Editing - Even the Fade In at the beginning is an editing choice. Editing is about the length of the shots as much as it is about the cuts. This film is an example of Classical Editing: It tries to hide the edit from the attention of the audience.
How to hide an edit if you are Robert Wise:
1. Keep the camera moving the same direction.
2. Keep the camera on a similar subject.
3. Keep the camera moving at a similar rate.
4. Hide the edit in a cloud. Yes, really.
5. Mask the edit with continuous sound/music.
Types of edits:
1. Fade: Fading into or out of a scene to a particular color, usually black.
2. Dissolve: Blending over time across two different shots. The length of time matters.
3. Cut: The direct juxtaposition of two different shots.
4. Continuity Edit: A cut which matches the action across the two shots.
5. Match Cut: A match cut which matches the action across SCENES (oooh! fancy!). Not in The Sound of Music.
Other Vocab: M.O.S. - A production term of dubious origin. It means that you don't record sound, just the visuals. Sound may be added later. It could be derived from Fritz Lang's German accent saying "Ve vill film zis Mit out Sound!"
Also, we have ADR which stands for Automated Dialogue Replacement. It's where the actors come into the studio in post-production to overdub their own voices for clearer sound.
And we have the FOLEY ARTISTS who create much of the sound (not sound effects, per se, but just the basic everyday diegetic sounds) we hear in film.