS Refresh dubbing to DVD

Many of us have whole collections of home movies and other content on VHS tapes. However, as we enter the high definition age VHS recorders are becoming something of the past - accordingly many people are looking for ways to transfer their VHS collections to DVD.


Look no further! VHS equipped DIGA DVD Recorders are great tools for VHS archiving. Not only can precious footage be archived on DVD, but you can actually improve the picture quality of your old VHS recording during the archiving!
The VHS Refresh Dubbing feature utilises two technologies that literally 'clean-up' the signal from the VHS tape. The Time Based Corrector reduces the jitter commonly found on ageing VHS recordings whilst the 3D DNR technology detects and eliminates randomly generated noise and colour irregularities. Now VHS recorded memories can not only be saved onto DVD, but images are improved for future enjoyment.

From Panasonic site:
http://www.panasonic.co.uk/html/en_GB/Products/DVD+Recorders+%26+Players/Technology/DI...#anker_1817209

So, TBC is a part of DIGA. Diga has become a brand name for their recorders with many features added. Panasonic recorders base on own IC design (Matsushita chip) have TBC inside. Some of them work in passthrogh mode. Many users have found that ES10 have TBC bult-in. Period.

[danno78]

Cheers.
One last question!
Do all Panasonic DVD-Recs have built in TBC?
My Dad has one, but it's an earlier model circa 2001. DMR-E50. If that has one I'll borrow his

*EDIT* Sorry, Lordsmurf, didn't see your repsonse before responding.
Thanks for the link. I don't really want the expense of a full blown TBC, as I only have a handful of tapes to copy. I'll try my Dad's E50, and failing that an ES10 (can get one for about £20) and see how it goes...

Nick

On paper all have TBC. On practice, not all. Some Panasonic are base on other chip/tehnology and these can perfoms differently. You should make a test and see if E50 can help. For £20 ES10 would be the cheapest TBC.