Interlace problem after using event pan/crop

Warren Hedges wrote on 4/18/2008, 4:52 AM

Has anyone else had interlacing problems (field inversion/reversal [flickering video] after using event pan/crop to zoom in or out of a video clip?

We shoot on XDCAM @ IMX50 and bring footage into Vegas via FTP. When the project is finished it is rendered back to MXF IMX50 and imported into a Pinnacle Liquid Silver to render to tape (SP BETA).
When no effects are applied in Vegas, everything works as expected. However if an event has pan/crop effect applied to it (such as zooming in on the video a bit) when it is rendered out to MXF(IMX50) the resultant clip will have the fields reversed/inverted (flickering video) on that event that had the pan/crop applied to it.

Applying "Reduce Interlace Flicker" to the clip does help a bit but the resultant clip does not appear as sharp as the original.

Has anyone come across this sort of problem before? Are there any quick fixes?

thanks
Warren

Comments

rs170a wrote on 4/18/2008, 5:02 AM

Shift your Pan/Crop up or down one line and that should take care of your problems.

Mike

Warren Hedges wrote on 4/18/2008, 5:50 AM

Thanks Mike.

Is there an easy way to determine if we are on the correct line before we render the project off?

Thanks
Warren

DJPadre wrote on 4/18/2008, 6:02 AM

make sure your interlaced output is configured to corespond with the appropriate field order.

If you start with 1920x1080, make sure that your pan and crop zoom is also at an even number.
Vegas also flakes out when u try to pan and crop a slowmotion clip...
For some reason, Vegas is yet to have the ability to handle messed up field orders

Laurence wrote on 4/18/2008, 6:31 AM

Make sure you have a deinterlace method selected. It doesn't matter whether it is blend fields or interpolate because you won't actually be deinterlacing.

For some reason, during pan/crops Vegas resizes footage differently based upon whether or not a deinterlace method is selected. If a deinterlace method is not selected, it resizes the whole frame at once like you would expect it to do for progressive footage. This looks terrible however on interlaced footage because the interlace combs get resized and after the resize have nothing whatsoever to do with to odd even fields of the new interlaced size.

If you select a deinterlace method however, Vegas will separate the odd and even fields, resize them separately, then refold them back together into a new properly interlaced resized image. This looks a whole lot better obviously.

If you are having issues with field order reversal, just zoom into half resolution on your pan/crop screen. That way all your adjustments will take place two lines at a time since the half resolution zoom drops every second line in your workspace.