Are we talking about the options under "De-Interlace Method" ?

If so general consensus is that Interpolate Fields gives better results than Blend Fields. As far as I'm aware the only time this matters is when scaling interlaced footage. As there's no downside if that's not happening, as a default I leave Interpolate selected.

Bob.

Blend and interpolate are both very rudimentary. One blurs motion and the other throws away half the visual information. It will be interesting to see if Vegas 10 has some "smarter" deint / decomb capabilities.

I did some tests for Randy Brown not long ago. Although not all-inclusive, they clearly show the differences between traditional and modified yadif deinterlace methods.
http://vimeo.com/user1440262

That's true IF you're talking about converting from interlaced to progressive. It is not true if you're scaling interlaced as far as I know.

What I'm uncertain of is if anything could be gained by doing a motion vector de-interlace from fields to frames, scale and then re-interlace. There could be something in it but my head hurts thinking about it. On top of that getting too much V res into interlaced footage is not such a good thing.

Bob.

That's true IF you're talking about converting from interlaced to progressive. It is not true if you're scaling interlaced as far as I know.
That seems to be the consensus. Having no indication to the contrary, I agree.

On top of that getting too much V res into interlaced footage is not such a good thing.
Agreed. The sharper the deinterlaced output, the greater the likelihood of objectionable shimmer, herringbone, or zebra teeth from interlace artifacts. It clearly shows worst in the sharpest example I posted (handbrake w / decomb). Although others preferred that render, I actually liked the full yadif version better because it is a bit smoother.

The "interpolate" deinterlace in Vegas (which I didn't upload) was by far the worst artifacting.


What I'm uncertain of is if anything could be gained by doing a motion vector de-interlace from fields to frames, scale and then re-interlace.
Interesting topic for some tests. Also sounds time consuming. I think the best test would be to see which method(s) hold up best after upscaling and re-interlacing.

My main interest is in producing the best compromise between sharpness and artifacting for progressive web delivery. The reason is that the best player-based deinterlacing is worse than progressive delivery in every instance I have tried.

"It is not true if you're scaling interlaced as far as I know."

Any half decent (or even quarter decent) scaling algorithm would scale the two fields independently anyway. Deinterlacing before scaling would be the worst thing to do in this case.

"Any half decent (or even quarter decent) scaling algorithm would scale the two fields independently anyway."

That's how Vegas handles it as long as you have the "Deinterlace method" set to anything other than "None."

"My main interest is in producing the best compromise between sharpness and artifacting for progressive web delivery."

Deinterlace in Vegas - a foolproof method follows:

1. Download and install Mike Crash's free Smart Deinterlace for Vegas - works with 8x or 9x, 32-bit only.

2. Set Project Properties to 59... frames per second, best rendering quality, interlace set to None, 1920x1080 (presuming that you are starting with 1920x1080i).

3. Use Smart Deinterlace effects on media (go into the media window and right-click, or right-click on the FX button on any event and choose the source file for the Smart Deinterlace). In order to avoid artifacts, you should right-click on the clip, click Properties, then clear the checkmark for Smart Resample.

4. In the Smart Deinterlace FX window, choose “field” preset. In clip properties, set resampling to “none.” Motion Threshold: 5. Choose cubic, and motion denoiser.

5. Or, if you have an entire track on the timeline that has many interlaced clips, you can do them all at once by clicking on the track FX button (stills, progressive clips, etc., on the timeline will be ignored); but there is a trick: You must go down to the bottom of the Smart Deinterlace FX window where it says "Smart Deinterlace" and make sure that the little triangle at the far left points to the left; if pointing to the right, click it once to make it point left. (You won't need to worry about this if you apply Smart Deinterlace to individual clips in the Project Media Window instead of to the track.)

Then render out with Cineform using Progressive setting; or with PicVideo-Progressive. Result: No judder, no comb, no loss of resolution.

Please note that Smart Deinterlace works only in 32-bit versions of Vegas. I always deinterlace any interlaced clips immediately in 9c-32 bit and discard the original, then put the progressive clip on the TL in Vegas 8c (32-bit) for editing. When it comes time to render, I render in 9e-64 bit. . . a two-step from heaven

I wish I could remember who posted this method originally so that I could give credit to that person - here on the forum, I believe . . . I didn't originate it, but it's a life saver for me; maybe should be a sticky

LReavis,
Thanks for going to the extra effort to post this, and I'm certain it will benefit many who want to keep their whole workflow in Vegas. Certainly better than the default deinterlace options.

Actually, I tested the Crash deinterlacer side by side with Handbrake some time ago, and the modified yadif in HB works better for my purposes (and renders faster) -- ymmv.