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Changes between Initial Version and Version 1 of ProjectIdeas/2014

03/03/15 12:49:49 (7 years ago)
Antoine Martin

archive the old page


  • ProjectIdeas/2014

    v1 v1  
     1{{{#!div class="box"
     2= Project Ideas =
     4       Xpra is a remote desktop tool providing many exciting features as compared to other open source tools. It is developed with a [/wiki/Source#Statistics mix of Python and C], and works on many platforms. The list below describes Google Summer of Code project ideas, aimed both at improving Xpra and at teaching the students about how a remote desktop solution works.
     6       Xpra is taking part in [https://www.google-melange.com/gsoc/homepage/google/gsoc2014 Google Summer of Code 2014] under the umbrella of the [http://www.x.org/ X.org] organization. Students will therefore be applying to [http://www.x.org/wiki/SummerOfCodeIdeas/ X.org GSoC] after having discussed their project with Xpra. To apply, you need to :
     7- [/wiki/Building download, build] and [/wiki/Usage use Xpra] a little
     8- join the [irc://irc.freenode.net/winswitch IRC channel]
     9- read the [/wiki#Internals existing documentation] to get the best possible understanding of what Xpra is (you will be quizzed on the matter)
     10- contribute at least one patch to the project, that is subsequently committed to the repository
     11- discuss a project idea with the developers, in order to build your own understanding and goals for this project
     12- write the project proposal including several milestones with deliverables and an approximate timeline
     15{{{#!div class="box"
     16== 1) Xorg related improvements: {{{RandR}}}, {{{DPI}}}, {{{DRI3K}}} ==
     18       Xpra acts as an X11 compositor, and uses many different X APIs and features to achieve its purpose. We have run into some limitations related to X11 features.
     19       For example, Xpra has to be able to dynamically adapt the remote (server-side) virtual framebuffer to match the client configuration exactly. Although this mostly works OK using {{{xf86-video-dummy}}} and [/wiki/FakeXinerama libfakeXinerama] (to fake the same number of screens), there is still much room for improvement.
     20       * Better [http://en.wikipedia.org/wiki/RandR RandR] support in the [http://cgit.freedesktop.org/xorg/driver/xf86-video-dummy/ dummy driver] ({{{xf86-video-dummy}}}) to allow us to use any resolution we choose without needing to have it pre-defined in the [/browser/xpra/trunk/src/etc/xpra/xorg.conf xorg.conf] shipped with xpra. The changes may actually need to be applied to the core server and/or the dummy driver.
     21       * DPI issues (should probably be tied to the {{{RandR}}} issue above - though it may also interact with {{{libfakeXinerama}}}): some applications will talk to the X11 server directly to obtain the screen dimensions and calculate their own DPI value. The virtual screen we define for Xpra is not meant to have a fixed "physical" size: it is meant to adapt to what the client specifies and should be changed whenever a new client connects. Because the X11 server assumes that the dummy screen size is fixed, the DPI values calculated by the client applications will vary widely depending on the current screen resolution set at the time the DPI is calculated, causing some ugly rendering problems. The dummy driver needs to support changes to the "physical" screen dimension at runtime (and not just the resolution). '''Note''': this is now mostly solved in #163
     22       * [http://keithp.com/blogs/dri3k_first_steps/ DRI3K] support. Someone interested in the world of X.org may be interested in this project.
     24       '''Difficulty''': hard\\
     25       '''Keywords''': C, X11, X.org
     28{{{#!div class="box"
     29== 2) Wayland ==
     30       With the advent of [http://wayland.freedesktop.org/ Wayland], a modern replacement to X11, the basis of Xpra (the X Composite extension) disappears. Xpra is conceptually an X compositor, and it could be modified to also become a Wayland compositor. This project is about making Xpra Wayland-compatible so that Wayland gets a network "transparency" layer that is efficient with fully open source (aside from the existing Wayland RDP implementation).
     31       Tasks are :
     32           * Understand Wayland and its concepts ("surfaces", input devices, etc)
     33           * Make Xpra behave (optionally and in addition to X11) as a Wayland compositor
     34           * Promote the work towards the Wayland community, and submit it for review
     36           '''Difficulty''': medium/easy\\
     37           '''Keywords''': Wayland, compositor, X.org, X11, network transparency
     40{{{#!div class="box"
     41== 3) Keyboard mapping improvements ==
     42       The applications running on the server need to receive mouse and keyboard input. It is easy to map the client-side mouse-input to mouse events on the server side, but it's more difficult for the keyboard, because the keyboard mapping on the client side can be different from one client to another (US, french, german, ...). What transits over the wires are keycodes (the physical position of the key on the keyboard), and they are translated back to keysyms (the keymap-dependant symbol produced when the key is pressed) on the server side. Xpra uses obsolete X APIs to do this translation work, and often gets it wrong. In addition, running virtual machines with e.g. {{{VirtualBox}}} inside Xpra adds another layer of keyboard translation, and the end result is often wrong.\\
     43       The tasks for this project are:
     44           * Learn and understand the X11 keyboard input system (specifically {{{Xkb}}})
     45           * Re-implement keyboard mapping logic using {{{Xkb}}} instead of core keyboard API (probably using the [http://xkbcommon.org/doc/current/ xkbcommon] library)
     47           '''Difficulty''': hard\\
     48           '''Keywords''': Xkb, X11, input, C
     61Non-Xorg related project ideas:
     64{{{#!div class="box"
     65== 4) Automated problem reports ==
     66       The Xpra client, like any piece of software, has bugs. It sometimes crashes. It's not a big deal: you just have to restart the client, and you'll get your applications back (unless the server crashed also, but it happens less often). However, whenever it crashes, and especially on Win32 platforms, there is very little information that can be sent to the developers to help them fix the bug, and reproducing the crash is not always straightforward. \\
     67       This project is about making Xpra easier to debug. Ideas are :
     68           * Integrate an automated stack trace mechanism
     69           * Generate automatic crash reports, including screenshots if necessary, to enable easy bug reporting for users
     70           * Allow building of the client with debug symbols
     72           '''Difficulty''': medium\\
     73           '''Keywords''': Python, backtrace, automated bug reporting
     76{{{#!div class="box"
     77== 5) Android client support ==
     78       The objective is for Xpra to support as many platforms as possible for the client. An Android client exists but is not completely up-to-date in terms of feature, and its usability is far from perfect. This project consists in improving Android client support, or, alternatively, implement Xpra client support for another mobile platform (be it Linux - Raspberry Pi, Android, or any other OS).\\
     79       The tasks for Android consist in the following:
     80           * Support keyboard
     81           * Support pinch to zoom
     82           * Support video scaling
     83           * Add any required feature for comfortable, seamless remote desktop
     84        The applicant is encouraged to propose implementing support for any other low-power/mobile platform, with an extensive list of tasks to be carried out and prior technical research.
     86            '''Difficulty''': Hard\\
     87            '''Keywords''': Android
     90{{{#!div class="box"
     91== 6) Latency improvements through hardware-accelerated video decoding ==
     92       Remote desktop software is very sensitive to latency. Too high of a latency can kill the user experience. Latency sources are obviously the network, but also and usually more importantly, the video encoding on the server side, the video decoding on the client side, and the video presentation on the client side.\\
     93       We have preliminary support for OpenGL presentation on the client side (doing YUV to RGB conversion and drawing), which helps with latency. However, there is the technical possibility of offloading the video decoding process to the GPU using such APIs as VAAPI (Linux) or DxVA (Windows), possibly both through libva which we already use. This project is about improving latency of Xpra, with the following tasks :
     94           * Offload video decoding to the GPU through libva
     95           * Make this work on Windows clients as well as Linux clients
     96           * Make this work with OpenGL presentation on the client-side
     97           * Do whatever else is necessary to improve latency
     99            '''Difficulty''': medium\\
     100            '''Keywords''': OpenGL, libav, video decoding, Windows, Linux, Python, C
     103{{{#!div class="box"
     104== 7) Encryption ==
     105       At the moment, Xpra can use AES encrypted communication over TCP. It supports password authentication, but the key exchange system is open to MITM attacks. \\
     106       Xpra supports a mode where it connects through an SSH connection. That mode is good, but doesn't answer all needs: it requires an ssh server and each user connecting to the session to have shell access on the system, no matter what application needs to be run.\\
     107       The objective of this project is to implement a secure transport mechanism, based on known good cryptographic algorithms.\\
     108       Tasks are:
     109           * Implement secure key exchange
     110           * Implement correct AES CBC mode
     111           * Assess performance impact in terms of latency, bandwidth, and CPU requirements
     113           '''Difficulty''': Medium, knowledge of good crypto practices\\
     114           '''Keywords''':  (py)crypto, AES
     117{{{#!div class="box"
     118== 8) Win32 server (shadow mode) ==
     120       Xpra's client works on many platforms, but the server is restricted to Linux. This means that Xpra can only be used to remotely access a Linux-based desktop. It would be very interesting to make Xpra's server able to work on a Windows machine. Currently there is preliminary support for this feature but it uses polling which is very inefficient.\\
     121       This project is about improving support for Windows-based server, so that it achieves satisfying performance. Tasks would include:
     122           * Implement screen update detection code so xpra can forward only the parts of the screen that have actually changed (as it does on *nix)
     123           * Implement win32 socket code so "xpra info" can be used on win32 servers
     124           * Rely on benchmarks to assess which improvements to make and
     125        Applicants are required to have some Windows development experience.
     126           '''Difficulty''': Medium\\
     127           '''Keywords''':  Windows named pipes, GDI