Tag / Linux Media

  • October 25, 2016 - Reynaldo Verdejo

    The 2016 GStreamer Hackfest & Conference in Berlin

    A few days ago, while on my way back from the GStreamer hackfest and conference combo, I tried to come up with a list of pearls to share here and arrived at a pretty troubling conclusion: there was no easy way to do so. The Hackfest I met Luis (De Bethencourt) a kilometer away from my hotel on a cold Saturday morning on October 8th. By then, I had already figured the only exercise I’d be able to get during my short 4-day stay in Berlin was going to be related to my commute, so I decided to embrace walking. We headed for C-Base as soon as we meet at his hotel’s lobby and arrived 10 minutes later to meet the typical familiar faces from the GStreamer community. So did everything start. The GStreamer developer community, while quite compact, has a surprisingly large number of regulars; people tend to stay around. This is something you hardly […]

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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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  • September 1, 2016 - Javier Martinez Canillas

    Video Decoding with the Exynos Multi-Format Codec & GStreamer

    Exynos SoCs have an IP block known as the Multi-Format Codec (MFC) that allows them to do hardware accelerated video encoding/decoding, and the mainline kernel has a s5p-mfc Video for Linux2 (V4L2) driver that supports the MFC. The s5p-mfc driver is a Memory-to-Memory (M2M) V4L2 driver, it’s called M2M because the kernel moves video buffers from an output queue to a capture queue. The user-space enqueues buffers into the output queue, then the kernel passes these buffers to the MFC where they are converted and put it in the capture queue so the user-space can dequeue them. The GStreamer (gst) multimedia framework supports V4L2 M2M devices, but only for decoders the v4l2videodec element supports. Randy Li is working to also support M2M encoders in GStreamer (v4l2videoenc), but this hasn’t landed in upstream GStreamer yet. This post will explain how to use GStreamer and the Linux mainline kernel to do hardware […]

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  • June 1, 2016 - Mauro Carvalho Chehab

    A Report From the Linux Media Summit in Sunny San Diego

    Linux Media Summit Report 2016 – San Diego The first 2016 Linux Media Summit was recently held on April, 7 in San Diego, California in conjunction with the Embedded Linux Conference. This post will cover some of the major developments that took place during this summit. Linux Media Summit Group Photo CEC Framework Status Update The first version of the Consumer Electronics Control framework is nearing completion, and will likely be submitted for either Kernel 4.7 or 4.8. This framework will allow a lot of useful end-user features including better menu, playback, recording, and tuner control in addition to remote control pass-through. In will also enable better device information discovery and routing. Finally, plans to implement ARC/CDC hotplug support were revealed as well as plans to implement high level protocol constraints (resend, timeout, rate limiting of messages). Whether those constraints can be implemented in the kernel remains to be analyzed, […]

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  • The Linux Kernel Summit Media Workshop was held on October 26, 2015 in Seoul, South Korea. We had 21 attendees from various companies and places in the world gather to discuss the current state of Linux Media and the challenges that need to be overcome to push these technologies into the future. This article will cover the major topics that were discussed during this workshop and the decisions that were made about the direction of this community.   Codec API Improvements Currently, Video4Linux version 2 (V4L2) memory to memory devices uses the Stream API to handle coders/decoders (codecs), but it might be time for us to develop a Frame API to handle newer devices. Stream API The original V4L2 codec API was developed along with the Exynos codec driver. Since the device implements high-level operations in hardware, the resulting API was high-level as well with drivers accepting unprocessed raw streams. […]

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  • April 25, 2015 - Samsung Open Source Group

    Open Source Weekly Wrap-Up: April 19 – 24, 2015

    Samsung Launches GearVRf: an Open Source Virtual Reality Framework GearVRf is a new open source rendering library for application development on VR-supported Android devices. The GearVRf API provides simplified access to the Oculus SDK functionality via the Java Native Interface and the GearVRf native library. This project was launched by Samsung as a collaborative effort that involved the Open Source Group. This blog will feature an article next week that covers the work we put into launching this project. Learn more, or get involved through the Gear VRf Wiki. Daily Wayland & Weston Builds For Ubuntu While Canonical is focusing on Mir for Ubuntu’s display server, other developers are still working on alternatives, such as our very own Bryce Harrington. Bryce has established a daily build archive of Wayland and the reference Weston compositor. This makes it easier than ever before to try out the newest Wayland/Weston code on Ubuntu […]

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