Linux development

Team-XBMC have ported XBMC Media Center software to Linux a couple of years ago, (for OpenGL using the SDL toolkit), this port is almost as feature complete as XBMC for any other platform and it is currently running very well and stable enough for all people to enjoy using it. The long term goal of Team-XBMC is that downloading XBMC for Linux will become a full port of XBMC with all the features and functions that are available on all other XBMC platforms (with the exception of Xbox exclusive functionality such as Trainers, Xbox Game-Save Manager, launching Xbox Games, etc.), so downloading XBMC for Linux will be one version of a multi-platform software.

XBMC is a huge open source project and it takes loads of people working together to maintain it for all platforms, that is why Team-XBMC is always on the lookout for C/C++ programmers to volunteer in assisting us with the development of XBMC. Whether you have contributed to The XBMC Project in the past or not, please consider doing so now.

Note to XBMC end-users! You can help too by downloading XBMC for Linux, testing it, and reporting bugs and issues. Also, spread the word about XBMC for Linux to your friends and family, we are sure they will enjoy it too. XBMC is free and do not contain any spy-ware nor add-ware.

Those of you who are completely unfamiliar with XBMC can get a good overview of the features and functions that XBMC offers for its end-users by reading through the XBMC article on wikipedia.org

What is XBMC and why was it ported to Linux?

For the developers who does not know this; XBMC Media Center (formerly named "XBox Media Center", not to be confused with Microsoft's Windows Media Center Extender for the Xbox) is an award-winning free and open source media player, originally designed to run on the Xbox game-console. The GPL/LGPL licensed source code basically consist of a GUI framework that has been written from scratch by Team-XBMC, this GUI acts as a front-end control interface for several audio/video players designed for specific purposes (and those are loaded when needed as DLLs), the GUI is also the user interface to all of XBMC multimedia handling functions such as databases and sorting, etc.. The XBMC Project, (who's members maintain XBMC source code), is a non-profit open source hobby project that is developed by volunteers in their spare-time without any monetary gain. The team of developers working on XBMC have always encouraged anyone to submit your own source code patches for new features or functions, improve on existing ones, or fix bugs.

Skill requirements and where to start

Proficient in C/C++ programming language, and though not required knowledge of OpenGL and/or multimedia programming is a plus, as well as prior cross-platform or porting development experience. You do not need to have access to an Xbox game-console or any special tools/software in order to take part - XBMC development is well underway on Linux (32-bit Ubuntu for x86).

Where do I start (Linux)?

The recommended Linux development platform is currently 32-bit Ubuntu Desktop (for x86). There is a Kdevelop project file available in our SVN (Subversion revision control system). After you have done a SVN checkout, follow the install guide in the SVN (README.linux) to setup the required packages and so on. Team-XBMC developers opinion is that the best thing to start with is just to take a look through the source code and try to understand how it all fits together. Test things out, find what works and what does not, then try and track down why.

Alternatively, you can download a finished VMware Virtual Machine (VM) and run that in the free VMware Player (or use in VMware Workstation, or VMware Server), this is a little bit old now but can still be usefull to those of you that that absolutly new to developing on Linux. The VM available for download below is based on Ubuntu Desktop (32-bit for x86), and all the prerequisite software is installed (including KDevelop). Performance is not great using this, as there is no 3D hardware acceleration support under a virtual machine, however it should work good enough to get a lot of development tasks done without you having to bother with install of Ubuntu Desktop yourself. Nice is also that you can install/run VMware Player 2.0 and later under Linux as well as Microsoft Windows (including Windows Vista), 32-bit and 64-bit operating-system. The free VMware Player 2.0 and later also enables you to share data seamlessly between the virtual machine and host computer, and also allows you to directly access USB 2.0 devices from within the virtual machine, (experimental support for 2-way Virtual SMP to assign more than a single CPU to a virtual machine is also available for testing purposes).

• Download: VMware Virtual Machine (VM) with Ubuntu Desktop 7.04 and KDevelop (userid/password is: xbmc/xbmc).
  • Besides from KDevelop, additional development tools included are Subcommander, Doxygen, Sysprof, and PowerTop.
    • Note! In order for the PowerTop tool to actually show data, a new kernel needs to be built by yourself.
  • Our thanks goes out to tssgery for creating and hosting this first VM for the XBMC Linux port development effort.

Hardware requirements

• x86-based computer. No other special hardware is required for development, as developers can compile using the "make sdl_2d option" (see README.linux). However for end-users the recommended minimum requirement is a 3D GPU (Graphics Processing Unit) that at least supports Shader Model 3.0 and OpenGL 2.0 (that features 24bpp or 32bpp for 3D hardware-acceleration support, which XBMC GUI need to run smoothly at an acceptable frame-rate). Graphic adapters that support DirectX version 9.0c or later usually meet all of those mentioned requirements, (Team-XBMC recommends NVIDIA GeForce 6150 or later as NVIDIA are currently the manufacturer that offers good device-drivers for Linux (and NVIDIA GeForce 6150 or later supports OpenGL 2.0).

XBMC Linux port FAQ for developers

Can non-Linux developers also help?

XBMC can also be compiled for Win32 (Microsoft Windows) operating-systems with Microsoft Visual Studio, or for Mac OS X 10.5 (Leopard) and Mac OS X 10.4 (Tiger), so even though Team-XBMC will be focusing on the Linux port of XBMC, it will not hurt if some people who prefer and feel comfortable with Microsoft Visual Studio or Eclipse as a development platform also volunteer to help with getting the XBMC for Windows and XBMC for Mac builds up to par with the Linux and Xbox versions of XBMC, this as a preparation for possible future cross-platform versions of XBMC.

• XBMC for Windows port project
  • HOW-TO compile XBMC for Windows from source code
• XBMC for Mac OS X port project
  • HOW-TO compile XBMC for Mac OS X from source code

Why is OpenGL 2.0 needed for XBMC?

OpenGL 2.0 is not really the current minimum requirement to run XBMC for Linux, as in reality XBMC will today run with only OpenGL 1.3 + GLSL support (everything else has fall-backs to be runned in software on the CPU, slower than GPU hardware though), however to be sure to stay future-proof Team-XBMC have decided that the OpenGL 2.0 is the recommended minimum requirement.

Currently OpenGL 2.0 hardware is only needed for:

• Any deinterlacing that is not linear blending (which FFmpeg does in software)
• Video video post-processing filtering (bicubic upscaling, etc.)
• Non-power of two textures for the GUI (using NPOT saves a lot of texture memory)
• Hardware accelerated YUV 2 RGB conversion (actually GLSL is needed for this, and a few GPU hardware implementations as low as OpenGL 1.3 does provide GLSL as an extension. OpenGL 2.0 guarantees availability of GLSL).

In the future OpenGL 2.0 might also be needed for:

• More video post-processing filters to improve visual quality perception.
• Hardware Accelerated Video Decoding (using the GPU hardware to assist with video decoding)

Other tools and resources

Though any other tools or resources are not required they can possibly help in development.

Development Tools

• Doxygen - Source code documentation generator tool.
• Valgrind (for Linux) - a free Linux programming tool for memory debugging, memory leak detection, and profiling.
• Sysprof (for Linux) - a free System-wide Linux Profiler for tracking CPU usage. Sysprof is a sampling CPU profiler for Linux that uses a kernel module to profile the entire system, not just a single application. Sysprof handles shared libraries and applications do not need to be recompiled. In fact they don't even have to be restarted. Just insert the kernel module and start sysprof.

Technical summary of XBMC

The basics

The XBMC code structure uses a fairly modular design (with libraries and DLLs), and we think that there are enough modules/libraries to keep a wide skill-level range of developers busy for a while in the porting of them all. So please, take a look at the source code, then with the help of our To-Do list (see further down in this article) assess where the porting stage is today and think about where and how you can try to help out. Note that we are not planning on completely abandoning the Xbox hardware any time soon - XBMC will be a cross-platform software application, using the same code on multiple hardware platforms, (the 'old' Xbox still have a good amount of years to live we hope).

Detailed technical information

For more details please visit the Development Notes section of this manual.

The XBMC source code

The XBMC source code is in our SVN repository on sourceforge.net. Full instructions for compiling/builing XBMC under Linux is available here:

• HOW-TO compile XBMC for Linux from source code

To-Do list for the XBMC Linux port

This is a To-Do list of things that still need to be done in XBMC for Linux, anyone is more than welcome to help out with any of these tasks:

Cleanup To-Do Tasks

• [CLEANUP - ALWAYS AN ONGOING PROCESS] Document (doxygenize) all of the current/existing code (using doxygen)
• [CLEANUP - ALWAYS AN ONGOING PROCESS] Valgrind debugging (also back-port any fixes to the Xbox and Win32 code branch)

General guidelines

• Code documentation (DocBook, rst, or doxygen for the code documentation steps, preferably the latter, doxygen)
• Self-containment - XBMC should be as little dependent as possible on operating-system and third-party services/deamons/libraries
  • XBMC should for example contain all file-system and network-client (like samba) support built-into the XBMC package
• Modular design - independent modules made up by localized/isolated code libraries without dependencies
  • XBMC should still compile and run if a non-essencial module/library is disabled or removed
• Aim for the GUI/interface to run smoothly on a low spec computer (less than 1Ghz)
  • 3D graphic controller (GPU) will always be required hardware for XBMC so try to utilize the GPU as much as possible
• Avoid harddisk trashing (excess read/write/erase cycles), so no harddrive paging, (utilize RAM memory intead).
  • End-users will be running XBMC and the operating-system on Solid-State memory as a Live CD (LiveDistro) of a USB-key
• Fast load and boot times for end-user perception (other thing can still run/start in the background without the user knowledge)
  • 15-seconds or less from when the end user press the power-button on the computer till he/she can browse the GUI

User-friendliness is next to godlyness

One of Team-XBMC major ongoing goal have always been to make XBMC and its user interface even more intuitive and user-friendly for its end-users, based on the KISS (Keep It Simple Stupid) philosophy. We think that usability is very important for media players like XBMC. Many user interface deciscions are being made by developers who often have little experience in user interface design, in order to improve this, we try to listen to XBMC's end-users for how XBMC is actually being used and how we can improve the user experience. We also aim to do regular overhauls, improving existing features/functions, and scrapping outdated code and features/functions (as "to much stuff" can also be a bad thing).

XBMC as a whole must...

• Be easy to install, set up, and maintain, (so that the end-users do not get fed up with it and quit).
• Have an user interface simple and intuitive enough so that less geek-savvy people are not intimidated by it.
  • Make common usage easy, simple 'Human–Computer Interaction (HCI)', from the viewpoint of an ordinary user.
• Be able to play audio and video files that have been compressed using divx, xvid, etc. directly out-of-the-box
• Be able to and organize audio and video files in an easy and user-friendly way.
• Use standards and be consistant, (the music section can for example not use completely different controls from the video section)
• Perform actions in the GUI with as few 'clicks' as possible
• Require little to none non-GUI configuration (and all such non-GUI config should be via advancedsettings.xml)
  • There is still a little work to be done here, for example RSS-feeds settings need to moved to the GUI
• Look nice.

XBMC developers should always strive to

• Promote open source - XBMC is based on the ideas of FOSS (free open source software), licensed under the GPL and builds partly on other open source projects which we do our best to support. The GPL should be respected at all times. All code should be committed to the XBMC project’s SVN before any public binaries are released.
• Promote the sharing of knowledge and collaboration - Through the use of information sharing tools and practices XBMC is a collaborative environment.
• Understand that development is a team effort - Treating our users as co-developers has proven to be the most effective option for rapid development. Always strive to work as a team at all times. Actively promote discussion on new features and bug fixes, and respect others comments and criticisms with replies in a timely fashion.
• Apply the Law of Diminishing Return - The majority of the effort should be invested in implementing features which have the most benefit and widest general usage by the community.
• Try to make all code, feature, and functions to be platform agnostic - XBMC is a multi-platform software, thus any single platform specific features should be discussed with other team members before implemented. Major features should be developed in a separate branch or committed in small increments so that other members have the opportunity to review the code and comment on it during development.

Mentors

Mentors are developers from Team-XBMC and members of The XBMC Project that have volunteered to assist and mentor non-official XBMC developers in any non-trivial way they can, helping you by checking, commenting and committing your code patches to our SVN source code tree. These mentors have chosen an area they prefer to specialize in, usually this is an area in which they feel they have most interest, knowledge, and expertise in. Initial patches are welcome, and can and will be merged by the team. If you wish to join the team in an official capacity, please let us know.

Linux, Mac OS X, and Windows port mentors and developers

If you are a C/C++ programmer expert, porting specialist or guru and like to volunteer as a 'third-party' mentor and/or developer then please let us know.

Linux Mentors (also lead developers)

• Yuvalt: Everything Linux
• Vulkanr: Everything Linux
• JMarshall: Anything GUI related, Music Library, Video Library, PAPlayer, etc.
• D4rk: OpenGL, other Linux stuff
• Elupus: DllLoader, Mplayer and DVDPlayer
• Spiff: Anything other than DllLoader/MPlayer/DVDPlayer internals.
• monkeyman 67156: Everything Linux
• Topfs2: Everything Linux
• malloc: Everything Linux

Mac OS X Mentors (also lead developers)

• Davilla: Everything Mac OS X
• D4rk: OpenGL, other Mac OS X and Linux stuff
• malloc: Everything Mac OS X and Linux
• Vulkanr: Everything Mac OS X and Linux

Windows Mentors

• WiSo: Everything Win32 (SDL, not DirectX)
• Chadoe (a.k.a. Charly) - Everything Win32 (SDL, not DirectX)
• JMarshall: Anything GUI related, Music Library, Video Library, PAPlayer, etc.

Contact methods

These are developers forums for XBMC development, (programmers/coders only!).
Respect, these are not for posting feature-requests or end-user support requests!

• IRC: #xbmc-linux on freenode official IRC network channel for the XBMC Linux port project
  • (You may also sometimes find developers hanging out at #xbmc on freenode)
• IRC: #xbmc-osx on freenode official IRC network channel for the XBMC Mac OS X port
• XBMC for Linux port Community-Forum for developers only
  • XBMC for Linux port Community-Forum for end-users (unmoderated so far)
• XBMC for Mac OS X port Community-Forum for developers only
  • XBMC for Mac OS X port Community-Forum for end-users (unmoderated so far)
• XBMC for Windows port Community-Forum for developers only
  • XBMC for Windows port Community-Forum for end-users (unmoderated so far)

• HOW-TO submit a patch (where and how to submit source code)