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SponsoringPrograms

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Outreachy

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2016-05


Version 10 (modified by michael, 3 years ago) (diff)

update mentored projects based on GSoC2016

Note: Page to be filled for this round of Outreachy. Please help fill this page, see SponsoringPrograms/Outreachy/2015-05, SponsoringPrograms/Outreachy/2015-12 and SponsoringPrograms/GSoC/2015.

Intern application deadline is March 22, 2016, and internship takes place from May 23 to August 23.

This page is currently still in progress, so more projects should be appearing soon.

Introduction

FFmpeg is the universal multimedia toolkit: a complete, cross-platform solution to record, convert, filter and stream audio and video. It is used by a number of media players (including VLC and MPlayer), video websites (including YouTube and Vimeo), web browsers (including Google Chrome/Chromium and Firefox), social media (including Facebook and Twitter) and countless other software projects in the multimedia field and beyond.

Outreachy is a program that helps underrepresented people to get involved in free and open source software. Through the guidance of mentors, interns gain valuable experience interacting with and coding for open source projects like FFmpeg. Additionally, the project and its users benefit from code created from applicants who often continue contributing as developers.

This is our landing page for the current round of the program, which will formally start in May, 2016. Please also see our Google Summer of Code Page for ideas–most are all also eligible.


Information for Applicants

Getting Started

  1. Get to know FFmpeg. If you are an applicant interested in contributing to FFmpeg, it is recommended to start by subscribing to the ffmpeg-devel mailing-list, visiting our FreeNode IRC channels (#ffmpeg-devel and #ffmpeg although you will find most developers on the first one), and exploring both the codebase and the development workflow. Feel free to contact us if you have any questions.
  1. Find a project. This page will eventually list mentored and un-mentored projects. Mentored projects are well-defined and mentor(s) have already volunteered. Un-mentored projects are additional ideas you may want to consider, but you will have to contact us to find a mentor. You can also propose your own project, if you can think of one that better fits your interest and skill level. If a project description is unclear or you have any questions, please get in touch with its mentor and/or send an email to the program admins at [opw@ffmpeg.org].
  1. Contact us. If you decide on a project, get in touch with the community and let us know. If you want to work on a qualification task, let the respective mentor know so we can avoid duplicated efforts.
  1. Apply. Intern application deadline is March 22, 2016, and internship takes place from May 23 to August 23. See Outreachy: Apply for additional information.

Note: A friendly reminder that while the application to Outreachy is important for you and Outreachy, FFmpeg mentors will not base their decision solely on the Outreachy application. We will judge the applicant based on their abilities in coding, learning the tools, communication skills etc. So please do not worry about your application being perfect for us. Although it is very important to follow Outreachy's application rules so they can pay you.

Qualification Tasks

In order to get accepted you normally have to complete a small qualification task. FFmpeg development can be quite challenging and the qualification task helps us figure out whether you are motivated enough and have the potential to deliver successfully.

Contact us for assistance on selecting a qualification task. You can also browse the FFmpeg Bug Tracker for qualification task ideas. In general qualification tasks should include submitting a patch to the ffmpeg-devel mailing list which passes review and is accepted into the FFmpeg codebase. It will be common for such patches to need multiple iterations of submissions and reviews, so do not wait too long with the first submission!

Contacting FFmpeg

If you have questions or comments feel free to contact us via our mailing list, IRC channel, or e-mail one of the FFmpeg Outreachy admins:

  • Mailing-list: ffmpeg-devel
  • IRC: #ffmpeg-devel on Freenode
  • FFmpeg Outreachy Admin: Kieran Kunhya (kierank in #ffmpeg-devel on Freenode IRC, kieran at kunhya dot com)
  • FFmpeg Outreachy Backup Admins: Michael Niedermayer (michaelni in #ffmpeg-devel on Freenode IRC, michael at niedermayer dot cc), Lou Logan (llogan in #ffmpeg-devel on Freenode IRC, lou at lrcd dot com)

Mentored Projects

This section lists well-defined projects that have one or more available mentors. If you are new to FFmpeg, and have relatively little experience with multimedia, you should favor a mentored project rather than propose your own. Contact the respective mentor(s) to get more information about the project and the requested qualification task.

Create a fuzzing testsuite for FFmpeg

Description: Fuzzing is the process of using random or specially crafted junk input to make programs crash or exploit security vulnerabilities. Many organisations such as Google have fuzzed FFmpeg and found and fixed many issues. The problem is FFmpeg moves so quickly that often new commits expose other problems. We need a way of automatically assessing whether commits have exposed bugs. At the same time we don't want to fuzz parts of the codebase that we know haven't changed because this just wastes CPU cycles.

Expected results:

  • Add an existing specialised fuzzing test application to main repository
  • Create a corpus of small test files that exercise codepaths likely to crash for a selection of decoders or demuxers
  • Build a web interface able to extract information from each commit and run against an appropriate fuzz corpus.

Prerequisites: Knowledge of the command line and program compilation. Knowledge of a web programming language (python, node.js etc). Useful to have C experience.

Qualification Task: Compile and run fffuzz and report and (possibly fix) a crash using zzuf or afl-fuzz.

Mentor: Kieran Kunhya (kierank in #ffmpeg-devel on Freenode IRC, kieran at kunhya dot com)

Backup Mentor: TBC

FFv1 P frame support

Description: FFv1 is one of the most efficient intra-only lossless video codecs. Your work will be to add support for P frames with motion compensation and motion estimation support (the existing motion estimation code in libavcodec can be reused here). Then fine-tune it until the best compression rate is achieved. This will make FFv1 competitive with existing I+P frame lossless codecs like lossless H.264.

Expected results: State of the art P frame support in the FFv1 encoder and decoder implementation.

Prerequisites: C coding skills, basic familiarity with git, solid understanding of video coding especially with motion compensation.

Qualification Task: Implement support for simple P frames without motion compensation in FFv1. That is so that each frame stores the difference to the previous frame.

Alternative Qualification Task: Improve the compression of the existing FFV1 Intra frames, you can change any part of the algorithm but it must be practical, the more improvement you can achieve, the better

Mentor: Michael Niedermayer (michaelni in #ffmpeg-devel on Freenode IRC, michaelni@gmx.at)

Backup mentor: Reynaldo Verdejo (reynaldo in #ffmpeg-devel on Freenode IRC, R Verdejo on g mail)

MPEG-4 Audio Lossless Coding (ALS) encoder

Description: A MPEG-4 ALS decoder was implemented several years ago but an encoder is still missing in the official codebase. A rudimentary encoder has already been written and is available on github. For this project, that encoder is first to be updated to fit into the current codebase of FFmpeg and to be tested for conformance using the reference codec and specifications. Second, the encoder is to be brought through the usual reviewing process to hit the codebase at the end of the project.

Expected results:

  • Update the existing encoder to fit into the current codebase.
  • Ensure conformance of the encoder by verifying using the reference codec and generate a test case for FATE.
  • Ensure the FFmpeg decoder processes all generated files without warnings.
  • Enhance the rudimentary feature set of the encoder.

Prerequisites: C coding skills, basic familiarity with git. A certain interest in audio coding and/or knowledge about the FFmpeg codebase could be beneficial.

Qualification Task: Add floating point support to MPEG-4 ALS decoder

Mentor: Thilo Borgmann (thilo DOT borgmann AT mail DOT de)

Backup Mentor: Paul B Mahol (durandal_1707 in #ffmpeg-devel on Freenode IRC, onemda@gmail.com)

Hardware Acceleration API Software / Tracing Implementation

Hardware Acceleration (hwaccel) API v2

Description: Our support for hardware accelerated decoding basically remains untested. This is in part due to FFmpeg only implementing part of the required steps, and in part since it requires specific operating systems and hardware.

The idea would be to start with a simple stub implementation of an API like e.g. VDPAU that provides only the most core functions. These would then serialize out the function calls and data to allow easy comparison and regression testing. Improvements to this approach are adding basic input validation and replay capability to allow testing regression data against real hardware. This would be similar to what apitrace does for OpenGL.

A further step would be to actually add support for decoding in software, so that full testing including visual inspection is possible without the need for special hardware.

Prerequisites: C coding skills, basic familiarity with git

Qualification Task: Anything related to the hardware acceleration code, though producing first ideas and code pieces for this task would also be reasonable

Mentor: Reimar Doeffinger (reimar in #ffmpeg-devel on Freenode IRC, but since I'm rarely there better email me first: Reimar.Doeffinger [at] gmx.de)

Backup mentor: Reynaldo Verdejo (reynaldo in #ffmpeg-devel on Freenode IRC, R Verdejo on g mail)

MXF Demuxer Improvements

Description: The MXF demuxer needs a proper, compact way to map EssenceContainer ULs to WrappingKind. See ticket #2776 in our bug tracker, and ticket #1916 contains additional relevant information.

Essence in MXF is typically stored in one of two ways: as an audio/video interleave or with each stream in one huge chunk (such as 1 GiB audio followed by 10 GiB video). Previous ways of telling these apart have been technically wrong, but worked and we lack samples demonstrating the contrary.

Expected results: The sample in ticket ticket #2776 should demux correctly. Add a test case in FATE. The solution should grow libavformat by no more than 32 KiB.

Prerequisites: C coding skills, basic familiarity with git. Knowledge of MXF would be useful

Qualification Task: Investigate if there may be a compact way of representing the UL -> WrappingKind mapping specified in the official RP224 Excel document. The tables takes up about half a megabyte verbatim which is unacceptable in a library as large as libavformat.

Mentor: Tomas Haerdin (thardin in #ffmpeg-devel on Freenode IRC, tomas.hardin a codemill.se)

Backup Mentor: Paul B Mahol (durandal_1707 in #ffmpeg-devel on Freenode IRC, onemda@gmail.com)

VDPAU filter

Description: VDPAU is not only about hardware-accelerated decoding but also allows some postprocessing - most notably deinterlacing. Other features of the API include scaling, noise removal, and a sharpening filter. See the VDPAU API documentation for more information on some of the features.

Expected results: Implement a filter that allows usage of the postprocessing features as defined by the VDPAU API. This should particularly include the deinterlacer, and ideally all features should be usable to allow comparing the quality and performance of different hardware and hardware vs. software.

Prerequisites: C coding skills, and you will need hardware that allows VDPAU post-processing.

Qualification Task: TBA

Mentor: Carl Eugen Hoyos (cehoyos in #ffmpeg-devel on Freenode IRC, ce AT hoyos.ws)

Backup Mentor: Reimar Doeffinger (reimar in #ffmpeg-devel on Freenode IRC, Reimar.Doeffinger [at] gmx.de), Thilo Borgmann (thilo DOT borgmann AT mail DOT de)

TrueHD encoder

Description: FFmpeg currently does not support encoding to TrueHD, one of the lossless audio formats used on Bluray discs. A nearly functional Meridian Lossless Packing (MLP) encoder has already been written and is available on github. The MLP codec is the basis for TrueHD. For this project, that encoder is first to be updated to fit into the current codebase of FFmpeg and to be tested for conformance against Surcode's MLP encoder. Second, the encoder is to be updated to implement TrueHD functionality, allowing it to losslessly encode audio to play it on hardware devices capable of TrueHD decoding. Finally, the encoder is to be brought through the usual reviewing process to hit the codebase at the end of the project.

Expected results: a TrueHD encoder that allows to losslessly encode audio to play it on hardware devices capable of TrueHD decoding with a competetive compression rate

Prerequisites: C coding skills, basic familiarity with git

Qualification Task: Update the MLP encoder so that it produces a valid bitstream that can be decoded by FFmpeg without errors to silence. Find out how to validate the generated bitstream besides using FFmpeg.

Mentor: Rostislav Pehlivanov (atomnuker in #ffmpeg-devel on Freenode IRC, atomnuker AT gmail DOT com)

Backup mentor: TBA

Improve Selftest coverage

Description: FFmpeg contains many self-tests, still more code is not tested than tested thus more such tests are needed to ensure regressions and platform specific bugs are quickly detected. Examples of existing self tests can be seen under #ifdef TEST in various files

Expected results: Significantly improve selftest code coverage

Prerequisites: Good C coding skills, basic familiarity with git

Qualification Task: Improve selftest code coverage by at least 1% of two of the main libraries (libavcodec, libavformat, libavdevice, libavfilter, libavutil, libswresample, libswscale) as listed at coverage.ffmpeg.org.

Mentor: Michael Niedermayer (michaelni in #ffmpeg-devel on Freenode IRC, michaelni@gmx.at)

Backup mentor: Reynaldo Verdejo (reynaldo in #ffmpeg-devel on Freenode IRC, R Verdejo on g mail), Thilo Borgmann (thilo DOT borgmann AT mail DOT de)

Improve and Cleanup Swscale

Description: Swscale is the part of FFmpeg responsible for scaling pictures, fields, slices of videos and converting colorspace and pixelformats. The code has a long history and grew alot. It is in need of some cleanup, it has been improved significantly in GSoC 2015, but there is a large number of possibly cleanups and improvments remaining. This is not a simple task. It requires to quickly learn and understand what the existing code does and how it can be restructured to be clearer and more modular without making it slower or otherwise worse in a practically relevant way.

Expected results: A subset of: significantly improve clarity of the code, add features like multithreaded scaling, internal floating point support (swscale is largey integer only). The expected results for this task can also very easily be adjusted during the summer depending on how the work is progressing. Quality code is preferred over quantity!

Prerequisites: Good C coding skills, basic familiarity with git, ability to quickly understand existing code.

Qualification Task: Something that proofs that you understand the existing code and can manipulate it as you need to. A specific possibility would be to move some cases which are handled as cascaded contexts to run as part of the filters from ff_init_filters() wthout using cascaded contexts.

Mentor: Michael Niedermayer (michaelni in #ffmpeg-devel on Freenode IRC, michaelni@gmx.at)

Backup Mentor: Paul B Mahol (durandal_1707 in #ffmpeg-devel on Freenode IRC, onemda@gmail.com)

Motion interpolation in libavfilter

Description: Libavfilter is missing motion estimation and interpolation filters.

Expected results: State of the art frame interpolation in the libavfilter.

Prerequisites: Very good C coding skills, familiarity with git, ability to very quickly understand existing code.

Qualification Task: Basic but working motion estimation filter.

Mentor: Paul B Mahol (durandal_1707 in #ffmpeg-devel on Freenode IRC, onemda@gmail.com)

Backup Mentor: Michael Niedermayer (michaelni in #ffmpeg-devel on Freenode IRC, michaelni@gmx.at)

DICOM support

Description: FFmpeg currently does not support DICOM files although this is a widely used image format that is often passed to patients who have no access to DICOM equipment.

Expected results: Support reading as many features of the format as possible.

Prerequisites: Good C coding skills, basic familiarity with git

Qualification Task: TBA

Mentor: Carl Eugen Hoyos (cehoyos in #ffmpeg-devel on Freenode IRC, ce AT hoyos.ws)

Backup Mentor: Stefano Sabatini (saste in #ffmpeg-devel on Freenode IRC, stefasab@gmail.com)

Unmentored Projects

This is a list of additional projects that interns can consider if a mentored project is unavailable or not within their skill or interests. The intern will have to find a mentor for the project, or of course may also propose their own project.

Your Own Project Idea

Interns can propose their own project. Ideas can also be found by browsing bugs and feature requests on our bug tracker. The work should last the majority of the internship duration, the task must be approved by the developers, and a mentor must be assigned.

Students can discuss an idea in the ffmpeg-devel mailing-list, the #ffmpeg-devel IRC channel, or contact the FFmpeg Outreachy admins for more information.