Can I send a keyboard shortcut to two applications (e.g. Audacity and VLC) and at the same time?

Question

I am on Fedora 25 (x86_64) and I use XFCE desktop. I need to record a sound in sync with a video. Recording is done by Audacity and video playback is done by VLC. Currently, I have set global keyboard shortcut for VLC to pause and play the video when I want. I use another keyboard shortcut in Audacity (not global) to append my voice to the sound being recorded and I hit space (local) to pause the recording. You see that this makes the recording asynchronous to the video playback, which sucks!
My question is how can I define global keyboard shortcuts for my desktop (currently XFCE but I can use other desktop environments on my Fedora if necessary), to start playback and record at the same time (with a single key [combination] and pause them so (with a single key [combination]) as well?

To make the question clearer, for example I have set CTRL+ALT+SPACE as global hotkey for VLC for play/pause. How can I define the same key combination for Audacity to do Append Record/Pause when I send this key combination to the system?

Answer 1

You cannot directly route a key press to two applications. You need to capture the key press in some keyboard macro service and forward it to the two applications.

I don't know if XFCE includes a keyboard macro facility that could do the job. You can do this in an environment-agnostic way with xbindkeys to capture the key press and xdotool to simulate a key press in a window. In your ~/.xbindkeysrc, put something like

"xdotool search --name Audacity key Ctrl+Alt+Space; xdotool search VLC Ctrl+Alt+Space"
Ctrl+Alt+Space