Center a movie clip in the Blender VSE I'm making a video with resolution 1920 x 1080 in the 16:9 ratio.
I have a recorded a clip from my phone screen in portrait.
I am using my version of the default Video Editor screen layout. My edit simply has an extra window for a File Explorer.
The clip isn't 16:9 so I first tick Image Offset to stop Blender from stretching the clip, and then make the Blend field Alpha Over in the dropdown list so I can add a background that is 16:9.
The problem I'm having is that the clip is not centered, but anchored to the left. I can change the X Offset value but I can't be certain of what value is exactly centered.
Any help is much appreciated.
Just do some math in the X offset field directly. Look at the Original Dimension of your Clip where you will find out its width x height. Then type into the X offset "1920/2-width/2" (replacing width with the actual one from its Dimensions) and hit Enter. Do the same with Y, typing "1080/2-height/2"...

Or with an Editor/View of the type Python Console opened and the Clip selected in the VSE you should be able to just run this line of code to center your Clip/ImageSequence:

seq = bpy.context.selected_editable_sequences[0]; seq.use_translation = True; seq.transform.offset_x = bpy.context.scene.render.resolution_x/2 - seq.strip_elem_from_frame(bpy.context.scene.frame_current).orig_width/2; seq.transform.offset_y = bpy.context.scene.render.resolution_y/2 - seq.strip_elem_from_frame(bpy.context.scene.frame_current).orig_height/2