Different frame rates in Premiere Pro
One of the good things about making mistakes is that if you screw up large enough, you’ll probably never make that same mistake again. For example, one time when I was going to film a concert, I failed to contact the sound engineer beforehand to check what type of equipment I would need to record the sound from the mixer. This, in combination with the fact that pretty much all my backup solutions failed as well, resulted in me having to record the sound from the PA as it sounded in the room with only a SM58 (frankly, it wouldn’t have mattered which microphone I had). Obviously, that didn’t work out very well. In fact, the end result sounded like utter crap. However, for the next concert, I came prepared and even did a sound check beforehand. I’ll never record crappy sound again.
The latest in the row of these productive mistakes I did a couple of days ago when I got the bright idea to put together a sort of show reel of all the videos I’ve created so far. What never really struck me, or at least didn’t alarm me, was that the material I’ve got had different frame rates. Some of it is in 23.976 frames per second, some of it in 24, and some of it in 25. You wanna know what happens when you mix these indiscriminately in Premiere Pro? Total mayhem ensues, that’s what happens! Random frames enter your footage, without warning individual frames gets scaled up, and if you’re lucky enough to avoid these quirks for some scenes, you can pretty much count on it stuttering its way forward, making it look like your subjects have some kind of glitchy spasm thingy going on. In short, you don’t want this unless your movie will be shown at some post modernistic film festival where you can explain it away as avant-garde art.
So, what’s the solution? Well, it’s pretty easy actually. Before starting to edit your piece, decide on the frame rate you want to work in, then, in the project tile, right click on the video clip that doesn’t match your desired frame rate and choose Modify > Interpret Footage. In the pop-up window that appears, you’ll be able to choose a new frame rate for the clip. Just bear in mind that this will slow down or speed up your clip depending on if you’re decreasing or increasing the frame rate. Also, the sound is affected as well, so that masculine voice that you recorded might end up sounding a little bit more feminine.
In addition, when making these changes, if you’ve already edited some footage, this will get screwed up. This is because all the cut points and key frames are encoded according to their time stamp, not according to the number of frames. This, in turn, means that you’ll have to go through all your edits and adjust them. If your clips are relatively short, this is less of a problem. If you, on the other hand, are working with really long clips, you’ll be unhappy to know that your cut points and keyframes will have moved away several minutes from where they’re supposed to be. This is what I realised had happened to my piece, and that’s why I’ll never make this mistake again.