Comments

John_Cline wrote on 2/5/2009, 4:51 PM
You can do what they've done for years, speed up the video and audio about 4.17% from 24 to 25 frames per second.
farss wrote on 2/5/2009, 4:52 PM
24p to 25p is fairly trivial in Vegas. Many posts regarding this here.
Your biggest challenge can be the audio. Vegas may be good enough (has been good enough for me) or not. If not (solo acoustic instruments) look for solutions from Zplane (ships with latest ACID) or the MPEX3 plug that runs in Pyramix. The later comes highly recommended to me.

Bob.
Patryk Rebisz wrote on 2/6/2009, 11:50 AM
what do you mean about the audio issues?
P
Coursedesign wrote on 2/6/2009, 11:59 AM
It's difficult to do a "constant pitch" audio speed change with high quality.

johnmeyer wrote on 2/6/2009, 2:06 PM
To expand, if you simply speed up the footage (which you can actually do with some file formats with a simple file patcher which changes the header and tells the program to play back and the faster speed) -- if you do just this simple speed up, the pitch will go up by a noticeable amount. If this is not what you want (and I definitely would not want that), you can use some of the Vegas or Sound Forge magic, and speed up the audio by 25/24, but keep the pitch constant.

How is this done? Well, these days it is done mathematically, but the way to think about what this math does is to imagine having the sound on tape, and then slicing across this tape millions of times so you have millions of little slivers of tape. Then, every 25th sliver, throw one out, and then tape them all back together. When you play back the tape, everything is going past the head at the same speed as before, so the pitch doesn't change, but since those little slivers are missing, the tape finishes in 24/25 of the time.

Obviously you can't do this physical feat, and the mathematical version can't duplicate it exactly and therefore introduces errors that are quite audible for certain types of music. As a result, most software gives you several algorithms to choose from, and you can often find one that works well for the particular material you are shortening. Sound Forge, I think, has many more options than those built into Vegas.
Patryk Rebisz wrote on 2/7/2009, 1:15 PM
Can i just drop the 24p footage on 25p sequence and turning off Frame Blending let it skip 1 frame per second? Will that work?
John_Cline wrote on 2/7/2009, 1:28 PM
"turning off Frame Blending let it skip 1 frame per second?"

No, you would really notice that.
farss wrote on 2/7/2009, 3:09 PM
Based on suggestions here I did try this. I didn't notice it but others feel it is objectionable. Vimeo does this with 25fps material and you can at times see the jump.
Going from 24p to 25p Vegas would have to duplicate a frame.

The old PAL telecines just left the pitch shift as was. Most viewers accepted it. Modern telecines do shift pitch back. I'm very reliably told it can fail requiring intervention.

If this is a high value shoot the cost of getting someone with the right tools to do it right would be trivial. Should only cost in the $100s

Bob.