Interlace artifact with TMPGenc

[John Wray]

I originally posted this in the "Archiving to CD" topic, but it doesn't really fit there, so I'm reposting it as a top-level topic.

After playing with TMPGEnc for a while now to encode to full-frame MPEG-1 from Matrox Marvel G200 MJPEG captures, I'm very impressed with its video quality, except for one problem. Every so often, in a fast-moving sequence, I get an effect that looks like two fields from different source frames have been combined into a single frame of the output MPEG-1 stream - i.e. alternate scan lines are displaced horizontally by a significant amount. The source MJPEG doesn't show this effect, so it's either an artifact of TMPGEnc, or (hopefully) something I'm doing wrong in my settings. I've tried exactly what Doc Mordrid suggested (2-pass VBR, 1850/1550/300kbps, highest quality motion search), and apart from this interlacing artifact, the output video quality is excellent. I've set the source properties to interlaced, field order B (bottom field first), which I think matches what the Marvel G200 puts out, and haven't set any filters.

Is there something obvious I'm missing?

[Sciascia]

I believe that the last version of TMPGEnc with MPEG2 support had de-interlacing in the filters, but I think that it added a "smart deinterlace" that was a little bit more selective for the blending. If not I prefer to use V-Dub in Frame Server mode to feed TMPGEnc with smart de-interlace and 2D cleaner. The difference in quality is huge. The filters in V-0Dub are a lotr more customizable and it is a fast app. You can also see the effect of the filter before rendering the whole thing. If I was you I would load a clip into V-Dub with high motion and then add some filters to it, mark the in and out points during a scene that goes from low motion to fast and then feed it to the encoder. That way you don't have to render for 2 hours to see that you should tweak it a little more.