I find Encore to be very temperamental when trying to achieve a Motion Background.
I have achieved this once or twice, and if I’m being honest, I still wouldn’t exactly know how to give somebody step-by-step instructions. Basically, in the Layers panel in both Encore and Photoshop, I have ticked the layer visibility (eye) on and off on multiple layers, saved the .psd file etc. until my video background appears in Encore.
I think Charles has the answer, being that the background layer in Photoshop has to be visible, even though it may not contain any pixels. Then Encore will determine that your video is your ‘Background’ and will lock it in the Layers panel. But again, I’m still not certain how it all works.
I hope you guys can figure it out,
Jayden