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Firefox

Install Firefox via these packages (adjust for your desired locale):

pacman -S firefox firefox-i18n-de

Wayland

Wayland is not yet the default display manager for Firefox (it falls back to XWayland on Wayland). To enableforce nativeFirefox to use Wayland renderingyou in Firefoxcan set the following:MOZ_ENABLE_WAYLAND environment variable to 1. Use user specific systemd environment variable configs to set it:

echo "MOZ_ENABLE_WAYLAND=1" >> ~/etc/environment.config/environment.d/moz_wayland.conf

Alternatively, navigate to about:config and set gfx.webrender.all to true to enable WebRender compositor.

Media Playback

Autoplay in background

Firefox prevents autoplay for media of tabs that aren't currently active, which causes apps like Plex to take very long to skip to the next track after the current one has ended. The following setting in about:config can be used to disable this behavior:

Setting key Value Description
media.block-autoplay-until-in-foreground false Enable autoplay when tab is not currently active

Hardware Decoding

Utilizing GPU hardware accelerated decoding of video content results in smoother playback of HD/4K content, while reducing CPU load and power draw.draw Set(important to save on battery on laptops).

To ensure Firefox uses hardware decoding ensure the followingfollowing:

in
  • The necessary VA-API drivers are installed (see: Graphics Cards)
  • Navigate to about:support and ensure that under Compositing it says WebRender (WebRender Software will not work)
  • Navigate to about:config toand enableset hardware accelerated video playback in Firefox:

    running
    Setting keyValueDescription
    gfx.webrender.alltrueEnable the WebRender compositor
    media.ffmpeg.vaapi.enabled to true Enable VA-API
  • If decoder
    		•
    media.ffvpx.enabledfalseDisable internal VP8/9 software decoders
    media.rdd-vpx.enabledfalseDisable codec sandbox for VP8/9
    media.navigator.mediadatadecoder_vpx_enabledtrueEnable hardware encoding for WebRTC

    Alternatively, you can set an environment variable toWayland, enable theWayland WebRendermode compositor:

    echo "MOZ_WEBRENDER=1" >> /etc/environment

    Additionally, starting within Firefox 98,(see youabove)

    • need to disable the RDD sandbox in order to use VA-API hardware accelerated video decoding. Otherwise no videos will play:

    echo "MOZ_DISABLE_RDD_SANDBOX=1" >> /etc/environment

To test if Firefox is actually using VA-API to decode video you can launch it with the following command:

MOZ_LOG="PlatformDecoderModule:FFmpegVideo:5" firefox 2>&1 | grep 'VA-API'

If your log output reads something like the following video decoding via VA-API is working.

[Child 55975: MediaPDecoder #3]: D/PlatformDecoderModule VA-API Got one frame output with pts=135468000dts=135468000 duration=17000 opaque=-9223372036854775808
[Child 55975: MediaPDecoder #3]: D/PlatformDecoderModule Reusing VA-API DMABufSurface UID = 10

KDE Plasma Integration

Control media playback from KDE

For better integration of Firefox into the KDE Plasma desktop, install the Plasma Integration add-on either via the Mozilla Add-on page or via AUR:

TIP: To prevent duplicate entries in the Media Player widget or tray icon, set media.hardwaremediakeys.enabled to false. This disables the media entry from Firefox and only uses the one from the Plasma integration add-on.

yay -S firefox-extension-plasma-integration

Make Firefox use KDE Dialogs

By default, Firefox uses GTK file and print dialogs, even on KDE. To change this to KDE native dialogs set one of the following:

  • Set widget.use-xdg-desktop-portal to true in about:config
  • Launch Firefox with GTK_USE_PORTAL=1 environment variable
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