Canon EOS-1D X Mark II Manual (en)

Drag the frame position slider left or right to display 
the ending frame, and then click the Out point 
The Out point marker is now displayed, and the ending point for 
still images to save is set.
You can also click this button during movie playback to specify 
the Out point.
Once you have specified the Out point, you can jump to the 
frame at the Out point by clicking the [ 
 ] (move to OUT point) 
button. If no Out point has been set, clicking this button jumps to 
the last frame. You can also click the [ 
 ] (move to OUT point) 
button during movie playback.
The maximum range between In and Out points is one hour.
The In and Out points can be removed from [Marker] on the main 
window menu.
Select [Delete IN point], [Delete OUT point], or [Delete both IN 
point and OUT point] as required.
Out point button
Out point marker
Click the Capture multiple still images button.
Still images are saved following the settings in the [Still Image 
Capture Settings] dialog box. All frames between the In and Out 
points are saved as still images.
You can also click this button during movie playback to save still 
images. In this case, playback is paused during capture.
Capture multiple still images button
The In and Out point settings in the selected clip are saved 
automatically, and the settings continue to be effective the next time 
you work with the clip in EMU.