Small FFmpeg Tasks: Difference between revisions

From MultimediaWiki
Jump to navigation Jump to search
No edit summary
(remove Implemented stuff in FFmpeg)
 
(198 intermediate revisions by 26 users not shown)
Line 3: Line 3:
* Someone who wishes to qualify for one of FFmpeg's coveted [[FFmpeg Summer Of Code|Summer of Code]] project slots
* Someone who wishes to qualify for one of FFmpeg's coveted [[FFmpeg Summer Of Code|Summer of Code]] project slots
* An existing FFmpeg developer who has been away from the project for a while and needs a smaller task as motivation for re-learning the codebase
* An existing FFmpeg developer who has been away from the project for a while and needs a smaller task as motivation for re-learning the codebase
For other tasks of varying difficulty, see the [[Interesting Patches]] page.


'''If you would like to work on one of these tasks''', please take these steps:
'''If you would like to work on one of these tasks''', please take these steps:
* Subscribe to the [https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel FFmpeg development mailing list] and indicate your interest
* Subscribe to the [https://lists.ffmpeg.org/mailman/listinfo/ffmpeg-devel FFmpeg development mailing list] and indicate your interest
* Ask [[User:Multimedia Mike|Multimedia Mike]] for a Wiki account so you can claim your task on this Wiki
* Ask [[User:Multimedia Mike|Multimedia Mike]] for a Wiki account so you can claim your task on this Wiki


'''If you would like to add to this list''', please be prepared to explain some useful details about the task. Excessively vague tasks with no supporting details will be ruthlessly deleted.
'''If you would like to add to this list''', please be prepared to explain some useful details about the task. Excessively vague tasks with no supporting details will be ruthlessly deleted.
The FFmpeg project always needs people to do the following tasks:
#Review bugs on the [https://ffmpeg.org/trac/ffmpeg/report/1 FFmpeg bug tracker]
##verifying bugreports are complete with 'ffmpeg -i' output
##making sure samples are mirrored/available
##verifying bugs against current git master
#Review patches posted to ffmpeg-devel mailing list
##also test to make sure they compile against git master and dont break 'make fate' / compilation
#Review documentation and update examples in documentation.
##updating and adding more information to the howto and api documents
##make a guide how to embed ffmpeg into various programming languages, be it c++, java, mono, c#, etc
== Programming Tasks ==


=== Finish up a previous incomplete SoC project ===
=== Finish up a previous incomplete SoC project ===


Several SoC projects from previous years have not yet made it into FFmpeg. Taking any of them and finishing them up to the point that they can be included should make for a good qualification task. Check out the [[FFmpeg Summer Of Code]] overview page and look for the unfinished projects, like AMR-NB, Dirac, TS muxer, JPEG 2000.
Several SoC projects from previous years have not yet made it into FFmpeg. Taking any of them and finishing them up to the point that they can be included should make for a good qualification task. Check out the [[FFmpeg Summer Of Code]] overview page and look for the unfinished projects, like the TS muxer.
 
=== Add code to validate get_buffer usage of decoders ===
Change the default_get_buffer etc. functions to enforce the minimum guarantees the decoder requests.
E.g. if a decoder does not set FF_BUFFER_HINTS_READABLE, return a buffer without read permissions (using e.g. mprotect).
If the decoder does not use reget_buffer, always return a buffer initialized with random data.
If the decoder does not set FF_BUFFER_HINTS_PRESERVE, always destroy the buffer contents as soon as possible.
Make reget_buffer always fail if FF_BUFFER_HINTS_REUSABLE was not used.
Probably more things that could be done.
 
=== Port missing demuxers from MPlayer ===
MPlayer supports a few container formats in libmpdemux that are not yet present in libavformat. Porting them over and gettting them relicensed as LGPL or reimplementing them from scratch should make reasonable small tasks.
 
# TiVo --
# SL support for MPEG-TS (anyone got samples?)
# MNG -- ''Paul B Mahol is working on this''
 
=== M95 Playback System ===
This task is to implement a playback subsystem for [[M95]] files. This will entail writing a new file demuxer and video decoder (the audio is already uncompressed), both of which should be fairly easy by FFmpeg standards. [[M95|The M95 page]] contains the specs necessary to complete this task and points to downloadable samples.
 
=== BRP Playback System ===
This task is to implement a playback subsystem for [[BRP]] files. This will entail writing a new file demuxer as well as a video decoder that can handle at least 2 variations of format data. Further, write an audio decoder for the custom DPCM format in the file. All of these tasks are considered fairly easy by FFmpeg standards. [[BRP|The BRP page]] contains the specs necessary to complete this task and points to downloadable samples for both known variations.
 
=== 16-bit VQA Video Decoder ===
Westwood [[VQA]] files are already supported. However, there are three variations of its custom video codec, only the first two of which are supported. This task involves implementing support for the third variation. Visit the VQA samples repository: http://samples.multimedia.cx/game-formats/vqa/ -- The files in the directories Tiberian Sun VQAs/, bladerunner/, and dune2000/ use the 3rd variation of this codec. The [[VQA|VQA page]] should link to all the details you need to support this format.
 
Discussion/patch:
http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/89902/focus=90433
http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/173307/focus=173308
 
=== Apple RPZA encoder ===
A patch was once sent to the ffmpeg-devel mailing list to include an encoder for the [[Apple RPZA]] video codec. That code can be found on the "[[Interesting Patches]]" page. This qualification task involves applying that patch so that it can compile with current HEAD and then cleaning it up per the standards of the project. Engage the mailing list to learn more about what to do.
 
=== QuickTime Edit List Support ===
Implement edit list support in the QuickTime demuxer (libavformat/mov.c). This involves parsing the 'elst' atom in a QuickTime file. For a demonstration of how this is a problem, download the file menace00.mov from http://samples.mplayerhq.hu/mov/editlist/ and play it with ffplay or transcode it with ffmpeg. Notice that the audio and video are ever so slightly out of sync. Proper edit list support will solve that. Other samples in that directory also presumably exhibit edit list-related bugs. The [http://xine.cvs.sourceforge.net/xine/xine-lib/src/demuxers/demux_qt.c?view=markup Xine demuxer] has support for this, it might be useful for hints.
 
(patch was submitted to ffmpeg-devel , around 14 March 2009)
 
=== merge all fixed point decoders back into libavcodec ===
http://git.rockbox.org/?p=rockbox.git;a=tree;f=lib/rbcodec/codecs Rockbox's fixed-point decoders are based on decoders from libavcodec.
 
=== flip flag for upside-down codecs ===
 
<pre>about the flip, a patch that decodes images fliped when
codec_tag == ff_get_fourcc("GEOX") is welcome.
its a metter of 2lines manipulating data/linesize of imgages after
get_buffer() or something similar
[...]
--
Michael    GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
</pre>
more info:
http://ffmpeg.org/trac/ffmpeg/ticket/317
 
=== support for [[YCoCg]]/RGB colorspace in FFV1 ===
Add support for [[YCoCg]] and [[RGB]] encoded sources for the [[FFV1]] codec
 
This would add a free lossless intra-frame RGB codec for all supported platforms (most important OS X + Windows) which is often asked for video editing in video forums (e.g. slashcam.de)
 
=== [[IFF#ANIM|IFF ANIM]] decoder ===
Modify libavformat/iff.c to handle this chunk and write a decoder for the format. The wiki page at [[IFF#ANIM|IFF ANIM]] has links to more information and source code. Samples can be found at http://www-user.tu-chemnitz.de/~womar/projects/iffanim/iffanim_samplepack.zip .
 


=== Generic Colorspace system ===
This task involves adding support more than 8 bits per component (Y on 10 bits, U on 10 bits, V on 10 bits for example)
and generic simple conversion to other colorspaces.


''Does this have to do with revising FFmpeg's infrastructure? If so, then it doesn't feel like a qualification task. If it's something simpler, then the vague description does not convey that simplicity. Please expound.'' --[[User:Multimedia Mike|Multimedia Mike]] 12:56, 25 February 2008 (EST)
=== port missing decoders/demuxers from other open source projects. ===


''I don't think so, extending PixFmt to extended structure with finegrained description like depth, range values, colorspace, sample period, and write generic simple conversion from all formats to all others, like suggested by Michael on the mailing list. Conversion routine can be a good qualification task for video encoders/decoders. What do you think ?
http://www.mega-nerd.com/libsndfile/#Features
--[[User:Bcoudurier|Baptiste Coudurier]] 00:30, 29 February 2008 (EST)
GNU Octave 2.0 MAT4
GNU Octave 2.1 MAT5
Designer II SD2
samples are here: http://www.mega-nerd.com/tmp/SoundFileCollection-20050711-0902.tgz


=== Make the SoC dts encoder multichannel capable ===
http://www.hawksoft.com/hawkvoice/
Here is a skeleton for a dts encoder http://svn.mplayerhq.hu/soc/dcaenc/, currently it can only encode stereo streams.
HVDI_VOICE_DATA- packet
The task is to extend it to support 5.1 channels also.
[[GSM]]
LPC
CELP
LPC10


Specs and info can be found here:
http://sourceforge.net/projects/vgmstream
http://wiki.multimedia.cx/index.php?title=DTS
150+ formats: http://vgmstream.svn.sourceforge.net/viewvc/vgmstream/readme.txt


=== GIF LZW Encoder and extend Encoder and Decoder to support Animated GIFs ===
http://www.imagemagick.org
http://www.graphicsmagick.org/formats.html
many image formats not supported yet.


Lzw encoder is already used for TIFF, it must be extended to support GIF flavor.
http://gpac.sourceforge.net/
[[MPEG-4 BIFS]]
3GPP DIMS
[[LASeR]]
SAF
SVG
[[Synchronized Multimedia Integration Language|SMIL]]
VRML
X3D
XMT


=== Support PB frame mode for H.263i ===
http://adplug.sourceforge.net/
Details are in the issue tracker: http://roundup.mplayerhq.hu/roundup/ffmpeg/issue27
http://adplug.sourceforge.net/library/
many OPL2/OPL3 audio formats not supported yet.


H.263 spec describing PB frames and improved PB frames: http://www.itu.int/rec/T-REC-H.263-200501-I/en
http://mikmod.raphnet.net/
http://mikmod.raphnet.net/#features
many music pattern formats not supported yet.


=== Patch cleanup for MPEG 1 & 2 optimizations ===
http://www.fly.net/~ant/libs/audio.html#Game_Music_Emu
Details are in the issue tracker: http://roundup.mplayerhq.hu/roundup/ffmpeg/issue100
AY
GBS
GYM
HES
KSS
NSF, NSFE
SAP
[[SNES-SPC700 Sound Format]]
VGM, VGZ


=== Implement a Vivo demuxer for FFmpeg ===
=== vloopback output support ===
Implement an FFmpeg demuxer for the [[Vivo]] file format. The best reference for understanding the format would be MPlayer's [http://svn.mplayerhq.hu/mplayer/trunk/libmpdemux/demux_viv.c?view=markup existing .viv demuxer].


This task corresponds to issue 99: http://roundup.mplayerhq.hu/roundup/ffmpeg/issue99
vloopback is a linux kernel device which allows to create a virtual video device where
programs can write, and can be accessed as a normal video device:
http://www.lavrsen.dk/twiki/bin/view/Motion/VideoFourLinuxLoopbackDevice


''I am ready to help out with understanding MPlayer's demuxer, esp. MPlayer API stuff if necessary.
This would allow to write the ffmpeg output to a vloopdevice and be displayed by some a
--[[User:Reimar|Reimar]] 15:46, 1 March 2008 (EST)
program reading from such device (e.g. skype, a voip client etc.).


=== Port missing demuxers from MPlayer to FFmpeg ===
An example of a program which uses vloopback:
MPlayer supports a few container formats in libmpdemux that are not yet present in libavformat. Porting them over and gettting them relicensed as LGPL or reimplementing them from scratch should make reasonable small tasks.
http://www.ws4gl.org/
 
 
=== Port video filters from MPlayer/VLC/Mjpegtools/Effectv/etc etc to libavfilter ===
 
There are plenty programs providing their own filters, many of them may be easily ported to the
superior ;-) framework of libavfilter. Also may be possible to create wrappers around other libraries
(e.g. opencv, libgimp, libshowphoto, libaa).
 
=== rar/zip/gz/bz2 etc demuxer ===
there are still compressed files out there (zipped raw wav, multi-rar'ed videos etc). create a decompression demuxer for them.


''Jai Menon is working on porting the tivo demuxer''
=== Less common AAC decoder features ===


=== Optimal Huffman tables for (M)JPEG ===
Add support to the AAC decoder for object type ER AAC LC or AAC LC 960.
This task is outlined at http://guru.multimedia.cx/small-tasks-for-ffmpeg/ and is tracked in the issue tracker: http://roundup.mplayerhq.hu/roundup/ffmpeg/issue267


=== YOP Playback System ===
=== arithmetic decoding (and encoding) for mjpeg ===
This task is to implement an FFmpeg playback subsystem for [[Psygnosis YOP]] files. This will entail writing a new file demuxer and video decoder, both of which are trivial by FFmpeg standards. [[Psygnosis YOP|The Psygnosis YOP page]] contains the specs necessary to complete this task and points to downloadable samples.
Following marker codes are not supported by our mjpeg decoder:
DAC, SOF9, SOF10, SOF11, SOF13, SOF14 and SOF15.
*any samples?


=== M95 Playback System ===
This task is to implement an FFmpeg playback subsystem for [[M95]] files. This will entail writing a new file demuxer and video decoder (the audio is already uncompressed), both of which are trivial by FFmpeg standards. [[M95|The M95 page]] contains the specs necessary to complete this task and points to downloadable samples.


=== BRP Playback System ===
This task is to implement an FFmpeg playback subsystem for [[BRP]] files. This will entail writing a new file demuxer as well as a video decoder that can handle at least 2 variations of format data. Further, write an audio decoder for the custom DPCM format in the file. All of these tasks are considered trivial by FFmpeg standards. [[BRP|The BRP page]] contains the specs necessary to complete this task and points to downloadable samples for both known variations.


=== 16-bit Interplay Video Decoder ===
=== adobe http f4f segmented fragmentation dynamic streaming format ===
FFmpeg already supports [[Interplay MVE]] files with [[Interplay Video|8-bit video data]] inside. This task involves supporting 16-bit video data. The video encoding format is mostly the same but the pixel size is twice as large. Engage the ffmpeg-devel list to discuss how best to approach this task.
sample streams on http://www.fox.com . command line instructions for creating such files: http://help.adobe.com/en_US/HTTPStreaming/1.0/Using/WS9463dbe8dbe45c4c-c126f3b1260533756d-7ffc.html . spec is available under adobe NDA. not to be confused with freely available F4V specification. open source php to convert f4f to flv: https://github.com/svnpenn/dotfiles/blob/master/etc/AdobeHDS.php


=== 16-bit VQA Video Decoder ===
=== get 3IV1 decoder working and benchmark ===
FFmpeg already supports Westwood [[VQA]] files. However, there are 3 variations of its custom video codec. The first 2 are supported in FFmpeg. This task involves implementing support for the 3rd variation. Visit the VQA samples repository: http://samples.mplayerhq.hu/game-formats/vqa/ -- The files in the directories Tiberian Sun VQAs/, bladerunner/, and dune2000/ use the 3rd variation of this codec. The [[VQA|VQA page]] should link to all the details you need to support this format.
we have a decoder for 3IV1. its currently if 0'd in the mpeg4 decoder. your task is to test if it still builds and works, and fix it so that it does not slow down mpeg4 decoder if enabled. the end goal is to enable it by default.


=== HNM4 Playback System ===
== Reverse Engineering Tasks ==
This task is to implement an FFmpeg playback subsystem for [[HNM4]] variant of the [[HNM]] format. This will entail writing a new file demuxer and video decoder, both of which are trivial by FFmpeg standards. [[HNM4|The HNM4 page]] contains the specs necessary to complete this task and links to downloadable samples.


=== FunCom ISS Playback System ===
=== Demuxer for csf format and video codec ===
This task is to implement an FFmpeg playback subsystem for [[FunCom ISS]] files. This will entail writing a new file demuxer and connecting it to the existing FFmpeg decoder for IMA ADPCM data. [[FunCom ISS|The FunCom ISS page]] contains the specs necessary to complete this task and links to downloadable samples.
This is partially analyzed in http://ffmpeg.org/trac/ffmpeg/ticket/1060


''See http://article.gmane.org/gmane.comp.video.ffmpeg.devel/66280 as a starting point -- Jai''
=== pick a random binary codec from mplayer ===
[[MPlayer]] has over 100 binary codecs which have no opensource decoder. pick one, find a sample and try to reverse engineer it. note that some work has been done on some codecs, and its a good idea to ask on the mailing list before starting.


=== Apple RPZA encoder ===
=== emblaze demuxer/decoder from java code ===
A patch was once sent to the ffmpeg-devel mailing list to include an encoder for the [[Apple RPZA]] video codec. That code can be found on the "[[Interesting Patches]]" page. This qualification task involves applying that patch so that it can compile with current FFmpeg SVN code and then cleaning it up per the standards of the project. Engage the mailing list to learn more about what to do.
samples and java decoder: http://samples.mplayerhq.hu/internets/emblaze/


=== QuickTime Edit List Support ===
=== audio sample suite ===
Implement edit list support in FFmpeg's QuickTime demuxer (libavformat/mov.c). This involves parsing the 'elst' atom in a QuickTime file. For a demonstration of how this is a problem, download the file menace00.mov from http://samples.mplayerhq.hu/mov/editlist/ and play it with ffplay or transcode it with ffmpeg. Notice that the audio and video are ever so slightly out of sync. Proper edit list support will solve that. Other samples in that directory also presumably exhibit edit list-related bugs. The [http://xine.cvs.sourceforge.net/xine/xine-lib/src/demuxers/demux_qt.c?view=markup Xine demuxer] has support for this, it might be useful for hints.
check and add support for these old audio formats: http://www-mmsp.ece.mcgill.ca/documents/AudioFormats/index.html


=== Reimplement libavcodec/fdctref.c ===
== Non-Programming Tasks ==
The forward double precision DCT in this file has a non-free license. We need an LGPL replacement of this file.


=== Implement the Flash Screen Video codec version 2 ===
=== Check Linux distributions for patches to ffmpeg ===
FFmpeg is missing both a decoder and an encoder. Would be nice to have that.


=== Add wma fixed point decoder back into libavcodec ===
check various distros like Fedora, Ubuntu, Debian, Mint, Arch, Suse etc for patches to ffmpeg. write down location of patches so it can be checked on an annual basis. if patches are found , report to ffmpeg-devel mailing list or bug trac.
http://svn.rockbox.org/viewvc.cgi/trunk/apps/codecs/libwma/
Rockbox's fixed-point WMA decoder was adapted from the decoder in libavcodec.


=== RealAudio 14.4 encoder ===
FFmpeg contains a decoder for [[RealAudio 14.4]], a farily simple integer CELP codec.  Write an encoder.  This would be a good qualification task for anyone interested in working on AMR, Speex, or sipr.


=== VC1 timestamps in m2ts ===
=== improve layout and accessability of ffmpeg website ===


Codec copy of VC1 from m2ts currently doesn't work. Either extend the VC1 parser to output/fix timestamps, or fix the timestamps from m2ts demuxing.
test ffmpeg.org with various browsers, including screen readers and get it optimized and available to people with poor vision. check wording and general ease of use. for example putting large download links for users like vlc and firefox have.


''was: Add support for newer codecs such as [[Dirac]] and [[VC1]] to FFmpeg's [[Matroska]] muxer.''
:''[[Dirac]] should mux perfectly as of r16261. What about muxing [[VC1]] doesn't work? A quick -vcodec copy from wmv didn't throw any errors. -[[User:Yuvi|Yuvi]] 05:31, 3 January 2009 (EST)''
::''Yes, WMV3 works fine.  There was a report that muxing VC1 from m2ts didn't work.  If this does work then feel free to remove the task.  Also the demuxer doesn't recognize V_VC1.  ''-[[User:Mkhodor|Mkhodor]] 22:58, 4 January 2009 (EST)
:::''From m2ts, ffmpeg gives "error, pts < dts" which means that the timestamps coming out of the m2ts demuxer are invalid. I dunno if it would be easier to fix the demuxer or just extend the parser to fix/fill them in. For V_VC1, is that actually used by a muxer now? According to http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-August/034825.html it was a brief mistake that isn't supposed to be used. -[[User:Yuvi|Yuvi]] 02:50, 5 January 2009 (EST)
::::''I don't know of any other muxers that use it, so I made a note on the [[Matroska]] page that it is deprecated.'' -[[User:Mkhodor|Mkhodor]] 10:47, 13 January 2009 (EST)


=== [[I263]] work ===
=== restore and update compatability page on ffmpeg website ===


This codec is supported only partially by FFmpeg. Add full support for it basing on the LGPL source code at http://multimedia.cx/I263Src.zip
we used to have a page that detailed how to create files for other software players and operating systems. restore this page from git history and update it for new devices and standardized codecs (h264 is the preferred codec now).


=== FLIC work ===


Revise the [[Flic Video]] decoder at libavcodec/flicvideo.c to support video transported in AVI or MOV files while making sure that data coming from the usual FLI files still works. 'AFLC' and 'flic' FourCC samples are linked from the [[Flic Video]] page.
=== contact large ffmpeg users for broken / unplayable samples ===
contact the largest users of ffmpeg, like youtube, facebook, archive.org, blip.tv and others and ask them for access to samples that do not decode correctly.


=== Auravision video decoder ===
=== review sample request error messages ===
ffmpeg has an av_log_ask_for_sample generic log message to ask the user for a sample when there is a problem. your task is to review ffmpeg decoders and demuxers (and possibly other inputs) and replace regular av_log messages requesting samples with it. example commit here: http://ffmpeg.org/pipermail/ffmpeg-cvslog/2011-April/036509.html


Implement a decoder based on the speculation put forth on the wiki page for [[Auravision]] video. Samples are linked from the Wiki page. This project might demonstrate that the speculation on the Wiki page is incorrect. That is also useful information.


=== Hook up QT YUV2 FourCC ===
=== write bluray and 3d howtos ===
write a document or wiki article or just link to some info on how to play + encode + rip bluray using ffmpeg/mplayer and the various bluray libs required. also a guide on how to use ffmpeg/mplayer/vlc to encode and play various 3D formats. including maybe some supported hardware screens/video cards w/ examples. includes updating this wiki page [[Blu Ray and HD-DVD Playback Status]]
[[How to make a 3d movie with ffmpeg]]


Wire up the YUV2 FourCC that can occur in [[MOV]] to the [[YUV 4:2:2]] colorspace. Samples are linked from the [[YUV 4:2:2]] wiki page.
[[Category:FFmpeg]]


=== CorePNG Decoder ===


Extend FFmpeg's PNG decoder to handle the difference frames and [[YUV]] colorspace added in [[CorePNG]]. Sample at [http://samples.mplayerhq.hu/V-codecs/PNG1/ http://samples.mplayerhq.hu/V-codecs/PNG1/]


=== CJPG format ===
=== write ipad/iphone/ios howto ===
write up some documentation on how to compile ffmpeg/ffplay/ffserver for iOS. exact tool versions, command lines, library requirements. both native compilation on the device and cross-compile using OS X. an android howto for various devices would be useful too.


Extend FFmpeg's MJPEG decoder to handle the different frames/packing of CJPG. Samples at: http://roundup.ffmpeg.org/roundup/ffmpeg/issue777
=== talk to downstream ===
talk to the big projects that use ffmpeg. see if there is anything ffmpeg can do to make things easier, be it api stabilization, backwards compatability, or turning private functions into public headers.


=== Optimize Theora Decoder ===
examples include videolan, perian, mplayer, xbmc, ffdshow-tryouts, gstreamer.


speed up the Theora decoder. [http://www.archive.org/download/AlternativeFreedom/alternative_freedom.ogg 720:480 sample] hits 100% cpu on a p4 1.5ghz.
==== migrate bugs from other projects ====
:''Do you have any specific optimizations tips? I like these small tasks to present a clearer jumping-off point. --[[User:Multimedia Mike|Multimedia Mike]] 18:57, 22 December 2008 (EST)''
many projects that use ffmpeg or libavcodec have bugs that are meant for ffmpeg. some of these projects dont have time to send them to us, so they rot on bugzillas.
::''did theora make use of the mmx/sse functions of ffvp3? i was looking at the xiph GSOC page which mentioned a similar task. --[[User:Compn|Compn]] 21:17, 22 December 2008 (EST)''
::''The major optimization I can think of is reworking coefficient decoding to avoid the continue in unpack_vlcs() (basically by having a list of coefficient VLCs for each position rather than for each block, then decoding them when actually rendering the block.) Unfortunately this also requires reworking render_slice() and reverse_dc_prediction() quite significantly which is why I haven't done it yet. [[User:Yuvi|Yuvi]] 18:25, 23 December 2008 (EST)''


==== review any local patches ====
some projects may patch ffmpeg. collect these patches and compare them with other projects. see if there is anything we can do to reduce external patches.


=== flip flag for upside-down codecs ===


<pre>about the flip, a patch that decodes images fliped when
[[Category:FFmpeg]]
codec_tag == ff_get_fourcc("GEOX") is welcome.
its a metter of 2lines manipulating data/linesize of imgages after
get_buffer() or something similar
[...]
--
Michael    GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
</pre>
more info:
https://roundup.mplayerhq.hu/roundup/ffmpeg/issue741

Latest revision as of 09:00, 22 February 2017

This page contains ideas for small, relatively simple tasks for the FFmpeg project. People who might be interested in trying one of these tasks:

  • Someone who wants to contribute to FFmpeg and needs to find a well-defined task to start with
  • Someone who wishes to qualify for one of FFmpeg's coveted Summer of Code project slots
  • An existing FFmpeg developer who has been away from the project for a while and needs a smaller task as motivation for re-learning the codebase

For other tasks of varying difficulty, see the Interesting Patches page.

If you would like to work on one of these tasks, please take these steps:

If you would like to add to this list, please be prepared to explain some useful details about the task. Excessively vague tasks with no supporting details will be ruthlessly deleted.

The FFmpeg project always needs people to do the following tasks:

  1. Review bugs on the FFmpeg bug tracker
    1. verifying bugreports are complete with 'ffmpeg -i' output
    2. making sure samples are mirrored/available
    3. verifying bugs against current git master
  2. Review patches posted to ffmpeg-devel mailing list
    1. also test to make sure they compile against git master and dont break 'make fate' / compilation
  3. Review documentation and update examples in documentation.
    1. updating and adding more information to the howto and api documents
    2. make a guide how to embed ffmpeg into various programming languages, be it c++, java, mono, c#, etc

Programming Tasks

Finish up a previous incomplete SoC project

Several SoC projects from previous years have not yet made it into FFmpeg. Taking any of them and finishing them up to the point that they can be included should make for a good qualification task. Check out the FFmpeg Summer Of Code overview page and look for the unfinished projects, like the TS muxer.

Add code to validate get_buffer usage of decoders

Change the default_get_buffer etc. functions to enforce the minimum guarantees the decoder requests. E.g. if a decoder does not set FF_BUFFER_HINTS_READABLE, return a buffer without read permissions (using e.g. mprotect). If the decoder does not use reget_buffer, always return a buffer initialized with random data. If the decoder does not set FF_BUFFER_HINTS_PRESERVE, always destroy the buffer contents as soon as possible. Make reget_buffer always fail if FF_BUFFER_HINTS_REUSABLE was not used. Probably more things that could be done.

Port missing demuxers from MPlayer

MPlayer supports a few container formats in libmpdemux that are not yet present in libavformat. Porting them over and gettting them relicensed as LGPL or reimplementing them from scratch should make reasonable small tasks.

  1. TiVo --
  2. SL support for MPEG-TS (anyone got samples?)
  3. MNG -- Paul B Mahol is working on this

M95 Playback System

This task is to implement a playback subsystem for M95 files. This will entail writing a new file demuxer and video decoder (the audio is already uncompressed), both of which should be fairly easy by FFmpeg standards. The M95 page contains the specs necessary to complete this task and points to downloadable samples.

BRP Playback System

This task is to implement a playback subsystem for BRP files. This will entail writing a new file demuxer as well as a video decoder that can handle at least 2 variations of format data. Further, write an audio decoder for the custom DPCM format in the file. All of these tasks are considered fairly easy by FFmpeg standards. The BRP page contains the specs necessary to complete this task and points to downloadable samples for both known variations.

16-bit VQA Video Decoder

Westwood VQA files are already supported. However, there are three variations of its custom video codec, only the first two of which are supported. This task involves implementing support for the third variation. Visit the VQA samples repository: http://samples.multimedia.cx/game-formats/vqa/ -- The files in the directories Tiberian Sun VQAs/, bladerunner/, and dune2000/ use the 3rd variation of this codec. The VQA page should link to all the details you need to support this format.

Discussion/patch: http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/89902/focus=90433 http://thread.gmane.org/gmane.comp.video.ffmpeg.devel/173307/focus=173308

Apple RPZA encoder

A patch was once sent to the ffmpeg-devel mailing list to include an encoder for the Apple RPZA video codec. That code can be found on the "Interesting Patches" page. This qualification task involves applying that patch so that it can compile with current HEAD and then cleaning it up per the standards of the project. Engage the mailing list to learn more about what to do.

QuickTime Edit List Support

Implement edit list support in the QuickTime demuxer (libavformat/mov.c). This involves parsing the 'elst' atom in a QuickTime file. For a demonstration of how this is a problem, download the file menace00.mov from http://samples.mplayerhq.hu/mov/editlist/ and play it with ffplay or transcode it with ffmpeg. Notice that the audio and video are ever so slightly out of sync. Proper edit list support will solve that. Other samples in that directory also presumably exhibit edit list-related bugs. The Xine demuxer has support for this, it might be useful for hints.

(patch was submitted to ffmpeg-devel , around 14 March 2009)

merge all fixed point decoders back into libavcodec

http://git.rockbox.org/?p=rockbox.git;a=tree;f=lib/rbcodec/codecs Rockbox's fixed-point decoders are based on decoders from libavcodec.

flip flag for upside-down codecs

about the flip, a patch that decodes images fliped when
codec_tag == ff_get_fourcc("GEOX") is welcome.
its a metter of 2lines manipulating data/linesize of imgages after
get_buffer() or something similar
[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

more info: http://ffmpeg.org/trac/ffmpeg/ticket/317

support for YCoCg/RGB colorspace in FFV1

Add support for YCoCg and RGB encoded sources for the FFV1 codec

This would add a free lossless intra-frame RGB codec for all supported platforms (most important OS X + Windows) which is often asked for video editing in video forums (e.g. slashcam.de)

IFF ANIM decoder

Modify libavformat/iff.c to handle this chunk and write a decoder for the format. The wiki page at IFF ANIM has links to more information and source code. Samples can be found at http://www-user.tu-chemnitz.de/~womar/projects/iffanim/iffanim_samplepack.zip .


port missing decoders/demuxers from other open source projects.

http://www.mega-nerd.com/libsndfile/#Features 

GNU Octave 2.0 MAT4
GNU Octave 2.1 MAT5
Designer II SD2

samples are here: http://www.mega-nerd.com/tmp/SoundFileCollection-20050711-0902.tgz

http://www.hawksoft.com/hawkvoice/ 

HVDI_VOICE_DATA- packet
GSM
LPC
CELP
LPC10

http://sourceforge.net/projects/vgmstream 

150+ formats: http://vgmstream.svn.sourceforge.net/viewvc/vgmstream/readme.txt

http://www.imagemagick.org http://www.graphicsmagick.org/formats.html 

many image formats not supported yet.

http://gpac.sourceforge.net/ 

MPEG-4 BIFS
3GPP DIMS
LASeR
SAF
SVG
SMIL
VRML
X3D
XMT

http://adplug.sourceforge.net/ http://adplug.sourceforge.net/library/ 

many OPL2/OPL3 audio formats not supported yet.

http://mikmod.raphnet.net/ http://mikmod.raphnet.net/#features 

many music pattern formats not supported yet.

http://www.fly.net/~ant/libs/audio.html#Game_Music_Emu 

AY
GBS
GYM
HES
KSS
NSF, NSFE
SAP
SNES-SPC700 Sound Format
VGM, VGZ

vloopback output support

vloopback is a linux kernel device which allows to create a virtual video device where programs can write, and can be accessed as a normal video device: http://www.lavrsen.dk/twiki/bin/view/Motion/VideoFourLinuxLoopbackDevice

This would allow to write the ffmpeg output to a vloopdevice and be displayed by some a program reading from such device (e.g. skype, a voip client etc.).

An example of a program which uses vloopback: http://www.ws4gl.org/


Port video filters from MPlayer/VLC/Mjpegtools/Effectv/etc etc to libavfilter

There are plenty programs providing their own filters, many of them may be easily ported to the superior ;-) framework of libavfilter. Also may be possible to create wrappers around other libraries (e.g. opencv, libgimp, libshowphoto, libaa).

rar/zip/gz/bz2 etc demuxer

there are still compressed files out there (zipped raw wav, multi-rar'ed videos etc). create a decompression demuxer for them.

Less common AAC decoder features

Add support to the AAC decoder for object type ER AAC LC or AAC LC 960.

arithmetic decoding (and encoding) for mjpeg

Following marker codes are not supported by our mjpeg decoder: DAC, SOF9, SOF10, SOF11, SOF13, SOF14 and SOF15.

  • any samples?


adobe http f4f segmented fragmentation dynamic streaming format

sample streams on http://www.fox.com . command line instructions for creating such files: http://help.adobe.com/en_US/HTTPStreaming/1.0/Using/WS9463dbe8dbe45c4c-c126f3b1260533756d-7ffc.html . spec is available under adobe NDA. not to be confused with freely available F4V specification. open source php to convert f4f to flv: https://github.com/svnpenn/dotfiles/blob/master/etc/AdobeHDS.php

get 3IV1 decoder working and benchmark

we have a decoder for 3IV1. its currently if 0'd in the mpeg4 decoder. your task is to test if it still builds and works, and fix it so that it does not slow down mpeg4 decoder if enabled. the end goal is to enable it by default.

Reverse Engineering Tasks

Demuxer for csf format and video codec

This is partially analyzed in http://ffmpeg.org/trac/ffmpeg/ticket/1060

pick a random binary codec from mplayer

MPlayer has over 100 binary codecs which have no opensource decoder. pick one, find a sample and try to reverse engineer it. note that some work has been done on some codecs, and its a good idea to ask on the mailing list before starting.

emblaze demuxer/decoder from java code

samples and java decoder: http://samples.mplayerhq.hu/internets/emblaze/

audio sample suite

check and add support for these old audio formats: http://www-mmsp.ece.mcgill.ca/documents/AudioFormats/index.html

Non-Programming Tasks

Check Linux distributions for patches to ffmpeg

check various distros like Fedora, Ubuntu, Debian, Mint, Arch, Suse etc for patches to ffmpeg. write down location of patches so it can be checked on an annual basis. if patches are found , report to ffmpeg-devel mailing list or bug trac.


improve layout and accessability of ffmpeg website

test ffmpeg.org with various browsers, including screen readers and get it optimized and available to people with poor vision. check wording and general ease of use. for example putting large download links for users like vlc and firefox have.


restore and update compatability page on ffmpeg website

we used to have a page that detailed how to create files for other software players and operating systems. restore this page from git history and update it for new devices and standardized codecs (h264 is the preferred codec now).


contact large ffmpeg users for broken / unplayable samples

contact the largest users of ffmpeg, like youtube, facebook, archive.org, blip.tv and others and ask them for access to samples that do not decode correctly.

review sample request error messages

ffmpeg has an av_log_ask_for_sample generic log message to ask the user for a sample when there is a problem. your task is to review ffmpeg decoders and demuxers (and possibly other inputs) and replace regular av_log messages requesting samples with it. example commit here: http://ffmpeg.org/pipermail/ffmpeg-cvslog/2011-April/036509.html


write bluray and 3d howtos

write a document or wiki article or just link to some info on how to play + encode + rip bluray using ffmpeg/mplayer and the various bluray libs required. also a guide on how to use ffmpeg/mplayer/vlc to encode and play various 3D formats. including maybe some supported hardware screens/video cards w/ examples. includes updating this wiki page Blu Ray and HD-DVD Playback Status How to make a 3d movie with ffmpeg



write ipad/iphone/ios howto

write up some documentation on how to compile ffmpeg/ffplay/ffserver for iOS. exact tool versions, command lines, library requirements. both native compilation on the device and cross-compile using OS X. an android howto for various devices would be useful too.

talk to downstream

talk to the big projects that use ffmpeg. see if there is anything ffmpeg can do to make things easier, be it api stabilization, backwards compatability, or turning private functions into public headers.

examples include videolan, perian, mplayer, xbmc, ffdshow-tryouts, gstreamer.

migrate bugs from other projects

many projects that use ffmpeg or libavcodec have bugs that are meant for ffmpeg. some of these projects dont have time to send them to us, so they rot on bugzillas.

review any local patches

some projects may patch ffmpeg. collect these patches and compare them with other projects. see if there is anything we can do to reduce external patches.

Retrieved from "https://wiki.multimedia.cx/index.php?title=Small_FFmpeg_Tasks&oldid=15270"