Electrical power input is the amount of power that flows from the socket or power supply. The output is always lower than the input. This is where the concept of perpetual motion comes into play, because there will always be some energy loss (thermal, motion or sound). This creates the difference between input power and output power.
Backlight bleeding is a phenomenon seen in LCD monitors, which is characterized by uneven backlight illumination, especially in dark scenes with minimal ambient illumination. It occurs mainly in IPS panels around the corners or edges. Sometimes this is called IPS glow or light bleeding.