QTGMC jittering on some videos

[BillyJeanB]

I'm having a problem with some videos from VHS which are a bit shaky, where QTGMC makes them extremely jittery. The raw file is a bit jittery but QTGMC is making it a lot worse, see here, (Left side is interlaced, right is QTGMC) https://youtu.be/EyWlIJrNBCs

QTGMC works fine otherwise on non-jittery tapes

[Attachment 50724 - Click to enlarge]

[Attachment 50725 - Click to enlarge]

There must be some setting or something causing it to be so bad? Also if anyone knows how to make the tape jitter less that is also helpful. It isn't too bad, tracking helps reduce it to a bearable amount. It is recorded in EP mode. I run the composite through a DMR-ES15.

[jagabo]

Post a sample of your source -- not reencoded. But you certainly need to use ConvertToYV12(interlaced=true). That's not the cause of your jerkiness though. The source filter almost certainly the cause of that. Try using DgIndex and Mpeg2Source() instead. Or LWlibavVideoSource(). Or try running ffmpegsource2() single threaded.

[johnmeyer]

Are you 100% sure that it is top field first (TTF)? It obviously should be if it is HD, but if that is somehow BFF, you could get artifacts like what you describe. I always test interlaced sources for field dominance by walking through the video for a few frames, one frame at a time, through this script:

AssumeTFF()
Separatefields()

If you see the video shuffle back and forth, rather than progressing smoothly from one frame to the next, then the field order is wrong.

Also, I would temporarily disable any and all multi-threading until you get it working. It is sometimes possible for AVISynth to read frames out of order when multi-threading.

However, as jagabo says, it is tough to come up with a better solution until you post a short, unprocessed clip.

[BillyJeanB]

Post a sample of your source -- not reencoded. But you certainly need to use ConvertToYV12(interlaced=true). That's not the cause of your jerkiness though. The source filter almost certainly the cause of that. Try using DgIndex and Mpeg2Source() instead. Or LWlibavVideoSource(). Or try running ffmpegsource2() single threaded.

Thanks. I added that part about the interlacing.

I did seem to figure out the problem. I set the audio track to -3 (so no audio) and now it comes out fine. If you still want a sample let me know. But the way I am going to eventually work on the videos having it render without the audio is perfectly fine because I am going to work on the audio separately then combine it with the deinterlaced/edited video. I also checked to see if the two versions with and without audio ended up being different lengths and no they came out exactly the same so that shouldn't be a problem.

Also, does anyone know if a proper TBC could fix the jittery tape (it is shaking vertically)? If so, any specific recommendations? I am extremely happy with the DMR-ES15, especially for the price, but perhaps a proper TBC would fix that? It only happens on that one tape, only some recordings on it so I'm not too concerned.

Thanks for the help.

[jagabo]

I'd still like to see a clip that generates the same problem. It would fit in with my archive of unusual and problematic clips.

A standalone full frame TBC may or may not fix the problem. But you can probably fix it in AviSynth with a filter like Stab().

[johnmeyer]

Also, does anyone know if a proper TBC could fix the jittery tape (it is shaking vertically)? If so, any specific recommendations?

Once again: post a clip!! There are many, many artifacts which can be described as "jittery," but only some are caused by time base errors.

[BillyJeanB]

Here is a clip, where you can see the jittering. I will try that plugin, thanks. Tracking made it better or worse but that is as best as it got by adjusting it.

[johnmeyer]

It looks like the clip has been noise reduced. If not, turn OFF any noise reduction that is built into the VCR. Also, the VCR should always have ALL enhancement circuits turned off. In many VCRs this is done by turning ON the "Edit" function. Consult the manual for your VCR. You actually want to capture that noise and then eliminate it digitally because the noise reduction in VCRs is extremely crude and very destructive to detail. Doing it as I recommend will make a big difference.

As for the shakiness, it might be cured by using a VCR which contains a TBC, or by using an external TBC, but then again, it might not. TBC errors, in my experience, tend to be a little more regular. By contrast, this seems to come and go.

Before you spend money on any more equipment, here are some things to try:

1. Turn OFF any TBC or "stability" function in your VCR. On some of my semi-pro Panasonic VCRs, this so-called TBC actually makes stability worse.

2. If this is an EP (6-hour) recording, experiment with any functions in your VCR that are designed to "stabilize" such recordings. My JVC & Philips VCRs have such settings and sometimes they help, but other times they can actually ruin footage that is pretty good.

3. Learn how to manually change the tracking for your VCR and play around with that. If this problem only happens in a few places, I have had good luck by first capturing the entire tape, and then going to sections that have problems and re-capturing with the tracking "tuned" until the jumps disappear. If you have hundreds of places where this happens, then this may not be an option. However, you also have the option of doing two captures: one with auto-tracking and the other with your manually tuned tracking. Put them both on the NLE timeline and then simply cut between the video whenever there is a problem.

4. Try another VCR.

[jagabo]

This worked pretty well in the early part of the video where the camera is still but doesn't do much once the camera starts moving.

Mpeg2Source("Clip.d2v", CPU2="ooooxx", Info=3) 
SeparateFields()
even = SelectEven().Stab(dxmax=0, dymax=2)
odd = SelectOdd().Stab(dxmax=0, dymax=2)
Interleave(even, odd).AssumeFieldBased().AssumeTFF()
Weave()
QTGMC(preset="fast")

[BillyJeanB]

It looks like the clip has been noise reduced. If not, turn OFF any noise reduction that is built into the VCR.

Yes that was probably the passthrough of the DMR-ES15, I'm not sure but I think I had the NR on when I did that test. I am going to capture with it off once I have better capturing stuff, Right now I'm just testing. I do have Neatvideo which I lovee.

jagabo, Thank you for that. I will give that a try. It is great how many options there are for fixing it, some easier/better than others.