Question about deinterlacing

[Steven Gotz]

I have a 720 HDTV. My customers all have 720 HDTVs. Even though I shoot 1080i, I often export to WM9 at 1280X720 because there is no need to waste data rate on something bigger.

I have found that it makes sense to use Premiere Pro 2.0 to deinterlace by right-clicking on the clips in the sequence and setting the frame options to "Always Deinterlace".

Now, I know I can deinterlace upon export to WM9, but it seems to look better if I do it on the sequence.

Am I fooling myself? Does anyone or everyone agree that deinterlacing on the sequence looks better? Is it because it is deinterlaced at 1080 and then scaled down so that the quality loss is not as apparent? Does the Adobe Media Encoder deinterlace after the scaling?

Does the fact that I am using Aspect HD 4.0 make any difference at all in this issue?

Anyone know for sure? Anyone have opinions on the subject?

[Peter Jefferson]

one things for sure is that your NOT losing all that much resolution.. PP2 has had some major rehauils of its engines, its a pity the RTX2 DOESNT support 720p though.. now THATS a bummer..

either way.. even if u encode to 720p, it "should" look better than the 1080i in theory.. as in effect, your running a higher resolution per frame burst.. theres alot of arguemtn and discussion about this, but in the end, there are many deinterlacing tools available.. the most prominant being After effects...

"I have found that it makes sense to use Premiere Pro 2.0 to deinterlace by right-clicking on the clips in the sequence and setting the frame options to "Always Deinterlace". "
Its time liek this when PP2 needs scripting.. From memory though i DO believe PP2 allows u to set your project settings on a project level BEFORE you begin so u can set it up to 720p, then import your footage to THAT timeline and then export your timeline as 720 from there.. it SHOULD save u from having to go through EVERY clip... that would be VERY tedious indeed.. then again, many adobe tools do have tedium plastered all over them, even though thyre powerful, some of the most basic needs are a headache to set up..

[Steven Gotz]

Well, actually it is a hassle. But I used a contact at Adobe to attempt to get the Adobe Media Encoder guys to give me an answer. Does it scale then deinterlace, or deinterlace then scale. If it does deinterlace first, then that is the easy way. Just use the encoder to do the job.

I would love to have Cineform's opinion on the subject. What is the best output method? On the sequence, or in the encoder?

[David Newman]

Steve,

I don't know if one method is better than the other, however Premiere should always deinterlace before scaling, otherwise you get a weird ripple in the image.

[Richard Leadbetter]

What sort of deinterlacing technique does Premiere use? A simple interpolation of the fields? A 'smart' bob that only deinterlaces where the fields do not mesh?

[Steven Gotz]

I have put in a request to get more info from Adobe. I will let everyone know if an answer is made available.

[Pete Bauer]

Steve,
I'm sorry that I don't know what tech that PPro 2 is using, but I agree that it does a great job on the timeline. I've been pleasantly surprised with how good 1080i60 taken down to a 1080p24 for 40% slo mo looks. I'd assumed I'd have to use AE for that, but the render straight off the PPro timeline satisfied my eye. Even if I don't know how it works, I'm happy using it!

[Joshua Provost]

Originally Posted by David Newman

I don't know if one method is better than the other, however Premiere should always deinterlace before scaling, otherwise you get a weird ripple in the image.

Not necessarily. For instance, you can scale an interlaced clip in an interlaced timeline, and it remains interlaced, with no ill effects from the scaling. That is because it is scaling on a field basis. The lower fields as a group are scaled and the result put back in the lower fields, while the uppers are scaled and put back in the upper fields. No weird effects.

So, it is important to understand what the sequence is, because it may be doing a field-based scale and then deinterlace the result, which would perhaps not be optimal, but you wouldn't see majorly weird interlacing-related effects. Regardless, since this is downscaling you're talking about, it's hard to screw up. Upscaling is another story.

[Jeff Baker]

So wait, I don't have to use Magic Bullet or RE:Vision's Deinterlacer anymore? That is what I always used on my DV 30i footage not trusting Premier to do it.

It would be nice NOT to have run those plugins on HDV since at current cpu speeds it would be very very slow to render.

[Joshua Provost]

Has Premiere's deinterlace engine really changed significantly in 2.0? Because it was absolutely dismal in all previous version. Regardless, it'll only take your 60i to 30p, it won't convert you to 24p.

[Alex Raskin]

Originally Posted by Steven Gotz

I have found that it makes sense to use Premiere Pro 2.0 to deinterlace...Now, I know I can deinterlace upon export to WM9, but it seems to look better if I do it on the sequence. Am I fooling myself?

Make another PPro project in 720p.

Import both videos - one made with PPro deinterlacing before editing, the other deinterlaced on WMV output.

Put them on the timeline above each other, in sync.

Now simply switch the visibility of top one off and see if there's any difference in quality.

Go through different scenes (light/dark, static/movement, etc.) to see how the difference changes, if at all.

Then tell us :))

[Jeff Baker]

When I try to open adobe media encoder from within Prem Pro 2.0, it takes about 60 seconds before the exporter opens when working HDV footage.

Is this typical? I thought my system had froze.

[Steven Gotz]

I get about 15 seconds now and then for a long timeline. So I suppose 60 seconds is plausible if the project is complicated enough.

[David Newman]

That all the Adobe Media Encoder, we have no control over that.