Gallery - LG G4 User Manual

NOTE Tap once when two displays are a different status (i.e. the monitor
is playing a video and your phone's video applications is displaying an empty
screen), then Dual Play will start. Dual Play operates at 1280X720 or higher
display resolution.

Gallery

1
NOTE
Depending on the software installed, some file formats may not be
supported.
Some files may not play properly due to their encoding.
Viewing pictures
Camera and Video