DElauncher4Kodi 1.2

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Table of Contents

1. Introduction
2. Installation
3. Ear safety warning
4. Implementation details
5. Uninstalling
6. Troubleshooting

Introduction

Running kodi as well as a desktop environment (DE) such as gnome-shell on the same computer requires a bit of...cooperation...between the two. The following two problems exist for anyone trying to do this:

• When running kodi from within gnome-shell, the media keys may be handled by the desktop environment instead of by kodi. That means the play/pause/rewind/etc media keys on a remote or keyboard don't work, and the volume up/down keys, which modify the system volume rather than kodi's volume, work but show an obnoxious popup and make an annoying sound (the same as when you change the volume in gnome-shell normally).

• When running kodi as a separate session (as in, selecting it from the login screen), the media keys work, but the volume keys control the kodi app volume. This is nice, except that the maximum volume is limited to the system volume setting, which is left at whatever it was last set to by the user in gnome- shell, and is now not adjustable within kodi. Also, running kodi as a separate desktop session is a pain in the neck if you actually want to switch between kodi and gnome-shell (to watch netflix in chrome or whatever), since typing passwords on tiny keyboards on HTPC remotes is annoying, and enabling passwordless login is bad security practice (and annoying to set up). Also media computers are often slow for things that are not GPU accelerated, so logging out and in again can be pretty slow.

DElauncher4Kodi solves both problems by setting the system volume to 100% before launching kodi, and grabbing all keyboard input and forwarding media keys as commands to kodi directly.

It should work on all desktop environments, not just gnome-shell. It only assumes you are running linux and PulseAudio.

Installation

To install, run:

sudo pip3 install DElauncher4Kodi

and then reboot.

(replace pip3 with pip if that is what the pip binary for Python 3 is called on your computer. Python 3.6+ required)

A new launcher should appear in your DE's menu/launcher called "DE launcher for Kodi". Running that instead of the ordinary kodi launcher will turn on the volume change and media key redirection, run kodi, then restore things to normal once kodi exits. You can continue to use your DE while kodi is running, on a separate monitor, by switching workspaces, or pressing, alt-tab or whatever, but there will be no audio other than kodi and media keys will not have any effect on any programs other than kodi.

to uninstall, run:

sudo pip3 uninstall DElauncher4Kodi

Ear safety warning

Because DElauncher4Kodi sets the system volume to 100%, either a bug in my program or deliberate modification of PulseAudio settings by the user whilst kodi is running has the potential to allow other running applications to output audio at 100% volume. For the safety of your ears should this occur, do not use DElauncher4Kodi with headphones. You have been warned.

Implementation details

Media key forwarding

DElauncher4Kodi uses the linux kernel's evdev library to capture all key events from devices that have media keys. If an event corresponds to one of the media keys DElauncher4Kodi knows about, it sends the appropriate command to kodi over its UDP interface on localhost:9777. Otherwise, it forwards the event to a uinput device (using the kernel's uinput library) such that it appears to the system as an ordinary keypress, which the window manager will receive as normal. This latter forwarding of events back to the system requires DElauncher4Kodi either run as root, or have permission to write to /dev/uinput. The installer configures a udev rule to allow the uinput group to write to /dev/uinput and adds the user to that group. DElauncher4Kodi will therefore only be able to forward media keys when run as that user - other users need to be added to the uinput group in order for it to work for them too.

Audio levels

DElauncher4Kodi performs the following actions before starting kodi using the pulseaudio library:

• Notes the current volume and mute state of the current output

• Sets a 'null sink' as the default output so that any new applications will not output any audio

• Moves any existing audio output to the null sink to stop them producing audio

• Sets the real output to 100% volume and unmuted

Once kodi starts, its audio output is moved to the real output (as it is initially set to the null sink, since the null sink was default). Then, once kodi exits, DElauncher4Kodi

• Restores the volume and mute state of the output

• Deletes the null sink

• Moves all application output back to whatever device they were outputting to beforehand.

This has the effect of silencing all audio other than kodi whilst kodi is running

Uninstalling

sudo pip3 uninstall DElauncher4Kodi will remove all files added by the installer. If you installed without pip, you will need to delete them manually.

Installation performs the following actions:

• Installs Python package DElauncher4Kodi

• Adds a udev rule /etc/udev/rules.d/99-DElauncher4Kodi-uinput-group-access.rules

• Creates group uinput if it does not exist

• Adds the current user to the groups uinput and input

• Adds a desktop file to /usr/local/share/applications/DElauncher4Kodi.desktop

Uninstalling with pip will not remove the user from the uinput and input groups or delete the uinput group. Run sudo delgroup uinput; sudo deluser $USER input to do this. However, it's possible that the user was already in the input group for some other reason, so removing them from the group may interfere with other software.

Troubleshooting

Plugging in a keyboard or wireless remote after starting kodi? Sorry, DElauncher4Kodi doesn't support hot-plugging - you'll have to restart kodi before the media keys on a newly plugged in device will be correctly forwarded to kodi.

Something else not working? Try running DElauncher4Kodi from the command line:

python3 -m DElauncher4Kodi kodi

And see if the output it produces explains what's wrong. For example, only one instance of DElauncher4Kodi can run at a time, and if it doesn't shut down properly, it will display an error because it thinks another instance is still running. This can be fixed by rebooting or by deleting the lock file /tmp/DElauncher4Kodi.lock. If you are seeing Python tracebacks in the terminal output, this indicates either a bug in my code or something I didn't anticipate might go wrong. Please report this as an issue on github so I can fix it.

Example terminal output

This is what the terminal output should look like when everything is running correctly:

$ /usr/bin/python3 -m DElauncher4Kodi kodi
This is DElauncher4Kodi version 1.2.0.
Please report bugs to github.com/chrisjbillington/DElauncher4Kodi/

Initiating key capturing
  Capturing media keys from:
    /dev/input/event21: lircd-uinput
    /dev/input/event14: Dell WMI hotkeys
    /dev/input/event11: Intel HID events
    /dev/input/event4: AT Translated Set 2 keyboard
Key capturing setup complete

Initiating audio reconfiguration
  Getting current default sink info:
    name: alsa_output.pci-0000_00_1f.3.analog-stereo
    volume: 28 %
    mute: False
  Creating null sink as default sink:
    name: DElauncher4Kodi.nullsink_
    module #: 98
  Moving exising audio streams to null sink:
    Spotify
  Setting original default sink to 100 % volume
Audio reconfiguration complete pending kodi startup

Starting kodi...
Waiting for kodi audio stream to appear
  Audio stream has appeared
  moving kodi audio stream to original default sink
Kodi exited

Stopping key capturing
Key capturing stopped

Restoring audio configuration
  Setting original default sink to 0 % volume
  Restoring original default sink
  Moving streams back to default sink:
    Spotify
  Unloading null sink module
  Restoring original volume
Audio configuration restored

Done