Yes, as Marco says, no need to deinterlace if your goal is an interlaced Bluray

Hi Marco, thank you for replying. My source in interlaced. The reason I use deinterlace is because there are several sequences on my timeline where I have used track motion to zoom in or adjust the orientation of the frame. If I render with deinterlace disabled, all these adjusted sequences in the output get a combing effect while the rest of the video turns out fine. It's not a media player or BD player issue not deinterlacing properly, believe me I've tried everything. There's probably a logical reason that explains this but I've stopped trying to understand it after so many attempts. Of course, I was not satisfied with rendering the entire video with deinterlacing enabled because of the visible loss in the output quality, so I've resulted in rendering each adjusted sequences as uncompressed files, with deinterlace enabled (Interpolate Fields or Blends fields, depending on the sequence). Then I dropped those uncompressed sequences in my project timeline and render the whole video with deinterlace set to none. This resulted in an output where most of the video looks as good as it can, with only those adjusted sequences looking not as good.

I've since made to jump to Vegas Pro 15 and Smart adaptive deinterlace is said to do a much better job than the previous Sony deinterlace filters. I still only want to use it where's it's needed by rendering the adjusted sequences independently, but instead of rendering them uncompressed and dropping them on my timeline and render the final output, I figured I'd render them in the same blu-ray AVC template as the rest of the video (except with smart adaptive deinterlace enabled), and merge all of the output AVC files in a muxer like VideoRedo or tsMuxer.

If you have a better idea of going about this I'm all ears. I've tried to render as progessive but it doesn't turn out well. I still get the combing effect on those sequences and the quality of the output is not very good. The source footage is from an older Sony HD camcorder that only outputed interlaced AVCHD files (m2ts). I've since upgraded to a progressive camera and don't have to deal with this problem.

Thank you.

That is because you do not have BEST selected as rendering quality. With this option selected, image repositioning and enlarging is handled correctly.

Hi David, Yes the render quality is set to Best.

Then something else is wrong. I repo and zoom a lot and never have this issue unless it is set for GOOD and not BEST. You are killing the quality with deinterlacing. Please show a screenshot like the one I posted showing it set to BEST. (if you don't mind humoring me. 😀

Ah, I think there actually it is needed to use one of the project's Deinterlace Methods when changing the frame sizes of interlaced footage. While it does not mean the signal would be deinterlaced in the end, it just determines how the field handling will be done e.g. for resizing. But I can't go deeper into it tonight.

These are the project properties with deinterlacing set to none. as you can see Best is selected.

Okay, only other suggestion I have is to enable the Deinterlace Method. I use interpolate. Something rings a bell about that being used when repo and resizing but can't swear to it. Good luck.

Ok, so coming back to the original question: Does smart adaptive deinterlacing only work with NV encode?

Ok, so coming back to the original question: Does smart adaptive deinterlacing only work with NV encode?

Smart adaptive deinterlacing works for me as long as I have GPU acceleration of video processing set to my GPU (AMD). I just did a render of AVCHD 1080-29.97i to MainConcept 1080-29.97p and it made a very nice job. If I don't have GPU acceleration on then smart adaptive deinterlacing does not work and I see stair-stepping.

I'm guessing that by "NV encode" you mean NVENC. And I'm guessing "CQP" is a constant quality parameter that becomes available if you have an NVENC-supporting GPU (which I don't). But the direct answer to your question in isolation is "No".

I just tested again and in general I can just confirm what Nick said. »Smart Deinterlace« should work fine if GPU acceleration is turned on in »Options/Preferences/Video« and if there's no special issue with the grafic device because »Smart Deinterlace« is a GPU based process.
And whichever Deinterlace Method is selected in Project Properties, when it is about scaling it is a process which happens before the export render process so for scaling there should be no difference which codec you take for your output.

Also I re-tested scaling of interlaced footage and it's just as I thought:
It is critical to have one of the Deinterlace Methods selected in Project Properties else you would also scale the interlace lines of your video. Selecting Deinterlace Method »None« is a no-go for interlaced footage for each kind of internal processing which uses scaling!

Nevertheless – if you encounter problems with »Smart Deinterlace« for your scaling processes I would just select »Blend Fields« or »Interpolate Fields« (and if it is about scaling only, not deinterlacing, then it doesn't matter which of the two you select).

Marco. wrote on 2/3/2018, 11:42 AM

Ah, I think there actually it is needed to use one of the project's Deinterlace Methods when changing the frame sizes of interlaced footage. 

It absolutely is necessary to select a deinterlace method (doesn't matter which one) and select Best Render when scaling interlaced source. Doesn't mean you have to render progressive though, and you shouldn't for Bluray.

Hi Nick and Marco, thanks a lot for your input, much appreciated. I ran another test using smart adaptive deinterlace with Mainconcept AVC and it worked this time. Not sure why it wouldn't play back before.

I'm guessing that by "NV encode" you mean NVENC. And I'm guessing "CQP" is a constant quality parameter that becomes available if you have an NVENC-supporting GPU (which I don't). But the direct answer to your question in isolation is "No".

Nick, by "NV encoder" I was referring to the encode mode in the rendering properties of the MAGIX AVC/AAC template and CQP is one of the NVENC RC Mode options. It may be that I'm not picking the optimum render settings to get the best quality. I tried the default preset and the high quality preset. Both gave me inferior quality than the Mainconcept AVC encode mode. I could play around more with the settings but I'm happy with Mainconcept AVC.

Thanks guys for confirming that deinterlacing is needed when scaling interlaced footage. You would laugh if you knew how much time I've spent trying to get around this caveat. This is definitely the last interlaced project (and blu-ray for that matter) I ever do!