The 'Out FPS:' meter shows you how fast your computer is able to extract the image, track the face, produce animation results, and then stream a frame of data. As you can imagine it requires a lot of processing. If you're seeing a lower 'Out FPS' than 'Video FPS' it's because your CPU is currently unable to process the images fast enough. Try lowering the video resolution to improve the FPS. Also make sure Live Server is running on a dedicated machine and close other applications.
Rotating the video is also a common culprit for slowing down your 'Out FPS'. If possible, try to rotate the camera instead of rotating the image in Live Server.