Media key

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A Media key is a key with a special purpose for a specific type of applications or operating system functions. Normally, these functions are concerned with media playback, but the term has been used for other functions as well.

A media key can be a dedicated key, or another key can act like a media key in conjunction with the Fn key. Some USB keyboards contain also a knob or roller, usually for volume control.

Gallery

Function-key mappings

On many keyboards, media keys are dedicated keys with no other function.

On some keyboard, media key functions are on Function keys when holding a Fn key.

On the Apple aluminium keyboards with MacOS, the default behaviour is the reverse: numbered function keys are available on the media keys when holding down Fn. This behaviour can be switched in MacOS.

On some PC keyboards from Microsoft, the Fn "key" is not a modifier key but a toggle switch.

Keyboard Fn-F1 Fn-F2 Fn-F3 Fn-F4 Fn-F5 Fn-F6 Fn-F7 Fn-F8 Fn-F9 Fn-F10 Fn-F11 Fn-F12 Other
Apple Aluminium Keyboard A1243 Brightness Down Brightness Up Exposé / Mission Control Dashboard / Launchpad Rewind (Previous track) Play/Pause Fast Forward (Next track) Mute Volume Down Volume Up Eject, F13..F19
Arachnid Recore Play/Pause Stop Previous track Next track Media player Mute Volume Down Volume Up
CMStorm QuickFire Rapid Play/Pause Stop Previous track Next track Mute Volume Down Volume Up
Ducky G2Pro/Shine Mute Volume Down Volume Up Play/Pause Stop Previous track Next track Calculator Computer Email Home/Browser
iOne (Func KB-460, QPad MK-50 etc.) Mute Volume Down Volume Up Play/Pause Previous track Next track
KeyCool 84, KeyCool 87 Computer Home/Browser Calculator Media Player Previous Track Next Track Play/Pause Stop Mute Volume Down Volume Up (Windows lock)
KeyCool 108 Computer Home/Browser Mail Media Player Previous Track Next Track Play/Pause Stop Mute Volume Down Volume Up (Windows lock) Lock Sleep, Calculator, ... ?
Matias Quiet Pro Mini (PC) Rewind (Previous track) Forward (Next track) Play/Pause on Esc, Mute Volume Up/Down on Fn-Arrow key
Max Keyboard Blackbird Mute Volume Down Volume Up Play/Pause Previous Track Next Track
Mionix Zibal 60 Mute Volume Down Volume Up Play/Pause Stop Previous Track Next Track
Noppoo Lolita My Computer Web Browser Calculator Media Player Previous Track Next Track Play/Pause (NKRO) Mute Volume Down Volume Up
Noppoo Lolita Spyder Previous Track Play/Pause Next Track Stop Mute Volume Down Volume Up
Plum 96 Mute Volume Down Volume Up Play/Pause Previous Track Next Track Home/Browser My computer (Debounce dec) (Debounce inc)
SteelSeries 6GV2 Mute Volume Down Volume Up Play/Pause Previous Track Next Track

Protocol

Media keys usually emit distinct codes to the host.

USB

In the USB HID ("Human Interface Device") standard, while most key codes are in the "Keyboard/Keypad" usage page (0x07), most most media keys are in "Consumer" usage page (0x0C). System control keys (Power, Sleep, Wake) are in the "Generic Desktop" usage page (0x01).

The "Consumer Usage Page" has also codes for linear relative values for volume control, bass and treble. While it may appear to be analogue, the knob or roller is usually connected to a rotary encoder. The values are relative to the volume level set by the user in the operating system and application software. If the controls had absolute values, they would have needed to be motorized and under computer control, which is something that the USB HID specification does not support.

The controls in each Usage Page are transmitted in a separate packet. Therefore, media keys may have separate rollover characteristics from regular keys.

PS/2

For PS/2, Microsoft has standardized media key scancodes for Windows.

Some vendors have used their own codes that have been activated first after having received a "magic" code from the host's keyboard driver.

References