“Videos” de-clutter-ification

(I nearly went with clutterectomy, but that would be doing our old servant project a disservice.)

Yesterday, I finally merged the work-in-progress branch porting totem to GStreamer's GTK GL sink widget, undoing a lot of the work done in 2011 and 2014 to port the video widget and then to finally make use of its features.

But GTK has been modernised (in GTK3 but in GTK4 even more so), GStreamer grew a collection of GL plugins, Wayland and VA-API matured and clutter (and its siblings clutter-gtk, and clutter-gst) didn't get the resources they needed to follow.

A screenshot with practically no changes, as expected

The list of bug fixes and enhancements is substantial:

• Makes some files that threw shaders warnings playable
• Fixes resize lag for the widgets embedded in the video widget
• Fixes interactions with widgets on some HDR capable systems, or even widgets disappearing sometimes (!)
  
• Gets rid of the floating blank windows under Wayland
• Should help with tearing, although that's highly dependent on the system
• Hi-DPI support
• Hardware acceleration (through libva)

Until the port to GTK4, we expect a overall drop in performance on systems where there's no VA-API support, and the GTK4 port should bring it to par with the fastest of players available for GNOME.

You can install a Preview version right now by running:

$ flatpak install --user https://flathub.org/beta-repo/appstream/org.gnome.Totem.Devel.flatpakref

and filing bug in the GNOME GitLab.

Next stop, a GTK4 port!

PSA: gnome-settings-daemon's MediaKeys API is going away

 In 2007, Jan Arne Petersen added a D-Bus API to what was still pretty much an import into gnome-control-center of the "acme" utility I wrote to have all the keys on my iBook working.

It switched the code away from remapping keyboard keys to "XF86Audio*", to expecting players to contact the D-Bus daemon and ask to be forwarded key events.

 

Multimedia keys circa 2003

In 2013, we added support for controlling media players using MPRIS, as another interface. Fast-forward to 2021, and MPRIS support is ubiquitous, whether in free software, proprietary applications or even browsers. So we'll be parting with the "org.gnome.SettingsDaemon.MediaKeys" D-Bus API. If your application still wants to work with older versions of GNOME, it is recommended to at least quiet the MediaKeys API's unavailability.

 

Multimedia keys in 2021

 

TL;DR: Remove code that relies on gnome-settings-daemon's MediaKeys API, make sure to add MPRIS support to your app.

power-profiles-daemon: Follow-up

Just about a year after the original announcement, I think it's time to see the progress on power-profiles-daemon.

Note that I would still recommend you read the up-to-date project README if you have questions about why this project was necessary, and why a new project was started rather than building on an existing one.

 The project was born out of the need to make a firmware feature available to end-users for a number of lines of Lenovo laptops for them to be fully usable on Fedora. For that, I worked with Mark Pearson from Lenovo, who wrote the initial kernel support for the feature and served as our link to the Lenovo firmware team, and Hans de Goede, who worked on making the kernel interfaces more generic.

More generic, but in a good way

 With the initial kernel support written for (select) Lenovo laptops, Hans implemented a more generic interface called platform_profile. This interface is now the one that power-profiles-daemon will integrate with, and means that it also supports a number of Microsoft Surface, HP, Lenovo's own Ideapad laptops, and maybe Razer laptops soon.

 The next item to make more generic is Lenovo's "lap detection" which still relies on a custom driver interface. This should be soon transformed into a generic proximity sensor, which will mean I get to work some more on iio-sensor-proxy.

Working those interactions

 power-profiles-dameon landed in a number of distributions, sometimes enabled by default, sometimes not enabled by default (sigh, the less said about that the better), which fortunately meant that we had some early feedback available.

 The goal was always to have the user in control, but we still needed to think carefully about how the UI would look and how users would interact with it when a profile was temporarily unavailable, or the system started a "power saver" mode because battery was running out.

 The latter is something that David Redondo's work on the "HoldProfile" API made possible. Software can programmatically switch to the power-saver or performance profile for the duration of a command. This is useful to switch to the Performance profile when running a compilation (eg. powerprofilesctl jhbuild --no-interact build gnome-shell), or for gnome-settings-daemon to set the power-saver profile when low on battery.

 The aforementioned David Redondo and Kai Uwe Broulik also worked on the KDE interface to power-profiles-daemon, as Florian Müllner implemented the gnome-shell equivalent.

Promised by me, delivered by somebody else :)

 I took this opportunity to update the Power panel in Settings, which shows off the temporary switch to the performance mode, and the setting to automatically switch to power-saver when low on battery.

Low-Power, everywhere

 Talking of which, while it's important for the system to know that they're targetting a power saving behaviour, it's also pretty useful for applications to try and behave better.

 

 Maybe you've already integrated with "low memory" events using GLib, but thanks to Patrick Griffis you can be an event better ecosystem citizen and monitor whether the system is in "Power Saver" mode and adjust your application's behaviour.

 

 This feature will be available in GLib 2.70 along with documentation of useful steps to take. GNOME Software will already be using this functionality to avoid large automated downloads when energy saving is needed.

Availability

 The majority of the above features are available in the GNOME 41 development branches and should get to your favourite GNOME-friendly distribution for their next release, such as Fedora 35.

Sandboxing inside the sandbox: No rogue thumbnailers inside Flatpak

 A couple of years ago, we sandboxed thumbnailers using bubblewrap to avoid drive-by downloads taking advantage of thumbnailers with security issues.

 It's a great tool, and it's a tool that Flatpak relies upon to create its own sandboxes. But that also meant that we couldn't use it inside the Flatpak sandboxes themselves, and those aren't always as closed as they could be, to support legacy applications.

 We've finally implemented support for sandboxing thumbnailers within Flatpak, using the Spawn D-Bus interface (indirectly).

This should all land in GNOME 40, though it should already be possible to integrate it into your Flatpaks. Make sure to use the latest gnome-desktop development version, and that the flatpak-spawn utility is new enough in the runtime you're targeting (it's been updated in the freedesktop.org runtimes #1, #2, #3, but it takes time to trickle down to GNOME versions). Example JSON snippets:

        {
            "name": "flatpak-xdg-utils",
            "buildsystem": "meson",
            "sources": [
                {
                    "type": "git",
                    "url": "https://github.com/flatpak/flatpak-xdg-utils.git",
                    "tag": "1.0.4"
                }
            ]
        },
        {
            "name": "gnome-desktop",
            "buildsystem": "meson",
            "config-opts": ["-Ddebug_tools=true", "-Dudev=disabled"],
            "sources": [
                {
                    "type": "git",
                    "url": "https://gitlab.gnome.org/GNOME/gnome-desktop.git"
                }
            ]
        }  

(We also sped up GStreamer-based thumbnailers by allowing them to use a cache, and added profiling information to the thumbnail test tools, which could prove useful if you want to investigate performance or bugs in that area)

Edit: correct a link, thanks to the commenters for the notice

power-profiles-daemon: new project announcement

Despite what this might look like, I don't actually enjoy starting new projects: it's a lot easier to clean up some build warnings, or add a CI, than it is to start from an empty directory.

But sometimes needs must, and I've just released version 0.1 of such a project. Below you'll find an excerpt from the README, which should answer most of the questions. Please read the README directly in the repository if you're getting to this blog post more than a couple of days after it was first published.

Feel free to file new issues in the tracker if you have ideas on possible power-saving or performance enhancements. Currently the only supported “Performance” mode supported will interact with Intel CPUs with P-State support. More hardware support is planned.

TLDR; this setting in the GNOME 3.40 development branch soon, Fedora packages are done, API docs available:

 

Avoid “Tag: v-3.38.0-fixed-brown-paper-bag”

Over the past couple of (gasp!) decades, I've had my fair share of release blunders: forgetting to clean the tree before making a tarball by hand, forgetting to update the NEWS file, forgetting to push after creating the tarball locally, forgetting to update the appdata file (causing problems on Flathub)...

That's where check-news.sh comes in, to replace the check-news function of the autotools. Ideally you would:

- make sure your CI runs a dist job

- always use a merge request to do releases

- integrate check-news.sh to your meson build (though I would relax the appdata checks for devel releases)

Videos in GNOME 3.38

This is going to be a short post, as changes to Videos have been few and far between in the past couple of releases.

The major change to the latest release is that we've gained Tracker 3 support through a grilo plugin (which meant very few changes to our own code). But the Tracker 3 libraries are incompatible with the Tracker 2 daemon that's usually shipped in distributions, including on this author's development system.

So we made use of the ability of Tracker to run inside a Flatpak sandbox along with the video player, removing the need to have Tracker installed by the distribution, on the host. This should also make it easier to give users control of the directories they want to use to store their movies, in the future.

The release candidate for GNOME 3.38 is available right now as the stable version on Flathub.