Libavfilter

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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.

Possible known issues

  • no frame rate estimation is supported (see post in -soc [1])
  • make ffmpeg.c honor the aspect ratio outputted by the filter chain (thanks vdmsss for the bug report) -- Updated: probably fixed, but maybe not printing the right PAR in the terminal

Feature wish list

Warning: This is not an official wish list. Before implementing any one of these items, ask first in the ffmpeg-devel mailing-list.

See also