I have an MTS file recorded at 60pfs.
I want to save a version of it that's playing at 1/2 speed with 30fps, which I can e.g. upload to Youtube for such slow motion playback there.
How can I do that with some OS X tool(s)?
If you want to install FFmpeg, do so by installing Homebrew first, then
All you have to do is:
This often works better than just setting a different framerate. If you were to set a lower framerate, all FFmpeg would is drop the frames in between. You'd end up with a video of the same duration, but no real slow motion.
If you want to use
… where you can set the speed factor manually.
AviDemux seems to be the way to go: http://fixounet.free.fr/avidemux/
You can change the Framerate by going to Video > Framerate and setting it as 30fps.
Here's a blog describing how to export it for YouTube on Windows, but the process should be similar on a OS X. http://greeenjava.blogspot.com.au/2011/01/easy-steps-to-create-hd-video-for.html