thank you, I think we nailed it now
my response was partly in reply to Jundo's considerations. The expression 'dharma gates' was taken from that part of the discussion.
VLC media player has worked for me and is available for many platforms (I'm using Linux).
MP3 is quite fast, video takes longer.
All generalisations are wrong.
Thank you for asking and answering.
Until now, I had set my timer into two sections (second one normally for kinhin), to add metta practice