binutils - Recommended version is 2.11.x. This program is responsible for generating MMX/ 3DNow!/etc instructions, thus very important.

gcc - Recommended versions are 2.95 and 3.3+. 2.96 and 3.0.x are known to generate faulty code, 3.1 and 3.2 also had problems. On PowerPC, use 4.x+.

XFree86 - Recommended version is always the newest (4.3). Normally, everyone wants this, as starting with XFree86 4.0.2, it contains the XVideo extension (somewhere referred to as Xv) which is needed to enable the hardware YUV acceleration (fast image display) on cards that support it. Make sure its development package is installed, too, otherwise it won't work. For some video cards you don't need XFree86. See list below.

make - Recommended version is always the newest (at least 3.79.x). This usually isn't important.

FreeType 2.0.9 or later is required to have a font for the OSD and subtitles.

SDL - it's not mandatory, but can help in some cases (bad audio, video cards that lag strangely with the xv driver). Always use the newest (beginning from 1.2.x).

libjpeg - optional JPEG decoder, used by the -mf option and some QT MOV files. Useful for both MPlayer and MEncoder if you plan to work with jpeg files.

libpng - recommended and default (M)PNG decoder. Required for GUI. Useful for both MPlayer and MEncoder.

lame - recommended, needed for encoding MP3 audio with MEncoder, recommended version is always the newest (at least 3.90).

zlib - recommended, necessary for compressed MOV header and PNG support.

libogg - optional, needed for playing OGG file format.

libvorbis - optional, needed for playing OGG Vorbis audio.

LIVE555 Streaming Media - optional, needed for playing RTSP/RTP streams.

directfb - optional, from http://www.directfb.org. At least 0.9.13 is required.

cdparanoia - optional, for CDDA support

libxmms - optional, for XMMS input plugin support. At least 1.2.7 is required.

libsmb - optional, for Samba support.

ALSA - optional, for ALSA audio output support. At least 0.9.0rc4 is required.

bio2jack - optional, for JACK audio output support, needed only in compile time. You can obtain it from http://bio2jack.sf.net. Since it doesn't have install option you have to manually put the file libbio2jack.a somewhere in your library path (e.g. /usr/local/lib) or use the --with-bio2jack=DIR switch to tell ./configure where that file is.