In previous versions for interlaced media our workflow for TV studio type content was to have interlaced Hi res media DNX120 50i and then switch to a progressive project and trancode to Dnx36.. So although Dnx36 is only Progrssive in fact the image retained the interlaced content so it still looked interlaced 

 

In 2021.12 the dnxLB has one field duplicated os no longer retains the interlaced look once transcoded.

we can see a work around for this.. Ultimately what we want is DnxLB interlaced as a look even if not as a format..

 

Any thoughts?

I'm not sure about that an interlaced format has 50 updates per second. In progressive you would need to be 50p to achieve the same look.

You can't make 50i look the same in 25P

Is the issue that previously the 2 fields were deinterlacedinyo to dnx36 P frame and with DNxLBit just duplicates field 1? 

nigelgourley:

dnxLB has one field duplicated

Just to make sure, you're still talking DNxHD-LB, not DNxHR-LB, right?

As a workaround, what happens if you open your 50i source clips in their bin, choose to display the Field Motion column and set that to Progressive, prior to transcoding? This could possibly prevent MC doing any deinterlacing. After transcoding, you might even switch that back to Interlaced, I guess, but as long as you're playing back ina 50i project and feeding the monitor 50i video, that should be a moot point, in theory.

Pat Horridge:

I'm not sure about that an interlaced format has 50 updates per second

If the footage was capured as 50i, then it would, of course. Field step through 50i footage and you can tell there's 50 motion steps/sec.

Pat Horridge:

You can't make 50i look the same in 25P

Sort of. Both 50i and 25p store the same amount of lines/pixels, and play back the same amount of lines/pixels. So if you tell MC the source is progressive, little else happens than MC storing both rasters in a single frame container, and as long as you're outputting as 50i to your monitor, you would end up seeing 50i, since the monitor is receiving the entire frame split into two rasters (which it originally was).

Similarly, 25p film scans on 50i videotape relied on the same idea, in that each frame was split into two rasters (with identical field motion), Avid would capture the 50i signal and mark it as progressive, and when it played back to a regular SD monitor, MC would split each frame back into two rasters (in a 50i) signal, which the monitor would then display. Obviously, in that case, the Field Motion would still be 25Hz.