Strange effect. How do I cure it

[jrsdsl]

I not sure what the proper term for this effect is but I did a capture from TV with Vdub and the VCD was done with Tmpgenc but during some scenes where people are moving around you can kind of see where they just were-if that makes sense. The motion isn't fluid. Low motion scenes are ok. Can this be fixed and how?

thanks

[Vejita-sama]

Could be a lot of things. What resolution did you capture in? It sounds like interlacing. If so, then you can fix by either capturing at ???x240, deinterlacing, or encoding to MPEG2.

[jrsdsl]

I probably did't need too but I captured at 720x240 uncompressed. My system (PIII 700)oddly dropped a lot of frames even with mild compression and I had the disk space to spare then.

[kinneera]

What you describe sounds like interlacing artifacts, which is odd since you captured at 240 vertical lines. I don't know then what exactly is the problem, but I thought I would mention for future reference that you're better off raising the vertical resolution before the horizontal resolution in terms of image detail (ie 352x480 or 480x480 is probably better than 720x240 for almost all purposes). In fact, 720 is almost always overkill, since DVD is about the only source material that really represents that much horizontal resolution detail anyway.

[jrsdsl]

Thanks for the info. I guess I don't understand why you have to deinterlace an interlaced source just to watch it on TV another intelaced medium. Oh, well. I did apply a deinterlace filter in Tmpgenc (Even field) and now the body movement of the actors in the clip don't leave little "trails" behind them but the quality now isn't as good as before. The clip is a litte blurry now and I can see blocks I didn't see before. Is this what I have to live with to cure the interlacing problem? There were a lot of choices for deinterlacing in Tmpgenc filter. Should I have chosen another one? How do you know which one will suit your situation.


thanks

[kinneera]

It's very odd that your capture card is retaining interlacing at 240 lines. If you want to correctly retain the interlacing, you should capture at 480. Deinterlace filters will also behave better with the extra lines, I would think.

[jrsdsl]

The deinterlacing filter in Tmpg seemed to help the "trails" during rapid movement but now another problem has developed. There seems to be some pixelation on objects in a distance. Is this natural? Also, the edges of objects, ie, doors move or shimmer-I guess that's how I would try to describe it. How do I handle this?

thanks

[kinneera]

Shimmering is typical of interlacing (sometimes you can even see this on your TV where there are sharp horizontal lines or text). A double (blur) deinterlace filter will average two frames to generate a median that might have less shimmer, but it will also make the video softer, so its sort of up to you what you prefer.

As for pixelation, that is probably just the effect of MPEG encoding at a low bitrate. It beats having blocks anyway, and will probably not be terribly noticeable (if at all) on your TV.