Libavfilter
Until it is incorporated into FFmpeg, you may get the libavfilter source from GSoC SVN repository:
svn checkout svn://svn.mplayerhq.hu/soc/libavfilter
Please read its README to discover how to integrate it with ffmpeg and ffplay.
Reasons why a filter API is needed in FFmpeg
FFmpeg's already well-known libavcodec module has become the de facto standard library for video decoding and encoding in free software projects. Unfortunately, no similar standard library has surfaced for audio/video filtering and otherwise working with audio/video stream once it has been decoded. Various multimedia projects (such as MPlayer, Xine, GStreamer, VirtualDub, etc.) have implemented their own filter systems to various degrees of success. What is needed is a high quality audio and video filter API - efficient, flexible enough to meet all the requirements which have led various projects to invent their own filter system, and yet easy to use or develop new filters with. This proposal is to implement a high quality video API and filter library for FFmpeg, where it can be easily used by other multimedia-related software projects.
Issues that have to be fixed before adding to main tree
- ffmpeg.c/ffplay.c integration is broken (more details in -soc post [1])
- no frame rate estimation is supported (see post in -soc [2])
Feature wish list
Warning: This is not an official wish list. Before implementing any one of these items, ask first in ffmpeg-devel.
- See the TODO file in SoC SVN tree
- Create a SDK (Software Development Kit) with templates for the A/V filter APIs
- Add support for audio filters
- See FFmpeg audio API
- Add support for subtitle filters
- Add a subtitle drawing support to simplify ffplay.c
- Create (or port) additional pre-process and post-process video filters to FFmpeg:
- General post-proc sources are MPlayer (libmpcodecs vf_*.c filters), Xine, FFdshow, VLC, VirtualDub, GStreamer, foobar, and XMMS, vhook
- More image scaling methods:
- SSP (Statistical Post-Processing)
- DeBlocking
- DeRinging
- IVTC
- Sharpen / UnSharpen (Soften)
- ReQuantization
- Auto-Luminance
- Blurring / DeNoising / Spatial Blur / Temporal Blur
- Deinterlace (weave AND bob) filters
- 2:3 pull-down / ivtc (inverse telecine) for 24 progressive-frames on 30 FPS TV's
- NTSC => PAL, and PAL => NTSC frame-rate (FPS) adjust and reclock filter for NTSC <=> PAL conversion
Past discussions on the topic
Threads with previous discussions in the subject:
- Possible adopt MPlayer's A/V filter system or create a new API 'from scratch' for pre-process and post-process audio/video filters:
- See http://article.gmane.org/gmane.comp.video.ffmpeg.devel/39130 for michaelni's idea of what to do.
- Also read this discussion thread on MPlayer's mailing-list:
- See http://article.gmane.org/gmane.comp.video.ffmpeg.devel/39130 for michaelni's idea of what to do.
- Take a look at other existing players API for filter plugins, like for example;
Mentors
A'rpi (has expressed interest of possibly helping with implementing a filter API in FFmpeg, he also volunteering to help porting the MPlayer filters too if a such API becomes available http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2007-April/051164.html)