Interlacing artifacts on poor VHS conversion

[binister]

I have captured a very old VHS tape that is exhibiting some strange interlacing artifacts when played back on my TV.

For reference, all of my other captures/conversions look fine.

The tape has some major compounded TBC errors on it and I am wondering if that is contributing to the problem. I have only done some minor level tweaking on the footage but the resulting DVD exhibits obvious interlacing artifacts (combing) when played back on a TV. If I play the DVD in VLC I see the same artifacting until I enable the blend deinterlacer at which point the footage is properly deinterlaced and the artifacts disappear.

It is almost as if the DVD footage isn't flagged as interlaced or something. Both my LCD and plasma sets don't appear to be deinterlacing the footage. I really am at a loss as to what could be preventing my LCD and plasma to not deinterlace the footage. Any ideas?

[binister]

I should also mention that the interfacing artifacts are on the same horizontal plane as the TBC errors.

Other portions of the video do not seem to suffer from the artifacts.

[jagabo]

I suspect you encoded interlaced video as progressive rather than interlaced. Recommend you post small samples of the source and VOB.

[binister]

Here are the clips.

1. HuffyUV encoded DV AVI (16 MB).
http://rapidshare.de/files/39897088/post.avi.html

2. MPEG2 encoded (via CCE) .mpv file (1.4 MB).
http://rapidshare.de/files/39897104/post.mpv.html

You can see the artifacts on the borders of the curtains and sliding door in the back when these clips are played back on a DVD player. Notice the significant TBC errors along that horizontal plane.

I checked the frame parity of all clips with GSpot and they are all interlaced BFF clips.

I downloaded Smart Deinterlacer for VirtualDub to see if I could recreate the problems in VDub and it looks like it might just be a limitation in my HT DVD players. If I set the motion detection value to a low number (meaning small interframe movement is deinterlaced) then the clip looks correctly deinterlaced in VDub. If I set the motion detection value to a high number (large movement required for deinterlace to occur) then I see the same artifacts that I see on my HT screens.

The deinterlacer in my DVD player and PS3 must be using an adaptive deinterlacer that isn't sensitive enough. I know they are doing some deinterlacing because obvious movement is deinterlaced.

Thanks for the help.

[jagabo]

I didn't check the HuffYUV file but the MPG file is indeed encoded 29.97 fps interlaced, bottom field first, and does contain bottom field first frames. So everything looks good at that point.

The last thing to check is to make sure that the video was authored as BFF. Check the VOBs and IFO.

You could also try converting to TFF with CCE and making a TFF DVD. Maybe your DVD player and TV will be happier with that.

I don't think any smart deinterlacer will do a good job with the severe time base errors in that video. If you have to deinterlace you might try just dropping a field and resizing what's left. In VirtualDub that would be Deinterlace -> Drop Field 1 (or 2) followed by resizing back to 720x480.

[binister]

Thanks, yeah I think the time base errors in the video are indeed the problem. I tried converting to TFF and the results are the same. I have also verified the correct field parity in my VOB files using GSpot.

Dropping a field would reduce the overall resolution by half right?

I think I will just live with the poor deinterlacing and leave the source as it is.

Thanks!

[jagabo]

Dropping a field would reduce the overall resolution by half right?

Yes, but the video (at least the small sample you supplied) is so blurry you may not even notice.

If you're archiving you want to save as much as possible. Maybe a future player/TV will handle the video better. But a second, drop frame deinterlaced, version for watching might be useful until then.