GStreamer is a streaming media framework, based on graphs of filters which
operate on media data. Applications using this library can do anything
from real-time sound processing to playing videos, and just about anything
else media-related. Its plugin-based architecture means that new data
types or processing capabilities can be added simply by installing new
plugins.

GStreamer Good Plugins is a collection of well-supported plugins of
good quality and under the LGPL license.