Magic Lantern Forum

Using Magic Lantern => Post-processing Workflow => Topic started by: sdeming on August 10, 2012, 09:07:11 PM

Title: Speed ramping under 24fps back to 24fps - help!
Post by: sdeming on August 10, 2012, 09:07:11 PM
This is more of a frames per second question than anything else.

So I could be using a Canon 5dmII with the Magic Lantern hack, or a Sony FS100 where the frame rates can be selected manually. At the end of the day, the file on the card shows the footage as being shot in a 23.976 capture. You with me?

Now, lets say for instance I shot a sequence at 3fps. The way the footage comes off the card is like this:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 -FRAMES
A A A A A A A B B  B   B    B   B   B   B   B   C  C   C  C   C   C   C  C  -IMAGES ON FRAME

So even though I'm shooting at 3fps, I'm actually getting 24 frames with many of the frames repeated to get me down to 3fps. Still tracking?

My question is how do you go about REMOVING the repeated frames so the footage can be remapped to an actual 23.976 time line.

Obviously, if I'm shooting at 3fps and I do this the footage will be very much sped up, but of course, if you're doing a dangerous stunt (like a car driving by a person's hand in the film Brick) you don't want the mustang driving past at 40mph, you film it slower and then speed it up. I have no idea how to do this when the footage is stored in a 24fps wrapper of sorts.

The same (and more relevant to everyday shooting) question is for filming at 22fps to then speed up to 24 for fight scenes, which is one of the many reasons to get magic lantern.
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: ilguercio on August 10, 2012, 09:11:27 PM
3 fps is 3 fps.
You will get 1 2 3 each second. No frames are repeated.
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: sdeming on August 10, 2012, 09:57:20 PM
Hmm. I'll try it again, but that was not my experience while shooting at 22fps. The file type (when pulled off the card and onto the computer) showed as being 23.976. Am I missing something?
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: ilguercio on August 10, 2012, 10:04:01 PM
FPS override does not change the header. Notes and tips under the INFO about FPS override ;)
The header has to be changed in post, in fact if you notice the file lenght it isn't right ;)
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: sdeming on August 10, 2012, 10:08:41 PM
Ahh, so I am missing something and it's completely obvious. Makes sense, So I just tell my NLE (Premiere) to interpret the footage as 22fps and then I can conform that BACK to 23.976, correct?
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: ilguercio on August 10, 2012, 10:12:49 PM
Yes. Read the instructions of each function BEFORE using it to properly understand how it works. Just to make sure you don't record of shoot something that will result in being unusable or not conform to your expectations later.
It wouldn't be called "FPS override" if it was just a repetition of frames :)
Title: Re: Speed ramping under 24fps back to 24fps - help!
Post by: sdeming on August 10, 2012, 10:34:57 PM
Sure, I'm not exactly sure how to change the header in post with out re-interpreting the footage.

Like I said, this question comes from me shooting on the sony fs100 which does indeed repeat frames. quite annoying. Thanks for your help, I'm very very excited about this feature!