Combing effects going from 1080i to DV-PAL

[Aaron Star]

Some screen shots of your project settings, and media info on your source media would help.

Try a new blank project, and drag and drop one source clip to the timeline. Then see if you still have the artifact problems.

[Eric Clinch]

Try using Interpolation as the Deinterlace method not Blend fields.

[László Kovács]

Do you see that combing effect on preview only, or in the rendered video?
If you rightclick an event on your timeline, properties show progressive (wrong), or upper field first?
Sometimes Vegas detects P/I incorrectly – in my case a 25p footage from Canon xa10 is detected as interlaced – however it is progressive. I have to set it manually to P.
Your case may be the opposite, an I detected as P. Set the interlaced flag manually if it is wrongly P.

Best regards

László Kovács

[László Kovács]

Oh, it’s too early in the morning… ☺
I forgot to mention: if you see that combing on the preview only, be aware of that preview is just preview with different quality steps.
In “preview” and “draft” no deinterlacing is done, if you set the quality to “good”, the deinterlaceing will be done for you – at a cost of more processing power required for the preview.

Best regards

László Kovács

[Paul Strickland]

Thanks for this. It’s early here too….

I’ve been playing with this over the last hour, and I’d started to come to the same conclusions.

The combing problem definitely occurs on both preview AND the rendered output. In fact, it was only the client looking at a sample of the render on his own DVD player that spotted the problem, I’d had preview set to a lower quality and hadn’t seen the problem in any of my usual checks.

Just running some tests and the only way I can lose the problem (in auto quality preview at least) is to set the field priority to Progressive. So maybe it’s a similar problem to the one you had. I’ll keep playing…..

[Paul Strickland]

Er no. Forcing the source video to progressive make the problem worse. Different, but much much worse

This is a snip of the original problem, file played with VLC. Fine combing lines.

After manually forcing the source to Prog scan, the combing becomes softer, but much more pronounced.

Help!

[Paul Strickland]

Now I’ve worked out how to get images onto posts, here are the requested setiings…

[László Kovács]

Hi,

I meant the opposite: force the source interlaced if it is wrongly detected as progressive.
If you force the source to be progressive, however it is interlaced, you basically switch off Vegas builtin deinterlace.
What you see on your second sample is the moire of the 2 interlace combs – as your target is interlaced too.
The first picture you posted here seems to me correct – as it is interlaced.
This combing is there by design – this has to be deinterlaced during playback.
If you play at this file (DVD) through an old CRT TV, the deinterlacing will be done in your eyes/brain.
If you play it on a DVD attached to an LCD (or similar tech TV), the deinterlacing has to be done in the TV set.
If you play it on a computer, the player software has to deinterlace it.
(All of my sentences are meant with “- I think” at the end ☺ )
You can however put progressive content on a regular DVD, this is what I do for the last few years, as I always deal with progressive source.
For this, set you project to progressive, and render to progressive.
Here are my settings for such a “progressive” DVD:

Note, that if you create a DVD this way, it’s motion will look a bit more stuttery on old CRT TV’s compared to the interlaced DVD (as the picture is now 25p instead of 50i).

Best regards

László Kovács

[László Kovács]

I was writing my reply while you posted your settings.
I think these settings are correct if you finally need an interlaced DVD…
For the rest see my previous response ☺

Best regards

László Kovács