jitter on capture, but not on tv?

[tn-xyz]

hey everyone!

i'm new here and don't have the in-depth knowledge about digitizing vhs and, frankly put, i need your assistance. please spare with me.

i'm trying to digitize a couple of home videos, using a blaupunkt rtv-965, s-vhs, elgato video capture via virtualdub and the huffyuv codec. my issue is that i get hoizontal jitter on the actual digital picture whereas it plays just fine on tv (played side by side). not constantly, but when the person filming is moving.

i really don't know what issue is. is it the output from the vhs recorder/player or the elgato hardware?

when i adjust the tracking in real time, it's visible on tv as well as on my computer.

i'd be really grateful for any advice you're willing to offer.

best regards,
tn

[DB83]

No replies. So allow me to add some words to this thread.

'Jitter' is rather a 'broad statement and could means one of several issues. And even more than one together. ie Time-Base issues, interlacing artifacts etc. etc.

What I would suggest is that you upload, as an attachment direct to this thread, a short sample of the issues you are experiencing - 10/20 seconds should be sufficient to assess.

[tn-xyz]

thanks a lot, DB83 for your reply.

i will provide a sample, possibly tonight or tomorrow.

[tn-xyz]

here's a short sample of the particular passage.
i've got these on a couple of tapes, but only when movement during filming was too hard.

[jagabo]

That might be the capture device's Macrovision detection (falsely) kicking in. A time base corrector may fix it.

[tn-xyz]

That might be the capture device's Macrovision detection (falsely) kicking in. A time base corrector may fix it.

do you think an ES10 in pass-thru would suffice (at least to try) or do i have to go all the way with an ATV-8710 / CTB-100?
the former i could get for little money.

[DB83]

Could I ask one question.

Pls confirm that you are actually in PAL-land and have not inadvertingly captured NTSC 30fps as PAL 25fps.

As far as the tbc issue is concerned, pass-through AFAIK does help with standard time-base issues but these are not standard - you would even see these in the early footage. Macrovision correction requires a full-frame tbc and not a line-tbc. Pass-through is of the line variant.

The problem here IMHO is that there is no guarantee that the tbc will correct it.

[tn-xyz]

yes, i'm in PAL-land.

after reading and thinking about your statements i have little hope that i can fix those distortions with an ES10, however, i will try, because right now it's the cheaper route to go.

nevertheless, do you have any tips on how to obtain one of those preferred full-frame TBCs in europe?

[jagabo]

But this isn't real Macrovision. The timing cleanup done by the ES10 may be enough to eliminate the problem. Another possibility is to get a capture device that ignores Macrovision. But you'll still benefit from the line TBC in the ES10.

[DB83]

^^ Now I know for a fact that my old pci-based Hauppauge capture card ignored mv. Now if I only lay my hands on that tape to test it on my usb2-live !!!

But I have found that fake mv can be a beast.

[Brad]

These are timing errors caused by the recording mechanism being jolted with every step that the camera person took. Also, while it's watchable before they start moving, you can easily see the borders wiggling from lack of TBC.

I saw the exact same error on one of my own tapes, and both DVD recorder passthroughs that I tried corrected it without issue (just as your TV is).

Similar wackiness can be seen in this video when he starts abusing the playback drum. He's showing it on a broadcast monitor that allows switching the AFC speed so that jitter isn't hidden like a consumer CRT.

[tn-xyz]

again, thank you for all your assistance!

i got my hands on an ES10, set it up in pass-thru mode and voilà -- it fixed the issue!
i attached another sample.

by its nature, the ES10 cuts off a few pixels on the left, but i could live with that.

however -- and i don't know what the proper term is -- the horizontal line (timing error? tracking error?) at 2.280 bothers me.
is there any way to fix it?

vaporeon800, do you think it's still to wiggly?

[jagabo]

I don't see the new sample.

[tn-xyz]

i submitted my reply too quickly. it should be there now.

[DB83]

Glad to read that a simple pass-thro has solved your issue.

I don't see any real issues with the new capture. Are you referring to the typical head-noise at the bottom of the picture ?

That would not be seen on a tv since it is then masked by overscan. If it really bothers you, you could crop it away but then you destroy the precise AR. Or you can add a small black border.

Unless you are referring to something else which my one good eye did not see.

[tn-xyz]

the bottom doesn't bother me.

it's the line in the upper part of the video.
i should have posted a screenshot in the first place, sorry for that.

[DB83]

It's more pronounced in the video than the still suggests.

Someone might suggest a filter to help to remove it. But if it only happens this once I would not be that concerned. I assume you did not see that on the tv screen.

[tn-xyz]

actually, i did see it on the TV screen before the ES10, but i was more focused on the timing errors.
but, you know, once the video gets cleaned up you look at the "dirt" that is left...

[jagabo]

however -- and i don't know what the proper term is -- the horizontal line (timing error? tracking error?) at 2.280 bothers me.
is there any way to fix it?

There are several ways to fix it. You can copy parts of the prior or later frames, motion interpolate from earlier/later frames, some noise filters may be able to remove a lot of it. An AviSynth script like:

SeparateFields()
top = SelectEven().RemoveDirtMC(100)
bot = SelectOdd().RemoveDirtMC(100)
Interleave(top,bot)
Weave()

eliminates almost all of it.


[Attachment 41226 - Click to enlarge]

That RemoveDirtMC setting of 100 is pretty high so I would limit it to only the frames that need it.

One thing you should check before you go on is the black level of your caps. Without TBC vs. with TBC:


[Attachment 41227 - Click to enlarge]

Note how the darks aren't as dark after the TBC. There are settings in the ES10 that control the black level (NTSC setup) for both the in put and the output. I think you need to set the input to "darker".

[jagabo]

By the way, you're capturing interlaced video but encoding it progressive. That will cause obvious ghosting on highly saturated colors when there is a lot of motion. If you're going to be doing any cleanup you should capture with a lossless codec, then do the cleanup and compression.

[DB83]

^^ But didn't the OP already state that the original capture is lossless ?

My take is that the sample was merely to highlight the disturbance.

[jagabo]

^^ But didn't the OP already state that the original capture is lossless ?

You're right. In the first post he said he's using huffyuv.