Search Results: "Matthias Geiger"

9 November 2025

Stefano Rivera: Debian Video Team Sprint: November 2025

This week, some of the DebConf Video Team met in Herefordshire (UK) for a sprint. We didn't have a sprint in 2024, and it was sorely needed, now. At the sprint we made good progress towards using Voctomix 2 more reliably, and made plans for our future hardware needs. Attendees Voctomix 2 DebConf 25 was the first event that the team used Voctomix version 2. Testing it during DebCamp 25 (the week before DebConf), it seemed to work reliably. But during the event, we hit repeated audio dropout issues, that affected about 18 of our recordings (and live streams). We had attempted to use Voctomix 2 at DebConf 24, and quickly rolled back to version 1, on day 1 of the conference, when we hit similar issues. We thought these issues would be resolved for DebConf 25, by using more powerful (newer) mixing machines. Trying to get to the bottom of these issues was the main focus of the sprint. Nicolas brought 2 of Debian's cameras and the Framework laptop that we'd used at the conference, so we could reproduce the problem. It didn't take long to reproduce, in fact, we spent most of the week trying any configuration changes we could think of to avoid it. The issue we've been seeing feels like a gstreamer bug, rather than something voctomix is doing incorrectly. If anything, configuration changes are avoiding hitting it. Finally, on the last night of the sprint, we managed to run voctomix all night without the problem appearing. But... that isn't enough to feel confident that the issue is avoided. More testing will be required. Detecting audio breakage Kyle worked on a way to report the audio quality in our Prometheus exporter, so we can automatically detect this kind of audio breakage. This was implemented in helios our audio level monitor, and lead to some related code refactoring. Framework Laptops Historically, the video team has relied on borrowed and rented computer hardware at conferences for our (software) video mixing, streaming, storage and encoding. Many years ago, we'd even typically have a local Debian mirror and upload queue on site. Our video mixing machines had to be desktop size computers with 2 Blackmagic Declink Mini Recorder PCI-e cards installed in them, to capture video from our cameras. Now that we reliably have more Internet bandwidth than we really need, at our conference venues, we can rely on offsite cloud servers. We only need the video capture and mixing machines on site. Blackmagic also has UltraStudio Recorder thunderbolt capture boxes that we can use with a laptop. The project bought a couple of these and a Framework 13 AMD laptop to test at DebConf 25. We used it in production at DebConf, in the "Petit Amphi" room, where it seemed to work fairly well. It was very picky about thunderbolt cable and port combinations, refusing to even boot when they were connected. Since then, Framework firmware has fixed these issues, and in our testing at the sprint, it worked almost perfectly. (One of the capture boxes got into a broken state, and had to be unplugged and re-connected to fix it.) We think these are the best option for the future, and plan to ask the project to buy some more of them. HDCP Apple Silicon devices seem to like to HDCP-encrypt their HDMI output whenever possible. This causes our HDMI capture hardware to display an "Encrypted" error, rather than any useful image. Chris experimented with a few different devices to strip HDCP from HDMI video, at least 2 of them worked. Spring Cleaning Kyle dug through the open issues in our Salsa repositories and cleaned up some issues. DebConf 25 Video Encoding The core video team at DebConf 25 was a little under-staffed, significantly overlapping with core conference organization, which took priority. That, combined with the Voctomix 2 audio dropout issues we'd hit, meant that there was quite a bit of work left to be done to get the conference videos properly encoded and released. We found that the encodings had been done at the wrong resolution, which forced a re-encode of all videos. In the process, we reviewed videos for audio issues and made a list of the ones that need more work. We ran out of time and this work isn't done, yet. DebConf 26 Preparation Kyle reviewed floorplans and photographs of the proposed DebConf 26 talk venues, and build up a list of A/V kit that we'll need to hire. Carl's Video Box Carl uses much of the same stack as the video team, for many other events in the US. He has experimenting with using a Dell 7212 tablet in an all-in-one laser-cut box. Carl demonstrated this box, which could perfect for small miniDebConfs, at the sprint. Using voctomix 2 on the box requires some work, because it doesn't use Blackmagic cards for video capture. The Box: Front The Box: Back gst-fallbacksrc Carl's box's needs lead to looking at gstfallbacksrc. This should let Voctomix 2 survive cameras (or network sources) going away for a moment. Matthias Geiger packaged it for us, and it's now in Debian NEW. Thanks! voctomix-outcasts Carl cut a release of voctomix-outcasts and Stefano uploaded it to unstable. Ansible Configuration The videoteam's stack is deployed with Ansible, and almost everything we do involves work on this stack. Carl upstreamed some of his features to us, and we updated our voctomix2 configuration to take advantage of our experiments at the sprint. Miscellaneous Voctomix contributions We fixed a couple of minor bugs in voctomix. More Nageru experimentation In 2023, we tried to configure Nageru (another live video mixer) for the video team's needs. Like voctomix it needs some configuration and scaffolding to adapt it to your needs. Practically, this means writing a "theme" in Lua that controls the mixer. The team still has a preference for Voctomix (as we're all very familiar with it), but would like to have Nageru available as an option when we need it. We fixed some minor issues in our theme, enough to get it running again, on the Framework laptop. Much more work is needed to really make it a useable option. Thank you Thanks to the Debian project for funding the costs of the sprint, and Chris Boot's extended family for providing us with a no-cost sprint venue. Thanks to c3voc for developing and maintaining voctomix, and helping us to debug issues in it. Thank you to everyone in the videoteam who attended or helped out remotely! And to employers who let us work on Debian on company time. We'll likely need to keep working on our stack remotely, in the leadup to DebConf 26, and/or have another sprint before then. Breakfast Coffee Hacklab Trains!

22 August 2025

Matthias Geiger: Enforcing darkmode for QT programs under a non-QT based environment

I use sway as window manager on my main machine. As I prefer dark mode, I looked for a way to enable dark mode everywhere. For GTK-based this is fairly straightforward: Just install whatever theme you prefer, and apply it. However, QT-based applications on a non-QT based desktop will look

3 July 2025

Matthias Geiger: Using the debputy language server in Debian (with neovim)

Since some time now debputy is available in the archive. It is a declarative buildsystem for debian packages, but also includes a Language Server (LS) part. A LS is a binary can hook into any client (editor) supporting the LSP (Language Server Protocol) and deliver syntax highlighting, completions, warnings and

29 June 2025

Matthias Geiger: Hello world

I finally got around to setting up a blog with pelican as SSG, so here I will be posting about my various Debian-related activities.

9 March 2025

Niels Thykier: Improving Debian packaging in Kate

The other day, I noted that the emacs integration with debputy stopped working. After debugging for a while, I realized that emacs no longer sent the didOpen notification that is expected of it, which confused debputy. At this point, I was already several hours into the debugging and I noted there was some discussions on debian-devel about emacs and byte compilation not working. So I figured I would shelve the emacs problem for now. But I needed an LSP capable editor and with my vi skills leaving much to be desired, I skipped out on vim-youcompleteme. Instead, I pulled out kate, which I had not been using for years. It had LSP support, so it would fine, right? Well, no. Turns out that debputy LSP support had some assumptions that worked for emacs but not kate. Plus once you start down the rabbit hole, you stumble on things you missed previously.
Getting started First order of business was to tell kate about debputy. Conveniently, kate has a configuration tab for adding language servers in a JSON format right next to the tab where you can see its configuration for built-in LSP (also in JSON format9. So a quick bit of copy-paste magic and that was done. Yesterday, I opened an MR against upstream to have the configuration added (https://invent.kde.org/utilities/kate/-/merge_requests/1748) and they already merged it. Today, I then filed a wishlist against kate in Debian to have the Debian maintainers cherry-pick it, so it works out of the box for Trixie (https://bugs.debian.org/1099876). So far so good.
Inlay hint woes Since July (2024), debputy has support for Inlay hints. They are basically small bits of text that the LSP server can ask the editor to inject into the text to provide hints to the reader. Typically, you see them used to provide typing hints, where the editor or the underlying LSP server has figured out the type of a variable or expression that you did not explicitly type. Another common use case is to inject the parameter name for positional arguments when calling a function, so the user do not have to count the position to figure out which value is passed as which parameter. In debputy, I have been using the Inlay hints to show inherited fields in debian/control. As an example, if you have a definition like: 
Source: foo-src
Section: devel
Priority: optional
Package: foo-bin
Architecture: any
Then foo-bin inherits the Section and Priority field since it does not supply its own. Previously, debputy would that by injecting the fields themselves and their value just below the Package field as if you had typed them out directly. The editor always renders Inlay hints distinctly from regular text, so there was no risk of confusion and it made the text look like a valid debian/control file end to end. The result looked something like: 
Source: foo-src
Section: devel
Priority: optional
Package: foo-bin
Section: devel
Priority: optional
Architecture: any
With the second instances of Section and Priority being rendered differently than its surrendering (usually faded or colorlessly). Unfortunately, kate did not like injecting Inlay hints with a newline in them, which was needed for this trick. Reading into the LSP specs, it says nothing about multi-line Inlay hints being a thing and I figured I would see this problem again with other editors if I left it be. I ended up changing the Inlay hints to be placed at the end of the Package field and then included surrounding () for better visuals. So now, it looks like: 
Source: foo-src
Section: devel
Priority: optional
Package: foo-bin  (Section: devel)  (Priority: optional)
Architecture: any
Unfortunately, it is no longer 1:1 with the underlying syntax which I liked about the previous one. But it works in more editors and is still explicit. I also removed the Inlay hint for the Homepage field. It takes too much space and I have yet to meet someone missing it in the binary stanza. If you have any better ideas for how to render it, feel free to reach out to me.
Spurious completion and hover As I was debugging the Inlay hints, I wanted to do a quick restart of debputy after each fix. Then I would trigger a small change to the document to ensure kate would request an update from debputy to render the Inlay hints with the new code. The full outgoing payloads are sent via the logs to the client, so it was really about minimizing which LSP requests are sent to debputy. Notably, two cases would flood the log:
  • Completion requests. These are triggered by typing anything at all and since I wanted to a change, I could not avoid this. So here it was about making sure there would be nothing to complete, so the result was a small as possible.
  • Hover doc requests. These are triggered by mouse hovering over field, so this was mostly about ensuring my mouse movement did not linger over any field on the way between restarting the LSP server and scrolling the log in kate.
In my infinite wisdom, I chose to make a comment line where I would do the change. I figured it would neuter the completion requests completely and it should not matter if my cursor landed on the comment as there would be no hover docs for comments either. Unfortunately for me, debputy would ignore the fact that it was on a comment line. Instead, it would find the next field after the comment line and try to complete based on that. Normally you do not see this, because the editor correctly identifies that none of the completion suggestions start with a \#, so they are all discarded. But it was pretty annoying for the debugging, so now debputy has been told to explicitly stop these requests early on comment lines.
Hover docs for packages I added a feature in debputy where you can hover over package names in your relationship fields (such as Depends) and debputy will render a small snippet about it based on data from your local APT cache. This doc is then handed to the editor and tagged as markdown provided the editor supports markdown rendering. Both emacs and kate support markdown. However, not all markdown renderings are equal. Notably, emacs's rendering does not reformat the text into paragraphs. In a sense, emacs rendering works a bit like <pre>...</pre> except it does a bit of fancy rendering inside the <pre>...</pre>. On the other hand, kate seems to convert the markdown to HTML and then throw the result into an HTML render engine. Here it is important to remember that not all newlines are equal in markdown. A Foo<newline>Bar is treated as one "paragraph" (<p>...</p>) and the HTML render happily renders this as single line Foo Bar provided there is sufficient width to do so. A couple of extra newlines made wonders for the kate rendering, but I have a feeling this is not going to be the last time the hover docs will need some tweaking for prettification. Feel free to reach out if you spot a weirdly rendered hover doc somewhere.
Making quickfixes available in kate Quickfixes are treated as generic code actions in the LSP specs. Each code action has a "type" (kind in the LSP lingo), which enables the editor to group the actions accordingly or filter by certain types of code actions. The design in the specs leads to the following flow:
  1. The LSP server provides the editor with diagnostics (there are multiple ways to trigger this, so we will keep this part simple).
  2. The editor renders them to the user and the user chooses to interact with one of them.
  3. The interaction makes the editor asks the LSP server, which code actions are available at that location (optionally with filter to only see quickfixes).
  4. The LSP server looks at the provided range and is expected to return the relevant quickfixes here.
This flow is really annoying from a LSP server writer point of view. When you do the diagnostics (in step 1), you tend to already know what the possible quickfixes would be. The LSP spec authors realized this at some point, so there are two features the editor provides to simplify this.
  1. In the editor request for code actions, the editor is expected to provide the diagnostics that they received from the server. Side note: I cannot quite tell if this is optional or required from the spec.
  2. The editor can provide support for remembering a data member in each diagnostic. The server can then store arbitrary information in that member, which they will see again in the code actions request. Again, provided that the editor supports this optional feature.
All the quickfix logic in debputy so far has hinged on both of these two features. As life would have it, kate provides neither of them. Which meant I had to teach debputy to keep track of its diagnostics on its own. The plus side is that makes it easier to support "pull diagnostics" down the line, since it requires a similar feature. Additionally, it also means that quickfixes are now available in more editors. For consistency, debputy logic is now always used rather than relying on the editor support when present. The downside is that I had to spend hours coming up with and debugging a way to find the diagnostics that overlap with the range provided by the editor. The most difficult part was keeping the logic straight and getting the runes correct for it.
Making the quickfixes actually work With all of that, kate would show the quickfixes for diagnostics from debputy and you could use them too. However, they would always apply twice with suboptimal outcome as a result. The LSP spec has multiple ways of defining what need to be changed in response to activating a code action. In debputy, all edits are currently done via the WorkspaceEdit type. It has two ways of defining the changes. Either via changes or documentChanges with documentChanges being the preferred one if both parties support this. I originally read that as I was allowed to provide both and the editor would pick the one it preferred. However, after seeing kate blindly use both when they are present, I reviewed the spec and it does say "The edit should either provide changes or documentChanges", so I think that one is on me. None of the changes in debputy currently require documentChanges, so I went with just using changes for now despite it not being preferred. I cannot figure out the logic of whether an editor supports documentChanges. As I read the notes for this part of the spec, my understanding is that kate does not announce its support for documentChanges but it clearly uses them when present. Therefore, I decided to keep it simple for now until I have time to dig deeper.
Remaining limitations with kate There is one remaining limitation with kate that I have not yet solved. The kate program uses KSyntaxHighlighting for its language detection, which in turn is the basis for which LSP server is assigned to a given document. This engine does not seem to support as complex detection logic as I hoped from it. Concretely, it either works on matching on an extension / a basename (same field for both cases) or mime type. This combined with our habit in Debian to use extension less files like debian/control vs. debian/tests/control or debian/rules or debian/upstream/metadata makes things awkward a best. Concretely, the syntax engine cannot tell debian/control from debian/tests/control as they use the same basename. Fortunately, the syntax is close enough to work for both and debputy is set to use filename based lookups, so this case works well enough. However, for debian/rules and debian/upstream/metadata, my understanding is that if I assign these in the syntax engine as Debian files, these rules will also trigger for any file named foo.rules or bar.metadata. That seems a bit too broad for me, so I have opted out of that for now. The down side is that these files will not work out of the box with kate for now. The current LSP configuration in kate does not recognize makefiles or YAML either. Ideally, we would assign custom languages for the affected Debian files, so we do not steal the ID from other language servers. Notably, kate has a built-in language server for YAML and debputy does nothing for a generic YAML document. However, adding YAML as a supported language for debputy would cause conflict and regressions for users that are already happy with their generic YAML language server from kate. So there are certainly still work to be done. If you are good with KSyntaxHighlighting and know how to solve some of this, I hope you will help me out.
Changes unrelated to kate While I was working on debputy, I also added some other features that I want to mention.

  1. The debputy lint command will now show related context to diagnostic in its terminal report when such information is available and is from the same file as the diagnostic itself (cross file cases are rendered without related information). The related information is typically used to highlight a source of a conflict. As an example, if you use the same field twice in a stanza of debian/control, then debputy will add a diagnostic to the second occurrence. The related information for that diagnostic would provide the position of the first occurrence. This should make it easier to find the source of the conflict in the cases where debputy provides it. Let me know if you are missing it for certain diagnostics.

  2. The diagnostics analysis of debian/control will now identify and flag simple duplicated relations (complex ones like OR relations are ignored for now). Thanks to Matthias Geiger for suggesting the feature and Otto Kek l inen for reporting a false positive that is now fixed.

Closing I am glad I tested with kate to weed out most of these issues in time before the freeze. The Debian freeze will start within a week from now. Since debputy is a part of the toolchain packages it will be frozen from there except for important bug fixes.

19 July 2024

Bits from Debian: New Debian Developers and Maintainers (May and June 2024)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!

24 January 2023

Bits from Debian: New Debian Developers and Maintainers (November and December 2022)

The following contributors got their Debian Developer accounts in the last two months: The following contributors were added as Debian Maintainers in the last two months: Congratulations!