Hi, I'm using FCPX 10.4.6 with macOS 10.13.6 with all current updates.
I know that you can select "Deinterlace" in a clip's "Settings" and that will deinterlace an interlaced clip by doubling the frame rate (fields become frames, but the manual and Apple website mention nothing about how the frames are constructed, i.e., how missing lines in fields are constructed). You can apply this setting to clips in the Browser as well as those in Projects.
However, it seems that whatever a Project is set to, say either "29.97i" or "29.97p", that this setting overrides whether a clip added to a Project remains interlaced or deinterlaced.
So, adding a progressive clip to a "29.97i" Project will result in that clip automatically being interlaced. The opposite occurs, as well. I couldn't find any mention of this behavior in Apple docs or website.
Note: I don't particularly want FCPX to deinterlace my footage for me, as it does so in what seems to be a fairly "crude" manner, either using the "fields to frames" (Deinterlace setting checked) or some other manner once a clip is in a progressive Project.
What I am trying to do is use Revision Effects' FieldsKit for deinterlacing (as an Effect in FCPX). I've asked their support for help but it hasn't proved fruitful yet.
My thoughts are that I should use an interlaced Project ("29.97i") and add the unaltered interlaced clip to it. Then, apply the FieldsKit deinterlacing plugin and either create a compound clip or export the clip in the Project to a master file and re-import it.
With a little trial and error, and some further help from RE:Vision Effects, I may have figured out some things...
First, in order for things to work well, and changes to be visible, you need to set the Viewer to show both fields, the Viewer must be set to 100% and at Better Quality.
Second, a progressive Project should be used.
Either before (in the Browser) or after (in the Project timeline) the clip is added to a Project, its clip settings should be set so that the "Field Dominance Override" is "Progressive" and "Deinterlace" is unchecked.
The clip will then display its fields in the Viewer.
In my case, I can then add "FieldsKit" as an effect and adjust the settings until the result is acceptable.
I hope this info proves helpful to others.
P.S. - So, what all of these steps do is prevent the FCPX Project from "auto-conforming" the added clip to its settings.
Some of you might find it informative (others, trivial) to know more about the context of my initial query...
I've been tasked with using some old, originally 8mm film in a documentary project. Nothing new about that. The original film was projected and recorded in interlaced format by a video camera by one of the "save your memories" consumer-oriented facilities (rather than being digitally scanned). 8mm film from the late 1930s and early 1940s was usually shot at 16 to 18 frames per second.
Some of the video clips I received were on DVD (DVD-Video, not files) and some were DV-25 files. Unfortunately, both sources were interlaced, standard definition 29.97i video. The original sources aren't available, or have degraded beyond use. When the source material was transferred to video it was in decent to poor condition.
So, part of my workflow involves trying to clean up the video and make some rudimentary image adjustments to see what's usable. Deinterlacing is an important step in the process, as it helps to remove fields and reduce/eliminate duplicates in the resulting frames, both of which are necessary for successful denoising (mostly temporal, "inter-frame" noise).
Since most denoising tools that remove "dirt", etc., rely on successive frames being different as much as possible, deinterlacing drastically improves the quality of results possible. Deinterlacing also helps make "deflickering" more effective, too.
If you use FCPX's "Deinterlace" clip setting, or let a progressive Project auto-deinterlace a clip, then it's likely that subsequent use of any number of temporal denoising tools won't work very well, if at all...
Even if the film is decrepit there's an excellent chance it can be recovered. My specialty here is not only transferring film into high def 1080 ProRes files but also recovery of film that's deteriorating. Sample of 8mm film frame (1958) and reconditioning outcome of 16mm film (1946) that's gone bad.
Thank you for your detailed posts. Although most people don't have to deal with interlaced source footage anymore (fortunately), this information is very helpful.
It is correct that any auto-conforming of interlaced footage in a progressive timeline will lead to loss of resolution due to the basic method that is being used (line doubling). If you don't need to do anything else to the video, this may be acceptable.
But when you need the best possible deinterlaced quality for further processing, your method is perfect. Setting Field Dominance to Progressive in a progressive timeline will make every field available for proper deinterlacing using advanced tools such as Fieldskit, which give you far better deinterlacing options and even motion estimation. The resulting "progressive" footage will be more solid for further processing.