Third party libraries used by VLC

You'll find a complete list on the wiki.

But, here are the most important libraries.

Audio/Video codecs
liba52 - an ATSC A/52 (aka AC3) audio decoder
libmad - an MPEG audio decoder
libmpeg2 - an MPEG1/2 video decoder
libavcodec (ffmpeg) - an extensive audio/video codec library which supports several formats like MPEG4, H263, WMV/A etc...
libogg - an Ogg bitstream parser
libvorbis - a Vorbis audio decoder
libflac - a FLAC (Free Lossless Audio Codec) audio decoder
libspeex - a Speex (Free speech codec) audio decoder
libtheora - a Theora video decoder
libfaad2 - an AAC audio decoder
libdv - a DV video decoder (deprecated in favor of libavcodec)
libxvidcore (xvid) - an ISO MPEG-4 compliant video codec (deprecated in favor of libavcodec)
libdca - A DTS Coherent Acoustics decoding library.

GUI framework libraries
wxWidgets - a cross-platform C++ GUI framework that keeps the look and feel of each platform
QT4 - a C++ Cross-Platform Rich Client Development Framework

Audio/Video output libraries
libsdl - a cross-platform multimedia library designed to provide level access to audio, and 2D video framebuffer

Miscellaneous libraries
libdvdcss - a library for accessing encrypted DVDs
libdvdnav - a library for DVD navigation
libdvdread - a library for reading DVD-Video images
libdvbpsi - a library designed for decoding and generation of MPEG TS and DVB PSI tables
libopenslp - an open-source implementation of Service Location Protocol
gettext - a set of tools that provides a framework to help applications produce multi-lingual messages
libfreetype2 - a software font engine that is designed to be small, efficient, highly customizable and portable while capable of producing high-quality output (glyph images).
fribidi - A Free Implementation of the Unicode Bidirectional Algorithm
liveMedia - C++ libraries for multimedia streaming (RTP/RTCP, RTSP, SIP)
matroska - a new, extensible open standard Audio/Video container format

If you're using those libs to compile VLC for windows with mingw-gcc 3.3.1, you can use our Win32 contribs.