Creating an SD 4:3 Center Cut from HD 16:9 Footage

Posted on by Larry

[ This article was first published in the August, 2009, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe. ]


Eric Mittan, from WSIL-TV, writes:

If I have footage shot by the new JVC HM700 (720p60 – we’re an ABC affiliate) and I need to do a center cut of the footage to get it into a 4:3 format, what exact scale number should the footage be set to in the Motion tab of Final Cut Pro to have the footage fill the screen exactly? My Sequence preset is NTSC-DV. I can eyeball it, but I’d rather have an exact number, and I don’t know a formula to figure it out.

 

The situation: I’m in a newsroom at a television station and our production switcher is not yet HD, and likely won’t be for a few years. However, the mandate came down from management (and I agree) that there should be no more standard definition cameras purchased by news or any other department. When one of our DVCAM cameras went bad, we ordered an HM700, which we love, but it only shoots 16:9. We can only broadcast 4:3 footage out of our news switcher. We cannot letterbox the footage, as most fullscreen graphics coming from the graphics department will still be 4:3 format, and I’ve been told to find a solution that does NOT have us switching back and forth between letterbox and 4:3 content within the same package (they also weren’t too keen on moving back and forth across the whole newscast in general.) The solution is that anything shot with this camera will be still be cut in FCP just like all our other footage, but it must be blown up to fill the screen and crop off the sides.

Larry replies: Eric, thanks for writing. I got my start in TV news, so I always have a soft spot in my heart for the folks in the newsroom.

I loaded a 720p clip into the Timeline and starting playing. After fiddling, I discovered that if I set Motion tab > Scale to 100%, it was a perfect center cut. However, this number will be different for 1080i footage.

Try this and let me know what you discover – I’ll add this to the next newsletter and see if people smarter than me know a better way to do this.

Also, be sure to set your render files to ProRes – up to 40% faster render times. Sequence > Settings > Render Settings (you can also set this in System Preferences).

Eric then wrote back:

Thanks for all your help! When I put the footage in a timeline, the perfect scale seems to be about 74.5% to do a center cut. I’ll probably round to 75% as our standard. But I just found out I’m meeting with Keith Tomiser from JVC today, so if he has a specific answer, I’ll pass on the knowledge!

 

I did some tests on rendering formats, and I think in a true production environment, you’re likely right. We’ve got a few mitigating circumstances, though. First and foremost being that as a newsroom, we simply don’t do that much rendering. Our longest pieces are 2 minutes, and they are mostly straight cuts with a few crossfades. The second being that because of our short-form content and quick turnaround, editors themselves are NOT responsible for cleaning out capture scratch and render scratch themselves after an edit. As Chief Editor and Mac Specialist, that falls to me, and I get to it about once a week. With render set to DV (the same as our output) I don’t feel like we loose any quality on our output, and I don’t have issues with hard drives filling up.

Larry replies: Thanks!

UPDATE – Aug. 31, 2009

Eric Mittan, adds this update to his comments:

A quick follow up to our discussion of center-cutting HD footage to SD footage included in this month’s newsletter:

 

Our ultimate solution was to go ahead and edit in an HD timeline. Our footage is all shot at the 19Mbps setting for 720p60 on the HM700, soI’ve simply told our photographers and editors to start with a fresh timeline, and answer yes when Final Cut asks if you’d like to match the sequence to the footage. Then we export at the same format. The final step before being sent to our playout server (which only takes Standard Def DV) is to drop the finished quicktime onto a Compressor droplet set to center cut the footage and convert from HDV to DV. It means less rendering during editing (since our footage matches our timeline) and if need be, the droplet can be set so that the destination automatically sends the file to our playout server. It eliminates a lot of steps.

 

It also means that even if we intercut between standard def and high def, while the SD footage is pillar-boxed in the timeline, the black pillars are cut off in the droplet, resulting in a delieverable that manages to keep the same 4:3 aspect ratio the whole time.

 

The Compressor droplet then can also be used to convert raw footage to DV to be cut on our edit bays that are still running Final Cut 5 and do not support footage from the HM700. (a temporary step – we’ll be upgrading all editors running FCP 5 to FCP 7 sometime before the end of the year.)

Larry replies: Thanks for the follow-up.


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