I thought I would share the configuration I came up with, in case it is helpful to anyone else.
My use case:
Upload a video, display it on youtube, and then display the video on my site in an emfield.
Setup:
(a) Enable and configure these modules:
emfield, emvideo
media_youtube
media_mover_api, media_mover_cck, media_mover_emfield
(b) Create a cck node type (“video”) with both a filefield (eg “field_filefield_video) and an emvideo field (eg “field_emvideo”)
(c) Create a few video-type nodes. Leave the emvideo field blank, and upload some videos into the filefield.