Match movie frame length with background image?

Probably a noob question but I’m messing around with the movie clip feature for Background Images so I use references for animations I need to make. On the Blender wiki it says there is an option in the Properties panel called Match Movie Length which will set the number of frames in Blender to match the length of the movie clip. But I don’t see that option in the Properties panel anywhere. Where/how do I enable that option?

On the 3d view press “n” and enable “Background images”
You have to treat the reference footage as an image sequence (even if it is on a video format like avi or quicktime). Don’t ask me why, I puzzle about that myself.



This will make frame 1 on your reference footage match with frame one on blender’s time line. It will not readjust the length of your time line to match that of your reference footage.

That’s weird

But functionally, setting it as an image sequence is the same as it being set as a movie clip?