Which PDFs work best
A PDF exported from MuseScore, Sibelius, Finale, Dorico, LilyPond or Guitar Pro is the best start: every note in it is a real symbol, so each one is read exactly.
A scan or a photo of a page is a picture of the music. It takes longer to read and may need a few notes checked in the studio, so a file from notation software is worth using when you have one.
If a note looks wrong in the preview, open the video in the studio, where the score editor can fix it before you export.