What resolution and framerate to use?

September 16, 2005 12:12 PM

Video question: I'm working on some homebrewed video animation pieces on my mac. Basically, using matlab to output a stack of images that I then use Quicktime to turn into a movie. The final product of which will be burnt onto a DVD using iMovie and iDVD. Question: what resolution and framerate shoud I be outputting to prevent these apps from having to resample my movie, in either space or time?

I'm guessing that TV resolution is something like 600*800 and quicktime has 29.97 as a framerate option, which is such a strange numbe rthat it has to be right. Am I on the right track?

posted by garethspor to computers & internet (7 comments total)

Close. You'll find good info about exact specs at videohelp.com - NTSC video should be 720x480 pixels (for iMovie/iDVD).
posted by hamfisted at 12:32 PM on September 16, 2005

Oh, and try to output as dv for the format - that should also help keep the video from resampling.
posted by hamfisted at 12:39 PM on September 16, 2005

Since hamfisted has provided a pretty clear answer, I'll add this for interest's sake:

the NTSC frame rate was originally 30 frames per second (60hz interlaced) to match the North American A/C power frequency. When they added colour, they switched to 29.97 to avoid standing interference patterns in the colour signal. I just learned this.

I'm curious what kind of images you're generating. I've never thought of Matlab as an animation tool!
posted by Popular Ethics at 1:42 PM on September 16, 2005

thanks guys! i got it: 720x480pixels x29.97 frames/sec.

popular ethics: matlab is slow as all hell but really simple to program in and has a bunch of math stuff that i wouldn't want to program myself. I'm working on a music video for the brian eno song 'spider and i', the last track off of 'before and after science' there's gonna be a mutating spider web based on voronoi diagrams and an image of the international space station. this is sort of a personal art project to go along with a painting i did. i just like doing my animations with matlab so that i know i have complete control over every pixel of every frame.
posted by garethspor at 3:11 PM on September 16, 2005

Fantastic! I just finished a project where we voronoi diagrams to find the center of a measured circle (technically the minimum width annulus). Good luck, and I hope you post the results to your site.
posted by Popular Ethics at 4:01 PM on September 16, 2005

If this is silent animation, 30 fps should be just fine. The issue with 30 vs. 29.97 is that if your video has sound, the sound will start to noticeably desync after a few minutes.
posted by neckro23 at 9:08 PM on September 16, 2005

720x480, 30fps (it won't matter about the 29.97)

Either do an image sequence or render into the NTSC/DV codec, as that's what iDVD handles (per video) best+fastest. Uncompressed would cleanest...but iDVD is optimized for a DV workflow.
posted by filmgeek at 12:26 AM on September 17, 2005