Fix “unmet dependency” issue for pulseaudio in KXStudio (and others)

18 Aug

[note: this tip will apply to other “unmet dependency” situations, but definitely not all of them]

If you are a user of the KXStudio repos, and use an environment rid of pulseaudio, you probably were disappointed to see that Firefox recently stopped supporting the ALSA backend. The issue came back recently for me, as Firefox 55 does not seem to have been compiled with the --enable-alsa.

If you are having the “unmet dependency” issue when trying to install pulseaudio-module-jack with apt-get, it might be an issue with conflicting package versions from different sources.

The following packages have unmet dependencies.
pulseaudio-module-jack : Depends: pulseaudio but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

If you use aptitude instead, you will get some more info:

The following packages have unmet dependencies:
pulseaudio : Depends: libpulse0 (= 1:4.0-0ubuntu11.1) but 1:4.0-0ubuntu11.1+kxstudio1 is installed.

The culprit seems to be libpulse0 here. In other cases, you might have to follow the thread of unmet dependencies down until you get to the bottom of it (as in the case of Wine in another similar situation I had).

You can see that the conflicting versions of the package are basically the same, so using one over the other should not cause issues. The problem here is that the KXStudio version has an extra long name to identify its source. You can now identify the different versions of the package that are available:

apt-cache policy libpulse0

… and force the installation of a specific version:

sudo apt-get install libpulse0=1:4.0-0ubuntu11.1

After that, you should be able to install pulseaudio-module-jack without running into any issue.

Remember to start PulseAudio in Cadence so sound comes out of Firefox (no need to restart anything).

Two Crowd Supply projects worth supporting

24 Mar

Crowd Supply is a crowdfunding website that does things differently. Projects hosted on it are usually directed at hackers, and they promote businesses that try to do things differently (I would describe it as “progressive” in a sense). Products can also keep being purchased after the funding target is reached, which also makes it a kind of online shop for cool hardware.

I wanted to tell you about two projects that I consider are worth supporting, mainly because of their links to the Free Software movement (both of them expect to be certified by the stringent FSF label “Respects Your Freedom“, or RYF), but also because they are great projects.

GnuBee: Personal Cloud 1

GnuBee is a personal cloud NAS device that is currently being funded.

From the project page:

The GnuBee Personal Cloud 1 (GB-PC1) is a network-attached storage (NAS) device specifically engineered to run free, libre, open source software (FLOSS). The GB-PC1 has all the functionality of any commercial, proprietary NAS, but at a much lower cost and with the transparency, reliability, and accessibility advantages that come with using FLOSS.


We designed the GnuBee Personal Cloud 1 with the Free Software Foundation’s Respects Your Freedom (RYF) certification in mind and have already initiated the application process with FSF.

In short, we expect the units shipped to backers to be 100% free of binary blobs. Below is a longer explanation.

In the current prototype, there is exactly one binary blob, but we have a clear path to removing it and plan to remove it before shipping the first production units. In particular, the binary blob is for the ASM1061 PCI-to-SATA bridge. As it turns out, a libre kernel driver for this particular chip was mainlined since our original board design, so it should simply be a matter of removing the associated SPI NOR flash chip and using the kernel driver directly to control the PCI-to-SATA bridge.

Even though we think we’d still qualify for RYF certification if we left the design as is (there’s an exception for secondary embedded processors), we nonetheless fully intend to remove this blob and the associated SPI NOR flash chip.

Unfortunately, I can’t afford this one currently, but I would not have hesitated in different circumstances.

Earth-friendly EOMA68 Computing Devices

EOMA68 has already reached its target, but you can currently purchase products.

The goal of this project is to introduce the idea of being ethically responsible about both the ecological and the financial resources required to design, manufacture, acquire and maintain our personal computing devices. This campaign therefore introduces the world’s first devices built around the EOMA68 standard, a freely-accessible royalty-free, unencumbered hardware standard formulated and tested over the last five years around the ultra-simple philosophy of “just plug it in: it will work.”

  • Truly Free: Everything is freely licensed
  • Modular: Use the same Computer Card across many devices
  • Money-saving: Upgrade by replacing Computer Cards, not the whole device
  • Long-lived: Designed to be relevant and useful for at least a decade, if not longer
  • Ecologically Responsible: Keeps parts out of landfill by repurposing them

The campaign offers a number of products, including different cards sporting different distros (the Libre Tea card being the one aiming at getting the RYF certification), a micro desktop housing, a printable laptop housing, and more parts for tinkering.

I supported this one by buying myself a Libre Tea card and a micro desktop housing, which I am really excited about. And to tell you the truth, I am already happy with my contribution because even just the updates are truly fascinating reads. I am very far from understanding all of the technical jargon, but the way they are written, the anecdotes that are part of the whole development and production process, and the amazing transparency that Luke Kenneth Casson Leighton offers make it a very enjoyable story to follow.

An alternative to Facebook events

7 Dec

After leaving Facebook, you realise how much people rely on it to organise events. Some organisations and even administrations actually only use Facebook to publicise their events, and people have to have an account to be able to RSVP, or even have a look at the detailed information.


The pleasures of browsing a Facebook event when not signed up. Interestingly, the mobile view shows even less than the desktop website: not even a description of the event.

I thought I’d ask and look around for an alternative that people could use. Heck, even my local council advertises their events mostly through Facebook, how inclusive is that.

Ideally, my alternative event hosting would:

  • not require an account to RSVP or browse the information;
  • be free of charge;
  • be based on Free or Open Source software;
  • be respectful of privacy;
  • allow to export the event in different formats to add to calendars;
  • be easy to connect to Facebook.

The reality is that people still love the convenience of having all their events centralised in their Facebook, which means that if I am to convince some people to use a different service / platform, it will have to be nicely hooked up to Facebook so they don’t have to do twice as much work.

Sadly, the social network I am currently using (Diaspora, part of the Federation) does not have an event element to it. However, I used it to ask the community if they had ideas.

Some people recommended software like OpenSondage, Framadate (based on OpenSondage), and Dudle. Unfortunately, those are only enough to figure out what is the best time to schedule an event, as opposed to a fully-fledged event manager (where people see a description with a picture, find times and the address, can RSVP and share…).

I was also recommended to use ownCloud or Nextcloud to create an event with the calendar app. That is not enough, as it is not possible to advertise the event publicly – only through email. However, Framasoft based their software Framagenda on it, adding some functionalities like sharing the event by public link – but I could only figure out how to make a whole calendar public. It seems like the differences with the Nextcloud calendar element are minor.

Communecter is a great tool that allows to build a network between citizens, local councils, businesses and organisations. It looks very useful but is more directed towards organising and communicating at the local level, to foster inclusion  and involvement in the community. Not quite the simple event-creating tool I am looking for.

Open Event is Free Software (GPL-3.0) with several components to create events that follow a standard format and publish them to the web with a website generator, or to Android with an app generator; another component allows organisers to self-host a fully-fledged event manager that supports venues, programs and invitations. This is a very promising piece of software, and there is a live implementation at, but I could not register an account in order to test the event creation. It is definitely a project I will closely follow as it seems it is the closest to my requirements, but it seems it needs some more work to be usable on the demonstration website (server error when creating an account, 404 when trying to get a free ticket to an event, missing “how it works” page…). Their standardised format also makes it a great candidate for a potential integration in other Free Software projects like Diaspora.

Another very promising piece of Free Software that allows you to self-host is Attendize (AAL). It is already completely functional as a feature-full event management system (messaging, stats, ticketing and payment…), and is also very beautiful. There is a demonstration backend but it is only designed to test the software, which makes it less likely to replace an event manager that you simply need to sign up to. However, the software is very advanced and fits most of my requirements, so it is definitely something I would look into self-hosting.

Finally, Eventbrite is the obvious alternative that ticks most of the boxes. It is free of charge for free events, but their codebase is not entirely released as Free or Open Source software, although the company seems active on different FLOSS projects (see their GitHub account). They work hard on providing a good API to integrate their services to other apps and websites, which makes it super easy for Facebook users to have their event on both platforms.

In conclusion:

  • If you are ready to self-host, go with Attendize: it is Free Software and seems to do everything you might need it to as far as managing events goes. Also keep an eye out for developments in Open Event.
  • If you are advertising your events on Facebook but want to make them available to all, please create them on something like Eventbrite. They have a one-click Facebook publishing button that will make life easier, and you won’t coerce people into (re-)creating a Facebook account.

Do you know of other alternatives that would match the requirements?





Remove DRMs from Kobo’s KEPUB format

1 Nov

Kobo decided to go the proprietary Digital Restriction Management (DRM) way by providing some ebooks bought on their platform in their in-house Kepub format. This means that they can only be read on a Kobo device.

You might have noticed that, when trying to copy an ebook from your Kobo device to your desktop Calibre library, it tells you it can’t do that because the book is “virtual”.

You can actually remove the DRMs from that format by using a plugin called Obok, part of the great DeDRM toolbox provided by Apprentice Harper.

  1. Download the latest file from GitHub;
  2. Open Calibre (if you don’t have this amazing ebook management app already, install it);
  3. Install the plugin: `Preferences > Plugins > Load plugin from file`;
  4. Use the Obok plugin with your device plugged in: select the problematic Kepub ebook(s) and let it do its magic. You can now copy the ebook to your library without those pesky DRMs!

Learn more about the Kepub format on

This was tested with Calibre 2.71, Obok DeDRM 6.5.3 and a Kobo Touch with its software at version 3.19.5761.

Fix PGP error NO_PUBKEY when apt-get updating

28 Oct

It is common to find that a  sudo apt-get update does not do a clean job because of a couple of missing public keys. You might get something of the type:

W: GPG error: <a href=""></a> trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F

Usually, it is possible to directly fetch the missing public key from a popular key server like Ubuntu’s:

sudo apt-key adv --keyserver --recv-keys PUBKEY

… where PUBKEY is replaced by the right identifier in your warning message.

That is usually enough and concludes with gpg: Total number processed: 1

However, if the key is not found on the server, you might have to look for it yourself. For example, in the case of the following error:

W: GPG error:  Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F2AA0B1E5EF8303B

… the missing key was not available on the Ubuntu key server. I had to first check what exactly the problematic source’s URL looked like, which you can do by either using your distribution’s updater’s GUI (for example, Muon Update Manager > More… > Advanced … > Configure software sources), or by finding it in /etc/apt/sources.list or /etc/apt/sources.list.d/. In my case, the URL was, which is where I navigated to in my Internet browser to find a Release.key file.

Once you have downloaded that key, you can use the following command to add it to your keyring:

sudo apt-key add Downloads/Release.key

(Make sure you replace Downloads/Release.key with the right path/name.)

Now, you should be able to re-run sudo apt-get update and not run into any warning!

Add missing icons in Ring client

14 Sep

You might have noticed that your Ring desktop client (in my case, the ring package for an Ubuntu 14.04-based distro, version 20160908.1.07d3d92~dfsg1-1 at the time of writing, launched with the gnome-ring command) is missing some icons and shows a red “forbidden” sign instead.

Missing icons in Ring client

Missing icons in Ring client

I fixed that by simply installing a missing dependency called gnome-icon-theme-symbolic. You can do that by executing the following command in a terminal:

sudo apt-get install gnome-icon-theme-symbolic

Close and re-launch the client and the icons should be restored.

Fix two conflicting versions of Keybase

8 Sep

Not having updated keybase in a while (since 0.8.23!…), I ran into an issue after trying to get the latest version (1.0.17) as described on the website: an apt-cache policy keybase would tell me that I had the most recent version installed, whereas running keybase version would return the older one.

The problem is that keybase went from Node.js to Go, and the install method changed. The older version I had installed created a binary in usr/local/bin whereas the new version installed it in usr/bin.

You can see if that is your case by running the two following commands:

/usr/bin/keybase version
/usr/local/bin/keybase version

They should return different versions.

To fix that, you need to uninstall the older version with the following command:

sudo npm uninstall -g keybase

Then, run run_keybase and you should be good!

Install HWSD Viewer on an Ubuntu 14.04-based system

17 Aug

The Harmonized World Soil Database (HWSD) is a 30 arc-second raster database put together by a consortium of organisations: FAO, CAS, IIASA, ISRIC and JRC. It is a monumental collection of data about soil from all around the globe, and is therefore an important tool for researchers.

You can download the raw data or  visualise it on ISRIC’s online viewer, but there is a (closed-source) viewer app specially created to visualise, browse and query the data offline, the “HWSD Viewer”, which unfortunately was only developed for Windows.

To make the viewer work on and Ubuntu 14.04-based system (like KXStudio 14.04, but probably many other OS), you need to:

  1. Make sure you have Wine installed;
  2. Install the viewer, using the binary accessible from this FAO page;
  3. Install the missing runtime libraries thanks to Winetricks, with the following command:
winetricks jet40 mdac28

That should sort you out!

Specifically, what the Winetricks command resolves is:

  • The error message “This setup does not support installing on this operating system.” when trying to install MDAC from the Microsoft website;
  • The error message “Provider cannot be found. It may not be properly installed.” when the software realises Jet40 is not available.

HWSD viewer






Multi-rate HEVC with x265 for adaptive HTTP streaming

15 Aug

Another in-depth look into multi-rate video encoding by my friend Damien Schroeder.


Version 2.0 of x265 has recently been tagged. It has been more than two years of work since version 1.0. Since then, HEVC has become more visible with wide adoption on devices and in software. From a streaming perspective, adaptive HTTP streaming is now the most common streaming technology to watch live or on-demand content on the web, for example with the DASH standard.

Remember, adaptive HTTP streaming requires a video to be encoded at different representations, that is, different qualities, which is generally achieved by encoding the same video at different (spatial) resolutions and different signal qualities. Depending on the encoder and on the encoding mode, the signal quality can be tuned by varying the quantization parameter (QP), or varying the target bitrate when using rate-control. In the case of x265, the so-called constant rate factor (CRF) can also be used to tune the quality of the…

View original post 1,183 more words vous emprisonne en rendant la suppression de compte fastidieuse

5 Jul

J’ai récemment créé un compte sur afin de télécharger quelques ouvrages en format EPUB, sans DRM (il y a quelques titres disponibles dans leur catalogue). Malheureusement, comme beaucoup, je n’ai pas lu les conditions générales de vente avant de faire ça.

En effet, après avoir réalisé que mon compte n’allait pas m’être d’une grande utilité, j’ai décidé de le supprimer (j’essaie de conserver une liste des comptes que j’ai créés sur Internet, et de les supprimer rapidement s’ils ne vont plus (ou peu) m’être utile dans le futur). Quelle n’a pas été ma surprise quand j’ai vu qu’ils demandent aux utilisateurs de leur envoyer une copie d’une carte d’identité ou d’un passeport pour supprimer votre compte et vos données de leurs serveurs. (Voir l’article 14 de cette section ou l’explication dans la page d’aide dédiée.)

J’ai horreur de ce genre de pratiques, qui à l’évidence existent seulement afin de rendre extrêmement difficile la suppression d’un compte, pour que vous décidiez au final d’y rester, contre votre grès. Les conditions générales de vente stipulent que cela est conforme à la « réglementation en vigueur » mais il me semble que cela ne s’applique pas nécessairement à la simple suppression d’un compte en ligne.

Voilà ce qui m’a été dit lorsque j’ai demandé la suppression de mon compte par e-mail :

Conformément à la réglementation en vigueur, votre demande de clôture doit être signée et accompagnée de la photocopie de votre pièce d’identité portant votre signature.

Merci également de nous préciser une adresse postale pour la réception de votre réponse qui arrivera sous un délai maximum de 2 mois.

Quelle pratique d’un autre temps ! Je crée un compte en deux seconde sur leur site, puis pour le supprimer je dois leur écrire une lettre, leur fournir une pièce d’identité et attendre qu’ils me disent si ça leur plaît par voie postale ??

La démarche de désinscription est décrite sur plusieurs sites, dont et Des commentaires indiquent qu’ils conservent également des données après la suppression, et que c’est une des seules entreprises à exiger une pièce d’identité. Est également justement évoquée le risque que vos documents d’identité soient volés en chemin.

Mon conseil : ne créez pas de compte sur, et si vous en avez déjà un et qu’il ne vous sert pas, supprimez-le en précisant que ces pratiques sont abusives.

Mise à jour (2016-07-11) : après m’être plaint de la difficulté de la démarche, et avoir demandé que l’on me communique la « réglementation en vigueur » à laquelle ils font référence, j’ai reçu un e-mail du service client pour me notifier de la suppression / désactivation (les deux termes sont utilisés de façon inconsistante à différents endroits) de mon compte, malgré le fait que je ne leur ai pas envoyé les documents d’identité demandés. Preuve selon moi qu’ils n’en ont pas vraiment besoin, et que c’est uniquement destiné à vous garder contre votre grès.