help on the "avi jerk"?

[maca]

I've been encoding video for quite a while and have found a way around most problems. But one that still stumps me is the one I call the "avi jerk". You know, when you get an avi which has that little stutter in the video about once per second, not noticable in a dialog scene but really becomes apparent when there's a pan or some other action.

No encoder I've tried seems to be able to smooth out the motion of such avi files. Does anyone have a hint, or are these files just badly created and beyond help?

[guns1inger]

What is your process ?

If you use a one-click-wonder tool that converts 23.976 fps NTSC to 29.976 fps NTSC, instead of simply applying a pulldown flag, you will get jerk because of the extra frames being created. The best way is to use an encoder to encode at 23.976, then use DGPulldown to add the pulldown flags before authoring.

Conversions between formats can also produce this type of effect because of frames either having to be created or deleted to match the new speed.

[mats.hogberg]

To my ears it sounds like a bad PAL/NTSC conversion. When and where is impossible to say - It can be anywhere from the first reencoding to the DVD player doing the conversion (badly) before sending the signal to the TV.

/Mats

[lordsmurf]

Sounds like deinterlace.

[jlietz]

I had a problem once where I thought there was something wrong with my video (https://www.videohelp.com/forum/viewtopic.php?t=191216&highlight=), but it turned out it was some combination of my system, video card, and software player. Viewed on another system the video looked fine.

Have you viewed the avi on another system or with another player?

[maca]

To the first reply, I don't use a "one click" program but whatever variety of programs that do the best job. Usually VirtualDub and TMPEGenc.

This stutter I'm talking about is in the avi when first viewed on the computer; it doesn't just appear in the encoding to mpg. So I'm thinking mats.hogberg is probably on target with the idea of PAL/NTSC conversion being bad at some point. That's what the avi looks like, as though the frame rate got screwed up and the video must hesitate slightly in intervals to keep the timing correct.

And yes, such an avi will look like this on all my computers. It's in the avi itself. I don't encounter them very often, but when I do it's frustrating.

What guns1inger is talking about above seems to have happened with whomever created the avi. Once that's happened, is there any way I can get those extra frames out, or am I just stuck with the stutter?

[guns1inger]

If the duplicate frames are in a regular pattern then you might be able to use an avisynth script to get rid of them. I have seen scripts like this posted here before, but it is beyond my humble scripting skills at this stage.

[Capt.Video]

You never stated what encoder your using. I know with TMPGEnc for example, if the source is A field first and I dont specity if in the encoder, the resulting MPEG will have studders.

GSpot the source, and see if your encoder has options to adjust field order.

Good luck,
Andrew