Jerky motion when DVD is rendered. Strange problem.

[wetkitten]

Hi there.

I am really puzzled by the DVD authoring part, any help is very welcome.

My wife shot a short panning clip of a sand storm in 16:9, with our JVC Everio MG275 camera, which records to HD.
I imported the MPEG-2 file to Vegas 8, alongside other clips taken on different days and time, with the same camera settings (shutter speed).
When rendered and checked with VLC, there is no jerkyness, I can see (and blend) the interlacing which is fine.

When I author it with Sony DVD Architect (PAL, 16:9) there is jerkiness on this scene
When I author it with Cyberlink Powerdirector express (PAL, 16:9) there is jerkiness too.
Now, by mistake, I also authored it with Cyberlink Powerdirector express (PAL, 4:3) and the jerkiness was gone (but the aspect ratio was then wrong).

What is happening?

Reading the previous post about "tailing effect on DVD", I changed the settings of the field order:

1. Lower Field First = jerky
2. Upper Field First = not jerky
3. Progressive = displays interlacing lines

SO it seems I found the solution to my problem: to set Upper Field First. But my understanding is that because the source is DV, I should set the Lower Field First instead, which is no good to me as it introduces the jerkiness.
Some other clips on the DVD have Lower Field First, and are not jerky at all.

Can someone please explain what is happening to me?

PS. I am displaying the resulting DVD on a plasma TV. Whether I turn Progressive scanning on the DVD player or not makes no difference whatsoever.

Thanks in advance for enlightening me.

Kit

PPS. Also, is there a way to ascertain the correct field order BEFORE rendering & burning onto DVD ? Thanks

[guns1inger]

Except that you aren't using a DV camera, and the output is not DV. Mpeg can be either lower or upper, but is most often upper. In your case, the camera records in an upper field first mpeg-2 format. Set your project accordingly. If you are mixing different sources - for instance you have some footage from this camera and some from a mini DV camera - you can set the field order of different clips by right-clicking on the clip and selecting Properties.

[wetkitten]

Thank you guns1inger. You are right.

My older JVC camcorder was DV, this one is not, and checking the original clips with Gspot told me that they were TFF, whereas the settings in Vegas were BFF.

I wrongly assumed that the first clip was fine, because it was playing fine even with the wrong field order, as there was not much motion in it. But subsequent clips with more motion were not fine.

So Vegas was the culprit here, as it was unable to recognise correct field order from the original file (its never my fault ). I am still puzzled with this correct authoring with the wrong aspect ratio, but it does not matter much now, I will be able to author my dvds and take a breather from the wife.

Thanks again.

[guns1inger]

I have had Vegas, from time to time, screw up the field order on projects that were all DV. Not the whole project, but just certain clips would suddenly be recognised as TFF for no reason that I could discern. Changing the properties of the problem clips back to BFF fixed the issue. That was back in version 6. I haven't seen it happen in 7, and I haven't yet moved up to 8.

I suspect Vegas switched the order because you told it the project was BFF. If all the clips come the new camera, set the project to TFF and work with TFF the whole way through the process.