- January 31, 2014 at 5:18 pm
A lot of the work I’ve been doing lately has been taking SD footage and scaling it up to fit the 1920×1080 raster. Dropping an SD 4×3 clip (720×486) into an HD 1920×1080 timeline makes the SD clip 226 scaled and 12.5 distort/aspect ratio. Where does that number (12.5) come from and how can I “do the math” or know what distortion value to use when there’s anamorphic SD footage I need to “up rez”?
I’ve seen -33.33 and -12.5 (and probably others I can’t remember). Sometimes 12.5 doesn’t look right but then 10 doesn’t really either. I’m not really comfortable eyeballing everything. I’ve searched google (and the cow) for answers and haven’t found anything. Maybe there’s not an answer other than eyeballing everything. It’s maddening! Any ideas?
- February 1, 2014 at 5:28 am
Best I can tell is that number comes from dividing the pixel horizontal count (720) by the square pixel equivalent (640). 720/640=1.125 the .125 equating -12.5 somehow. The same hold for a 1440×1080 16:9 format. We know that the 1440 is presented/expanded to fill a 1920×1080 space. 1920/1440=1.3333333333 giving that -33.3 number.
But FCP adds this distortion for you. When you place a 1440×1080 clip in a 1920×1080 timeline, it adds the appropriate distortion.
- February 1, 2014 at 7:01 am
“There aren’t any good, hard-and-fast answers, which you apparently seek. It’s a matter of taste.”
Thanks Dave. That’s helpful. I feel a little insulted, maybe it’s my lack of sleep, but I’m not a moron. The “which you apparently seek” comment is what did it. Not cool.
Here’s some background: decisions have been made that are above my pay grade to take old movies and shows and make them “HD” (ghetto-def). We pillar box some of it (filling top to bottom, sides are matted with a textured pillar box), I’m told to loose the letter box on some of the 4:3 (blowing it up even more) and I’ve even been told to loose the black bars on 2.35:1 John Wayne movies. It looks like ass but as an editor, most of the time I do what I’m told. (I like having a full-time job and I’m currently not interested in returning to the 1099 world.)
So, your explanation of what happens when you resize squares inside of rectangles, and rectangles inside of squares is nothing new to me and wasn’t really helpful. Thanks for trying.
Simply saying there aren’t any good hard and fast answers would have been sufficient.
Bret’s response was the kind of assistance I was hoping for. Thank You Bret.
- February 1, 2014 at 7:03 am
- November 19, 2014 at 12:50 am
I myself ignored the math and did it by sight. Here’s how.
I had an SD 4:3 video in FCP7 that I wanted to convert to 720p HD (1280×720). Why? Because putting SD videos on YouTube looks absolutely horrible — you only get decent quality with 720p or (or higher). So within FCP7, I right-clicked on “Sequence 1” and chose “Settings…” I set FRAME SIZE to “HDTV 720p (16:9).” I then set the PIXEL ASPECT RATIO to SQUARE, which will widened my SD clips. To fix the clips, I manually double-clicked each clip and in the MOTION tab I set the SCALE to 150% (which made the top and bottom go to the 720 pixel height), and then I chose an ASPECT RATIO of 7, which fixed the width perfectly (to my eye, anyway).
Yes, there are black bars on the left and right, but since SD isn’t a 16×9 wide format, such is to be expected and I have zero problem with that. I just wanted the top and bottom to fit perfectly in 720p and at the same time make sure the width of each converted SD clip was proportionally the same as what I started with.
I hope this helps.
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