beginner 24p Capture questions

B

Barry Landis

Member
My big tangled ball of questions is something like....Is 24p automatically captured in Sony Vegas if that's what's on the mini DV? The Sony Vegas "help" files doesn't mention anything special about capturing 24p. There is a 24.00 setting under "custom frame rate" in the Sony Video Capture software..Is that it for capture? Or is that necessary even? Do the other 24p settings in the software effect how it's captured? Do I ever have to worry about the computer de-interlacing video that is already progressive? A friend captured a bunch of 24 into AVIs with Pennacle.....did it get the 24p ya think? IF SO...if that's it, then are those files 24p and will play as 24p? Any insignt would be much appreciated.



Barry
 
That was very helpful. The only lingering questions now are:
a. If the 24p is captured at 60i, then what specifically does a 24p camera (DVX100) do special? Just add "flags"?
and
b. How obsolete is my newly purchased dvx100B..as I'm after the 24 look...but seeing HD progressive popping up....and are lower end cams doing 24p with technology booming?
 
Most excellent 24p learning video by the way..even stating the not so obvious negatives like "you don't need this or that".
 
yeah it's like computers...... today you buy the brand new HVX200 and think you're on top of things, and then next week it's the new XVX4000!! i'm kidding, and i know the feeling.

24p to my knowledge does NOT capture at 60i. 24p refers to a video format that operates at a true 24 frames per second (or typically, 23.976fps) framerate with progressive scanning (not interlaced).

if you have any more specific questions you can check out all the wonderfully confusing info here:

http://en.wikipedia.org/wiki/24p
 
On the DVX, the video is taken at 23.976p, but recorded to tape as 60i, with the insertion of pulldown (the Wikipedia article has a fairly good explanation of it -- I wrote it :) ).

When it's captured by Vegas or Premiere Pro 2.0, it's captured as 60i. Then Vegas and Premiere Pro remove the pulldown from the files when they're dropped on a 24p timeline, giving you true 24p files.
 
haha!! very good article dave! so to get this straight so i can actually help someone and myself! :) the tape and the timeline only understand 60i? so the flags that are added just tell the tape and timeline how to interpret the footage?
 
No -- only the TAPE has to be 60i. The timeline is 24p.

The flags are recorded in the 60i stream on the tape in order to tell the NLE which fields to remove in order to restore the original 24p frames. Some NLEs, like Vegas and Premiere Pro 2.0 do the removal on the timeline. Others, like FCP and Avid, remove the pulldown during capture. Either way, you're working with 24p on the timeline.

I didn't write the ENTIRE article, but I wrote a lot of it, including almost all of the pulldown stuff.
 
ok i see. i was partially on the right track. the flags tell the nle to make it 24p and the type of flags would tell it wether it's 24p or 24p(a) correct?
 
Well, it's a different order to the flags, as opposed to a different "type" of flag, but yes, more or less. It doesn't so much tell the NLE to "make it" 24p as it gives the NLE instructions as to how to do it if you so choose.
 
so then technically you could leave it 60i right? if so what would that footage look like?

thanks for the little lesson...... :)
 
It would look interlaced every couple of frames on a progressive display. But it would still look like 24p.

When you play your tape from your camera to a TV (or even to your LCD screen), you're watching it as 60i. But it still looks like 24p.
 
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