Issue with programme script preview BBC video context module

[pietrop]

Describe the bug
A clear and concise description of what the bug is.

the interface quite laggy and the video playback unreliable and the sound strangely reverberant, as if more than
one file is playing back simultaneously but ever so slightly out of sync.

originally raised by @motioncircus in pietrop/digital-paper-edit-electron#73 (comment)

To Reproduce
Steps to reproduce the behavior:

see paper-edit user manual preview section

Expected behavior
to not have any lags and "double sound"

Screenshots
NA

Additional context
best guess, multiple instances of the player are being initialized?