Why would I get interlacing artifacts watching on TV?

[KSJ]

In creating an SVCD, I came across the issue of "ghosting" during motion sequences, where it seems an image of a person or object in motion is trailing behind it, thus blurring the image. I was told this is an interlacing artifact, a result of 3:2 pulldown, and so I have dutifully studied up on interlacing and 3:2 pulldown from Luke's Video site, and I THINK I understand the concept. HOWEVER...

Everything I've read indicates that these artifacts are only a problem when viewing these encodes on a computer, because a computer uses a progressive display, not an interlaced display like a television does. However, I was getting these artifacts while watching my SVCD encode on a television set, played off a disc in my standalone DVD player.

Does anyone know why I would be seeing these artifacts on my television when all common knowledge says I shouldn't be seeing them unless I'm viewing the file on a computer? I tried deinterlacing, which didn't help, and the telecide filter, which also didn't help. How do I get rid of these things?

KSJ

[VidGuy]

The only thing I can think of is that you used 3:2 pulldown when the source really wasn't a FILM source - You don't mention what your source is, but if your source is really FILM, 3:2 pulldown when viewed on a TV will not give you interlacing artifacts. If you did something like used DVD2AVI with FORCE FILM set, and the DVD really wasn't FILM, this would happen.

[KSJ]

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On 2001-11-26 10:47:32, VidGuy wrote:
The only thing I can think of is that you used 3:2 pulldown when the source really wasn't a FILM source - You don't mention what your source is, but if your source is really FILM, 3:2 pulldown when viewed on a TV will not give you interlacing artifacts. If you did something like used DVD2AVI with FORCE FILM set, and the DVD really wasn't FILM, this would happen.
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My source is a PVR, connected to my capture card via S-Video, captured using VirtualDub in .avi format at 29.97 fps. The source of the signal to the PVR is digital satellite. I'm capturing a television program recorded on the PVR for archival purposes. I'm ASSUMING the source is 29.97, since it's a TV signal, but I could be wrong. I thought all NTSC TV was 29.97.

KSJ

[mpack]

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On 2001-11-25 22:26:05, KSJ wrote:
Does anyone know why I would be seeing these artifacts on my television ...
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You don't mention what MPEG encoder you are using: it kinda makes a difference. I'll assume you're using tmpgenc.

You can try the old standby: swap the field order in the tmpgenc.

You can get blurry motion and ghosting if you use the "blend" deinterlacing filter in VDub. There's really no need to deinterlace at all when making an SVCD, but if you really *must* do so then the only reliable way to do it is to throw away one of the fields, ie. use the "duplicate 1" deinterlace option in VDub.

Make sure you aren't deinterlacing twice: tmpgenc also has a deinterlace filter.

Heavy use of a temporal smoother in VDub can also cause ghosting.

[KSJ]

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On 2001-11-26 12:50:47, mpack wrote:
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On 2001-11-25 22:26:05, KSJ wrote:
Does anyone know why I would be seeing these artifacts on my television ...
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You don't mention what MPEG encoder you are using: it kinda makes a difference. I'll assume you're using tmpgenc.

You can try the old standby: swap the field order in the tmpgenc.

You can get blurry motion and ghosting if you use the "blend" deinterlacing filter in VDub. There's really no need to deinterlace at all when making an SVCD, but if you really *must* do so then the only reliable way to do it is to throw away one of the fields, ie. use the "duplicate 1" deinterlace option in VDub.

Make sure you aren't deinterlacing twice: tmpgenc also has a deinterlace filter.

Heavy use of a temporal smoother in VDub can also cause ghosting.

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Sorry...I tend to err on the side of caution when it comes to providing too much unnecessary information.

The full story:

I have used both TMPGenc and CCE and gotten "ghosting" with both of them, without using ANY filters. Swapping the field order led to a jittery picture. Using "bottom field first" gives me a fairly smooth picture, but without any filters or deinterlacing at all, I had ghosting. I only started using filters to try to correct the ghosting.

I tried the general deinterlace filter on "blend" settings with no noticeable improvement. I tried the Smart Deinterlacer with the default settings with no noticeable improvement. I tried Telecide with no noticeable improvement. The dynamic noise reduction filter (which I tried using for reddish "graininess" in the backgroung) made the ghosting worse.

I tried to do a regular VCD encode (using TMPGenc, since I can't get Panasonic to work on my new system) rather than SVCD and didn't notice any ghosting. But the picture was still "noisy" and so I applied the noise reduction filter. This led to *some* ghosting, though not as bad as I noticed on the SVCD encode.

KSJ

[tdc99]

KSJ, I think I'm having problems similar to yours. I've got digital cable and I notice that, regardless of the show, all of my vid captures are telecined. At first I thought: no problem, I'll IVTC the source and create a 24 fps SVCD.

Unfortunately, I still get some intermittent jittering - even after IVTC. (Granted, the IVTC processed file is FAR better than the original capture.)

I hate to sound paranoid, but do you think that my digital cable company is first turning a 30 fps signal into a 24 fps (progressive) signal before transmitting it to me? (Then doing a telecine encoding on that signal once it's received at my box?)

If so, would this account for the jittering after I've done the 3:2 pulldown?

I'm new to this 24 / 30 fps issue, so any insights would be greatly appreciated.