Small FFmpeg Tasks

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:

• Subscribe to the FFmpeg development mailing list and indicate your interest
• Ask 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.

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.

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. --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)

Make the SoC dts encoder multichannel capable

Here is a skeleton for a dts encoder http://svn.mplayerhq.hu/soc/dcaenc/, 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: http://wiki.multimedia.cx/index.php?title=DTS

GIF LZW Encoder and extend Encoder and Decoder to support Animated GIFs

Lzw encoder is already used for TIFF, it must be extended to support GIF flavor.

Patch cleanup for MPEG 1 & 2 optimizations

Details are in the issue tracker: http://roundup.ffmpeg.org/roundup/ffmpeg/issue100

Implement a Vivo demuxer for FFmpeg

Implement an FFmpeg 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: http://roundup.ffmpeg.org/roundup/ffmpeg/issue99

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 to FFmpeg

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.

Jai Menon is working on porting the tivo demuxer

Optimal Huffman tables for (M)JPEG

This task is outlined at http://guru.multimedia.cx/small-tasks-for-ffmpeg/ and is tracked in the issue tracker: http://roundup.ffmpeg.org/roundup/ffmpeg/issue267

YOP Playback System

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. The Psygnosis YOP page contains the specs necessary to complete this task and points to downloadable 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. 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. 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

FFmpeg already supports Interplay MVE files with 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.

16-bit VQA Video Decoder

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 page should link to all the details you need to support this format.

HNM4 Playback System

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. 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 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.

QuickTime Edit List Support

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 Xine demuxer has support for this, it might be useful for hints.

Reimplement libavcodec/fdctref.c

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

FFmpeg is missing both a decoder and an encoder. Would be nice to have that.

Add wma fixed point decoder back into libavcodec

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

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.

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. -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. -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. -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. -Mkhodor 10:47, 13 January 2009 (EST)

I263 work

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

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.

Auravision video decoder

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

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.

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/

Extend PNG Decoder

get this png working in ffpng: http://roundup.ffmpeg.org/roundup/ffmpeg/issue813 .

CJPG format

Extend FFmpeg's MJPEG decoder to handle the different frames/packing of CJPG. Samples at: http://roundup.ffmpeg.org/roundup/ffmpeg/issue777

Optimize Theora Decoder

speed up the Theora decoder. 720:480 sample hits 100% cpu on a p4 1.5ghz.

Do you have any specific optimizations tips? I like these small tasks to present a clearer jumping-off point. --Multimedia Mike 18:57, 22 December 2008 (EST)

did theora make use of the mmx/sse functions of ffvp3? i was looking at the xiph GSOC page which mentioned a similar task. --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. Yuvi 18:25, 23 December 2008 (EST)

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://roundup.ffmpeg.org/roundup/ffmpeg/issue741

lavf-based concatenation tool

Unless we have multiple files input in FFmpeg, 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: http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2009-February/063647.html 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.

Add waveformat extensible support in wav muxer

http://article.gmane.org/gmane.comp.video.ffmpeg.devel/79503 Clean up that patch.

implement some colorspace fourcc/codecs

some colorspace formats were uploaded to http://samples.mplayerhq.hu/V-codecs/ including:

2vuy.avi
CYUV.AVI
P422.AVI
UYNV.AVI
UYNY.avi
V422.AVI
YUNV.AVI
a12v.avi
auv2.avi
and V-codecs/yuv8/MAILTEST.AVI .