Frame Rates...How Does NLE Know?!? at

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Open DV Discussion
For topics which don't fit into any of the other categories.

Thread Tools Search this Thread
Old September 13th, 2013, 09:47 AM   #1
Regular Crew
Join Date: Feb 2010
Location: Freeport, FL
Posts: 39
Frame Rates...How Does NLE Know?!?

Hello, all:

I have a few questions. I'm perplexed about the subject of frame rate and how NLEs "understand" them.

Allow me to begin with some specifics.

I shoot with a Canon Vixia HF21, which captures video in AVCHD. The camera has several frame rate modes. The frame rate I shoot at is PF30, which, according to the documentation, is supposed to be 30FPS; however, in the documentation, there's a little footnote by the 30FPS description. The footnote says that the 30FPS is actually shot at 60i.

Now, that to me means that the video is actually shot at 60 frames per second, interlaced. That also means to me that in order to make the video 30p, it has to combine two of the 60i frames. Fair enough.

Hopefully I'm making sense so far.

Now, I would think that this combining of frames from 60i to 30p would be done in-camera. That's my assumption. Maybe I'm wrong.

Here's why I think I'm wrong. When I import my video into my NLE (Kdenlive), I set my project to be a 30FPS project, but the software screams that the project's frame rate doesn't match the clip! That is, Kdenlive is detecting the clip at 60FPS (59.96, to be exact).

So what gives?

And what happens when I render at 30FPS? If the software is seeing the clip as 60FPS and I render it as 30FPS, what does the software do? Drop the extra frames? And if the answer is yes, doesn't that mean the video is now interlaced?

So confused.

Any light would be so very appreciated!

Norm Kaiser is offline   Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

Omega Broadcast
(512) 251-7778
Austin, TX

(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

(800) 238-8480
Glendale, CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search



All times are GMT -6. The time now is 03:33 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2015 The Digital Video Information Network