Sorry - just a bit rusty on interlaced AND haven't shot any for over 10 years!  Wondering how Avid handles it internally? My workflow for broadcast has generally been work in progressive from progressive media, full render, switch to interlaced, pop on a legalizer and export AS11.  I've always taken it that the legalizer render effectively gives Avid a chance to make everything interlaced (even though the fields will be identical). Where I get actual interlaced media in to include in my progressive edit I always remove any modifiers Avid auto puts on it as its better that it wil be proper interlaced for output (no need to de-interlace it and then re-interlace it). TV channels work solidly in interlaced so this issue doesn't really crop up when i'm there - you work in what you are told!  Any internal workings/better workflow explanations most welcome :-)

You may need to check the technical requirements to find out if it's acceptable to use all progressive material in your edit and just switch to interlaced for output.

For example, the UK BBC specs have the following....

'HD programmes may be originated with either interlaced or progressive scan' 

but...

'HD and SD projects must be set to export progressively shot material as interlaced. Electronically
generated moving graphics and effects (such as rollers, DVE moves, wipes, fades and dissolves)
must be generated and added as interlaced to prevent unacceptable judder.' 

So, although it's fine to shoot progressive, you have to have any effects as interlaced. This would include rollers and any graphics/VFX that were created externally.

UHD programme requirements are somewhat different.

Thanks Bruno .  We all switch to interlaced for rollers or crawlers I'm sure (drives me crazy watching these judder at home when not done)!  However I cant say I request 3d party animated graphics as interlaced renders. Linking to this would pop a temporal effect in my progressive timeline of course to make it progressive.  Will Avid auto remove it if its rendered under other layer when I switch to interlaced?  Still trying to see how it thinks...

As long as you render everything after the project is set to interlaced you should be fine. 

I'd take care not to push for some interlaced content if the bulk of the content is progressive.

Cutting between interlaced and progressive is visually objectionable and would trigger QC issues. Interlaced for fades effects and titles looks better than progressive often does. 

 

 

Thanks Pat.  I think the finishing is quite manual and needs due diligence on sources to overide Avid temporal modifiers a lot to maintain the best final output.  I think I conclude that I WILL render anything progressive in a progressive project but will not allow render of interlaced clips in a progressive project - ahh but then that cross fade from P clip to i clip ?!!!  Remove all renders I guess and switch to i - nasty on a multi layered heavy render project...

EDIT:  I see others answered basically as I did while I was typing!!!

That is a pretty solid workflow.  But I have one sort of big difference.  And it follows my "Start at the end and work backwards" mantra.

If I know I am going to only deliver Interlace, I work in an Interlace sequence IF the sources are the same frame rate as the deliverable.   The exception is when I am working on a project that I know needs a Progressive deliverable (for the web) as well as a Interlace deliverable.  In that case my sequences will be Progressive.

The reason for an Interlace master sequence is effects processing.  In an Interlace sequence a DVE push in will be process in fields and will look smoother than on processed in a Progressive sequence where the push is process in frames.

Jef