Hi folks - this is a work in progress but I thought I’d share what I’m doing. I’m making a video for flute players/ teachers. I’ve arranged Ferdinand Herold’s CLOG DANCE from his ballet “La Fille Mal Gardee” (music originally for orchestra) for flute and piano and I’m replacing the audio of a live performance with this flute arrangement.
My goal is to synch the audio exactly with the dancing on stage. Rather than try to synch the video to the audio, I’m synching the audio to the video (!)
So here’s what I’ve done so far:
- Arranged the music for flute and piano and notated it using MuseScore.
- Exported the MuseScore file as a musicxml file.
- Imported the musicxml file into a MIDI track in Cubase and set it to a VST piano sound.
- Captured a YouTube ballet video featuring dancers from the Royal Ballet.
- Imported the mp4 into Shotcut and exported just the audio as an mp3 file.
- Imported the mp3 into Cubase on an audio track.
- Set the Cubase internal metronome going.
- Meticulously changed the tempo track in Cubase so that the metronome click fits EXACTLY to the audio track.
- Recorded my live flute along to the piano track, on another audio track, using the Cubase metronome (click track) as a guide.
- Mixed the flute and piano tracks, adding reverb on the flute. Exported the flute/piano tracks as an mp3.
- Imported the original video into Shotcut, deleted the original orchestra audio and replaced it with the piano/flute track. Exported the mp4 …
Ta DA - synchronisation achieved!
Here’s the video:
It’s not quite completed because I have yet to re-record my flute on bits of the flute track because some sections are slightly out-of-time, and also I split a couple of notes. Tut -tut, must do more practice!! 
I was amazed at how much I had to adjust the tempo in Cubase. Here’s a screenshot of the Cubase project. The tempo track had to be adjusted SO much!
Anyway, hope this is useful and interesting for someone.