For practicing I use "The Amazing Slow Downer" which is a looper that allows you to vary the tempo and/or pitch of an audio track.
For recording I use "Audacity" (free) which allows you to vary an imported backing track before you record over it.
I'm sure there are more recent applications that allow you to this "all in one".
I have "Video Surgeon", but have never used it.
Once I've watched Griff's breakdown I then work strictly from the audio.