Personally, interlacing can’t go away fast enough to suit me. Unfortunately, interlacing will be with us for many more years, so we need to learn how to deal with it.
The process of converting an interlaced clip to a progressive clip is called “deinterlacing.”
Interlacing began in the earliest days of television to solve problems related to displaying moving images, and continues today because it reduces the bandwidth necessary to transmit or cablecast HD video.
NOTE: The web always prefers progressive video. However, many cable and broadcast outlets require interlacing, which is why this problem persists.
What interlacing does is divide an image into two “fields,” where all the odd-numbered lines in the image are in Field 1, while all the even-numbered lines are in Field 2. In and of itself, fields are not a bad thing. The problem is that when we shoot an interlaced image, there is a slight time difference between when the two fields are recorded. For stationary images, this isn’t a problem. But, moving objects in the frame develop thin horizontal lines corresponding to the time difference between Field 1 and Field 2.
Here’s an example of interlacing. Notice the thin lines radiating horizontally from the speaker’s moving hand?
NOTE: This is why, whenever you shoot video, always shoot progressive images. It is very easy to convert progressive to interlaced. Converting interlaced to progressive – though FCP X makes it easy – always diminishes image quality.
ADD PROGRESSIVE VIDEO TO AN INTERLACED TIMELINE
Adding a progressive clip to an interlaced timeline is easy. Just edit it in. Final Cut automatically converts it to interlaced and there is no drop in image quality.
NOTE: UHD and 4K images are always progressive.
ADD INTERLACED VIDEO TO A PROGRESSIVE TIMELINE
In either the Browser or the Timeline, select the interlaced clips you want to deinterlace.
Open the Inspector (Cmd + 4) and click the Info text button at the top.
In the lower-left corner, change the popup menu to Settings.
Then, check the Deinterlace checkbox.
NOTE: Selecting the Deinterlace setting causes the frame rate of the selected clips to double. For example, if the original interlaced clips have a frame rate of 29.97 fps, the deinterlaced clips will have a frame rate of 59.94 fps.
VERIFY YOUR CLIPS
As you can see in this screen shot of a moving hand, deinterlaced clips will, most often, appear a bit softer than a progressive image. This is the result of the deinterlacing process.
To verify that the interlace artifacts are gone (i.e. those thin horizontal lines) set the Viewer to 100% view, Better Quality, then press the left or right arrow keys and look at the image in the Viewer.
Depending upon the speed of your system, deinterlaced clips may require rendering.
41 Responses to FCP X: Interlace and Deinterlace← Older Comments
So just spent 6 weeks editing a big job..using edits from my old imac and FCP older version..I exported the projects to the new FCPX 10.4 and new mac..Went to export the final edit and the interlace issue was SHOCKING!! I never had this problem with the same project/clips in the old mac/FCP…Does anyone know the workflow starting with formats to record to on my Canon 5D and then to the new FCP 10.4 to avoid the interlace issues??…any suggestions appreciated as I’m going to lose my mind with it due to the fact I need to hand over the job in 4 days..thanks in advance
Actually, you did have this problem with the old version of FCP 7, however, QuickTime Player 7, by default, never displayed interlacing. It only displayed one field, which made it look like nothing was interlaced, when, in fact, it was. You needed to change an internal setting to display interlacing. Quicktime Player X defaults to showing interlacing. The problem was there, all the time.
You can solve this issue two ways:
* Edit and export your interlaced footage as normal. Then, use Compressor to deinterlace. Here’s an article that explains how: https://larryjordan.com/articles/compressor-how-to-deinterlace-video/
* Or, you can select all the clips in the timeline, go to Inspector > Info, open the Settings menu and check “Deinterlace.” This will deinterlace all clips in the Timeline at once.
My general preference is to deinterlace during compression, but try both and see which one works the best.
First off, thank you so much for this post!
I’m having a problem getting horizontal lines (which I assume is an interlace issue) off some older footage that I imported into FCP 10.4. The footage is SD 720 x 480 from a canon xl1. I’ve tried checking the ‘Deinterlace’ box under Info, but it doesn’t change a thing to the footage.
You mentioned that “the project also needs to be set to deinterlace,” but I can’t find anywhere to set the project to deinterlace.. not sure what I’m missing here, but it’s driving me nuts.
Any help is much appreciated!! Thank you again for posting such great content.
I’ve found it best to import and edit interlaced footage as interlaced. Export a master file that’s also interlaced. This way, you have the highest quality image possible edited and saved for the future.
Then, remove interlacing during the compression stage. Compressor is good for this, as is Adobe Media Encoder and other compression applications.
Can anyone tell me where the deinterlace option is located in FCP X 10.4? Still trying to find things with the new menu layout!
Deinterlacing happens automatically when you drop an interlaced clip into a progressive project.
If you need to preserve interlacing, make sure the project, itself, is interlaced. For example, a 1080i project is interlaced. A 1080p project is progressive.
“Deinterlacing happens automatically when you drop an interlaced clip into a progressive project.”
This is exactly opposite of what you said in the body of the article!
Hi Larry ! Your articles have been a great help – exporting from FCP x for a Singapore Boradcaster and they need the master in an interlaced format. I’ve followed your instructions and changed the project timeline to interlaced so that should help. So in the Inspector – for the Field Dominance Override – I’ve selected ‘off’. Hope that shouldn’t be an issue? Pl. let me know, Thank you !
This should be fine – but running a quick test to make sure is always a good idea. Deliver a sample video to your broadcaster ahead of deadline and make sure it meets their specs.
SD is lower-field dominant. HD is upper-field dominant.
Hello Larry, just to bring some more light here, you stated that “SD is lower-field dominant. HD is upper-field dominant”. That is unfortunately NOT true from my point of view, and needs some corrections/additions at this point.
All SD formats are actually upper field first, at least in Europe. I don’t know about NTSC, but I’d love you to tell me. That means all analog formats (BVU, Betacam, VHS, betamax, etc…) are ALL upper field first. Even the digital formats, like D1 or DigiBeta, are all upper field first. The only exception I’m aware of is a very specific format that is DV. This one has been engineered for not real reason as such, and when you transfer data between tape and computer, you keep this lower field structure. But if you decide to digitize your tape with a regular VCR, thru its SD video output, then your dominance will be the one of your video board, that is in general upper. That means that a DV thru firewire will stays lower, but a DV digitized with regular board will become upper…
Thanks for writing. I’m always happy to learn more.
I’m editing sd footage that I’ve had to un-squeeze and add a new letterbox to. When I render and then play the footage the letterbox on top and bottom are moving a bit (up and down-ish). I’m guessing this is a field issue maybe? I’ve checked the Deinterlace box and that gets rid of the letterbox movement. As a result, the footage looks interlaced, even though I checked Deinterlace.
I’ve also unchecked Deinterlace and unchecked the Color wheels or White balance. This too will get rid of the letterbox movement, but then I lose white balance and/or color wheel effects.
Any ideas on how I can fix this? I’m hoping to keep white balance, color wheels, and it be deinterlaced all without the letterbox moving.
I know you’re very busy and I greatly appreciate your time and efforts.
Hmm… I’m really surprised the letterbox is moving.
Only check Deinterlace if you are editing interlaced footage. Otherwise, leave this alone.
* Select all your clips
* Choose File > New > Compound clip
* Apply the letterbox / crop settings to the compound clip.
see if that works.
Thank you so much for your articles. When I add a progressive clip to an interlaced timeline the Final Cut do converts it to interlaced, as you said. However, in order to do that, Final Cut duplicates some frames and the television channels does not accept files with duplicated frames. Do you know any other way to convert progressive clips to interlaced without the duplicating issue?
I don’t think FCP is duplicating FRAMES, that would screw up the timing of all of your edits.
It may be duplicating FIELDS, however. Check with your distributor to see if they have a recommended software tool or service provider who can handle this conversion for you.