Pause programmatically video player mpv

Question

I would like to know if there is a way to send a message to a running process on linux ?

For example, is it possible to programmatically "pause" a video launched with mpv.

Stratum

There is no general way. The process itself would have to implement something which allowed it to receive messages from outside. Just for pausing though, you can send the process a SIGSTOP. – Tailback

kill -s STOP 13021 and kill -s CONT 13021. Thanks, that's a brilliant work around ! Is it maybe possible to send a key signal too ? – Stratum

What is a "key signal"? – Tailback

sorry keystroke. Like Escape, Spacebar... – Stratum

I use : xdotool key --window "$(xdotool search --class mpv)" p The key P is used to pause the video. – Stratum

Answer 1

To control mpv remotely (eg from another terminal session) you can also start it with the option

--input-ipc-server=/tmp/mpvsocket

and control it by issuing commands like this:

echo '{ "command": ["set_property", "pause", true] }' | socat - /tmp/mpvsocket

See man mpv for (many) more details.

edit: see also mpv --list-properties

edit2: The most simple way I've found to "toggle" pause/play is

{"command": ["cycle", "pause"]}

Grave

with this option by default mpv creates a single socket, which is for the last mpv instance opened. to get multiple sockets per PID, use the mpvSockets plugin – Snowber

Wish I had come across that plugin sooner o_o. Ended up writing my own solution to handle communicating with multiple IPC servers by using the epoch time to create multiple sockets. – Papism

Answer 2

kill -s STOP $(pidof mpv) and kill -s CONT $(pidof mpv)

or better :

xdotool key --window "$(xdotool search --class mpv)" p

The key "P", is set by default to pause the video.

Stratum

Answer 3

It's possible to control mpv through IPC. From the manual mpv(1):

--input-ipc-server=<filename>
       Enable the IPC support and create the listening socket at the given path.

       On  Linux and Unix, the given path is a regular filesystem path.
       On Windows, named pipes are used, so the path refers to the pipe namespace (\\.\pipe\<name>). If the \\.\pipe\ prefix is missing, mpv will add it automatically before creating the pipe, so --input-ipc-server=/tmp/mpv-socket and --input-ipc-server=\\.\pipe\tmp\mpv-socket are equivalent for IPC on Windows.

       See JSON IPC for details.

A couple of examples:

$ echo 'cycle pause'   | socat - /tmp/mpv-socket
$ echo 'playlist-prev' | socat - /tmp/mpv-socket
$ echo 'playlist-next' | socat - /tmp/mpv-socket

See mpv(1) to learn more.

See also:

• https://alexherbo2.github.io/blog/mpv/command-line-controller/
• https://gist.github.com/dwgill/a66769e0edef69c04d3b

Neurogenic