Category: Users

  • This article will explain how to use GStreamer to capture Digital Television (DTV) streams; it will focus on terrestrial DTV and ATSC broadcasts in the Silicon Valley area to provide examples, but the principles are the same for every other DTV standard or supported location. If you want to follow the examples, you will at the very least need a Linux machine with GStreamer and v4l-utils, and a DTV capture device. For my ATSC testing setup I use a WinTV-HVR 950Q USB stick (Hauppauge), connected to a Debian desktop computer that runs the latest code for GStreamer and dvbv5-scan from their respective git repositories, both uninstalled. This setup works well for me as a developer but if you simply want to play DTV streams on your machine, the version from your distribution’s binary packages should suffice. A Few Notes on Receiver Setup You’ll need to have your receiver setup properly to capture multi-media content from a radio […]

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  • October 13, 2016 - Mauro Carvalho Chehab

    Finishing the Conversion of Linux Media Documentation to ReST

    This article is part of a series on improvements to Linux Kernel documentation; this article will describe the effort to convert the remaining Linux Media subsystem documentation. The Linux Media Subsystem Documentation Before Kernel 4.8, the Linux Media documentation was splt into the Linux Media Infrastructure userspace API (uAPI), which described the system calls and sysfs devices the media subsystem uses. The conversion of this book was already explained in a previous article from this series, the Media subsystem kernel internal API (kAPI), which described the functions and data structures a media driver should use to implement drivers, some text files describing how to use the kAPI, these are spread inside the Documentation/ directory at the Kernel tree, a set of files that document some V4L drivers under Documentation/video4linux, and a set of files that document some DVB drivers, under Documentation/dvb. Converting the kAPI Book The kAPI book is actually […]

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  • This article is a part of a series that covers improvements that are being made to the Linux Kernel documentation; this article will begin to explain how we handled the conversion of the Linux Media subsystem documentation. The Linux Media Subsystem The Linux Media subsystem is actually a set of subsystems; each subsystem has its own particularities: Video4Linux –  API and core provide functions for video stream capture and output. It also provides support for video codecs, analog TV, AM/FM radio receivers and transmitters and for software digital radio (SDR) receivers and transmitters. Linux DVB – provides support for digital TV. Despite its name, it supports worldwide standards, including DVB, ATSC, ISDB, and CDDB, as well remote controllers and infra-red devices. Media Controller – provides pipeline control and reconfiguration inside the hardware. HDMI CEC – provides support for the HDMI Consumers Electronic Control (CEC): a system to pass remote controller […]

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  • August 3, 2016 - Phil Coval

    How to Boot Tizen on ARTIK

    The fact that Tizen can be run on ARTIK is not the latest breaking news, considering it was previously demonstrated live at the 2015 Tizen Conference. There, the ARTIK project was also explained as an IoT platform of choice. Since then, ARTIK has become a new Tizen reference device, so here are a couple of hints that will help you test upcoming Tizen release on this hardware. First let me point out that Tizen’s wiki has a special ARTIK category, where you’ll find ongoing documentation efforts, you’ll want to bookmark this page. In this article, I will provide a deeper explanation of how to use the bleeding edge version of Tizen:3.0:Common on ARTIK10, and how to start working on this platform. As explained in my previous Yocto/meta-artik article, I suggest you avoid using the eMMC for development purposes; for this article I will boot the ARTIK from an SDcard. In […]

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  • Kaffeine version 2.0.4 has been released today, substantially improving its already excellent Digital TV (DTV) support! Update: tarball is now available at: While version 2.0.4 was meant to solve several bugs reported via the project’s bug tracker, it offers a lot more: DVB-S/S2 Kaffeine improvements Kaffeine now supports the ability to select the Low Noise Blockdown feedhorn (LNBf) among a list of other LNB features used on Digital TV. This list comes from libdvbv5, which provides the backend to setup a satellite configuration. Other Network Information Table Scans Digital TV relies on physical transponders to transmit a signal, and each transponder can carry multiple channels. There’s a special table in the MPEG transport stream that’s responsible for listing the other transponders associated with a given transmission that belong to the same network provider. This table is called the Network Information Table (NIT). Sometimes, there are multiple tables on an […]

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  • Ubuntu guest sessions are a convenient way to let someone use your system with limited access to the network, file system, and other system functions without the ability to save data. The /usr/lib/lightdm/lightdm-guest-session binary handles guest sessions, and several services which are deemed unnecessary for a guest user are disabled. Refer to /usr/share/lightdm/guest-session/ for details on what is enabled. When guest session starts, you will see a warning that any data saved will be lost as shown below. A temporary home directory is created under /tmp which will be deleted when guest session ends via logout, or a reboot. When the guest session is active, you will see a directory guest-xxxx as in the e.g /tmp/guest-6vqi30. So what do you do if a guest session ends unexpectedly?! I recently logged out of a guest session by mistake and had to scramble to recover my son’s school essay which was ready to be submitted. […]

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  • June 3, 2016 - Mauro Carvalho Chehab

    Watching Digital TV Via Kaffeine

    Kaffeine is a media player application that uses the KDE libraries. As part of my work maintaining the Linux Kernel media subsystem I needed some tools to test whether or not the digital TV core support works properly and to test Linux drivers for new devices. So, I’ve recently been working to improve Kaffeine to offer the necessary features for such tests. As part of this, I recently created a major Kaffeine version (2.0) that uses the latest version of KF5 (KDE Frameworks 5), and to use Qt5 library. I also started helping with upstream Kaffeine maintenance. UPDATE: Added instructions for Arch Linux How to Install Kaffeine Installing Kaffeine is easy. If you run openSUSE Tumbleweed, you can find an up-to-date package with the latest state of development tree in the KDE:Unstable:Extra repository. So, to use the newest version of Kaffeine, all you need to do is to run:


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  • August 31, 2015 - Bryce Harrington

    Simulating Middle-Mouse Paste on Touchpads

    When did you first run into a computer with a mouse? How many buttons did it have? Most UNIX-like operating systems provide two separate copy buffers; the first provides the standard copy and past functionality everyone knows and loves (Ctrl + C, Ctrl +V), while the second allows you to paste selected text directly. The use of this secondary buffer has been dependent largely on mouse design for the last few decades, and as the hardware has changed, so has the usage of this copy buffer. First, A Little History I was familiar with the original Mac mouses with their curious single button, but the first mouse-based computer I used was a Sun workstation in the early 90’s while I was in college. It had THREE buttons; a proper mouse! The left button selected things, the right brought up context menus, and the middle button pasted from the secondary copy […]

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  • August 10, 2015 - Brian Warner

    Tizen Has Serious Momentum in India

    I was fortunate enough to attend the third Tizen Developer Summit, hosted this year in Bengaluru, India. What a great experience! As you might be aware, I recently joined Samsung from the Linux Foundation (more on this in the future), where I was the manager of the Tizen project. I’ve been involved in every Tizen event since the beginning, but there was something special about this one that felt like a milestone had been passed, and it wasen’t just because of the million Samsung Z1 smartphones that have been sold since launch. People are Flocking to Tizen I wasn’t surprised simply by the size of the event; there were more than one thousand attendees at what’s typically Tizen’s smaller event every year. Nor was I surprised by the 500 plus people that signed up for the Tizen DevLab, 2.5 times more people than we had seats for. Although it is […]

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