Small FFmpeg Tasks

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

  • Someone who wants to contribute to Libav and needs to find a well-defined task to start with
  • Someone who wishes to qualify for one of Libav's coveted Summer of Code project slots
  • An existing Libav 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.

Finish up a previous incomplete SoC project

Several SoC projects from previous years have not yet made it into Libav. 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 Libav Summer Of Code overview page and look for the unfinished projects.

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 Libav'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. --Multimedia Mike 12:56, 25 February 2008 (EST)

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 ? --Baptiste Coudurier 00:30, 29 February 2008 (EST)

* Adding the YCoCg colorspace (with different sized planes) for RGB sourced pictures would be nice too. Elte 07:15, 16 March 2009 (EDT)

Make the SoC dts encoder multichannel capable

Here is a skeleton for a dts encoder, currently it can only encode stereo streams. The task is to extend it to support 5.1 channels also.

Specs and info can be found here:

Extend GIF Encoder and Decoder to support Animated GIFs

reverse engineer realplayer's ivr format and create a demuxer for it

samples on IVR page.

Implement a Vivo demuxer

Implement a demuxer for the Vivo file format. The best reference for understanding the format would be MPlayer's existing .viv demuxer.

This task corresponds to issue 99:

I am ready to help out with understanding MPlayer's demuxer, esp. MPlayer API stuff if necessary. --Reimar 15:46, 1 March 2008 (EST)

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 -- Jai Menon is working on this
  2. VIVO -- Daniel Verkamp has a patch for this
  3. SL support for MPEG-TS (anyone got samples?)
  4. MNG

Optimal Huffman tables for (M)JPEG

This task is outlined at and is tracked in the issue tracker:

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. 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. 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: -- 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: (reference)

HNM4 Playback System

This task is to implement a playback subsystem for HNM4 variant of the HNM format. This will entail writing a new file demuxer and video decoder, both of which are considered fairly easy. The HNM4 page contains the specs necessary to complete this task and links to downloadable samples.

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 from 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)

Implement the Flash Screen Video codec version 2

Both a decoder and an encoder are missing, but would be nice to have.

Daniel Verkamp is working on this

Add wma fixed point decoder back into libavcodec Rockbox's fixed-point WMA decoder was adapted from the decoder in libavcodec.

VC1 timestamps in m2ts

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.

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.

CJPG format

Extend the MJPEG decoder to handle the different frames/packing of CJPG. Samples at:

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:

lavf-based concatenation tool

It would be nice to have some libavformat-based tool that would extract frames from multiple files (possible different containers as well) and put them into single one.

cljr and vcr1 encoders

According to this: both of the encoders are disabled, and won't compile if enabled. Michael would prefer to keep them around, and have someone grow them into full encoders.

implement some colorspace fourcc/codecs

some colorspace formats were uploaded to including:

CYUV.AVI is 8 Bit Interleaved 4:2:2
a12v.avi is 4:2:2:4 10 Bit Interleaved
auv2.avi is 4:2:2:4 8 Bit Interleaved
and V-codecs/yuv8/MAILTEST.AVI .

it might decode with current pixfmts, a sample commit is 9853bbb21a19d540850de60d3e9cf7c6ef9da7dc

a sample commit for adding new input formats to swscale is 4884b9e50d416f84e64bfaf546a03e490cb83a2f

the hunks 3 and 5 you do not need, they are optional special converters
also the change to isSupportedOut() you do not need
above will add a new input format

another example for adding an input format is a43fb6b37efa5b01f2c9bdc414570691229bcfab

Implement Phantom Cine demuxer and Bayer format support for swscale

The format is described here: It will need support for Bayer -> RGB conversion in swscale to make the demuxer useful though.

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.

Metal Gear Solid Video format demuxer

Write a demuxer to play video files harvested from the game Metal Gear Solid: The Twin Snakes. The format is described on the wiki page Metal Gear Solid VP3 (which also contains links to samples). This page is based on observations and conjecture, so remember to engage the mailing list or IRC with questions.

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 .

CDXL decoder

Write a decoder for this format using the information in the CDXL wiki page Discussed for the 2009 SoC

port missing decoders/demuxers from other open source projects.

Paris Audio File PAF
GNU Octave 2.0 MAT4
GNU Octave 2.1 MAT5
Portable Voice Format PVFSound
Designer II SD2

samples are here:


150+ formats:

many image formats not supported yet.


many OPL2/OPL3 audio formats not supported yet.

many music pattern formats not supported yet.

SNES-SPC700 Sound Format

port Ut Video decoder/encoder

gpl v2 decoder/encoder at wiki page

Sony psp demuxer

create/port a demuxer for the sony playstation portable format PMP.

libswscale PAL8 output

See the thread: "[RFC] libswscale palette output implementation":

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:

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:

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).

Add weighted motion compensation for B-frames in RV3/4

RealVideo 3 and 4 uses weighted motion compensation for B-frames (like H.264) but current code always uses simple averaging. Reverse-engineer weighted MC functions for B-frames and make RV3/4 decoder use them.

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.

rewrite rm demuxer

the rm demuxer was written before specs were available and has guesses, hacks and generally needs a cleanup/update.