Overview of Linux Multimedia

amp, with its last release in 1997, was created by Tomislav Uzelac while he was a graduate student at the University of Zagreb in Croatia. This is yet a very viable solution for playing MP3 audio files — it is non-interactive, and Just Works from the commandline. A webpage from the PlayMedia site refers to amp's MP3 decoding algorithms as "the Rolls-Royce of MP3 playback technology." What I like about it is that it's very simple, and works nicely in small scripts. amp comes with Slackware, and there is a Debian package for it in the "non-free" section; it's not GPL'd, but the source is available and the author describes it as "free software". AMP stands for "Advanced Multimedia Products", which was Uzelac's company, later absorbed by PlayMedia. AMP is also the AMP in X11AMP, WinAMP, and MacAMP, which are (or at one point were) derivative works.

To learn more about Tomislav Uzelac, see http://www.playmedia.hr/tomislav.htm.

mpg123 plays and decodes MP3 audio files, and does it rather well. It's generally used for its simplicity, and because it works nicely as a backend for other programs, some of which work from the commandline, under X, with ncurses, or from within Emacs. While its source is available, mpg123's license does not allow for commercial uses, and as such, it isn't Free Software. Take a look at mpg321 for a Free option.

mpg123 can be found at http://www.mpg123.de/.

mpg321 is a Free replacement for mpg123, intended to replicate its functionality and allow people to integrate its code into new projects without licensing entanglements. It uses the Ogg Vorbis project's libao, although as of yet it doesn't play Ogg files (for that, see ogg123). In a move that could either be seen as helpful or obnoxious, mpg321's install scripts by default create a symlink called mpg123 to the mpg321 binary.

mpg321 lives at http://mpg321.sourceforge.net/.

xmms stands for X MultiMedia System (formerly known as x11amp), and is a graphical, modular program, using various plugins to handle various sorts of media files that you might wish to play. It looks and feels very much like Winamp, for those familiar with that particular program. Most significantly, it's used to play MP3, although it also supports Ogg. xmms's plugin system allows new file formats, output methods, and effects to be added without disturbing the rest of the program. Particularly entertaining is the "voice removal" plugin, which comes with xmms. In a recent test, it managed to nearly completely remove Frank Sinatra's voice from "The Coffee Song", allowing for an almost perfect karaoke experience. Success with this particular plugin varies from vocalist to vocalist.

XMMS Screenshot

Ogg Vorbis is an "open, free" audio codec, free from patents and royalty problems, with a slick variable quality feature. It probably deserves its own presentation sometime later. Generally available are the excellent programs oggenc and ogg123, which encode and decode .ogg files, respectively. Particularly under Slackware, these ship as the "oggtools" package, but from vorbis.com, they can be had as vorbis-tools-1.0.tar.gz. These are not the only programs available for playing oggs, however — as mentioned earlier, xmms works nicely, as does Zinf (formerly FreeAMP), apparently. Various other packages are available, as are shell scripts to convert your entire MP3 collection into oggs. This is generally not considered as a good idea, however, as converting from one lossy format to another format lossy in different ways results in a cumulative loss of sound quality. The xiph.org folks recommend keeping one's MP3s (or just re-encoding straight from the CDs to Ogg) and encoding new music with oggenc, as many players can handle both formats. xmms supports Ogg Vorbis with no modification, and oggenc and ogg123 are very easy to use.

With great alacrity (and For Great Justice), take a look at:

http://www.xiph.org/

http://www.vorbis.com/

At one point, xanim was the standard in Linux video playback. It apparently works not only under a wide variety of Unices, but also on a VAX. The last version (at least for a while) 2.80.1, came out 21 March 1999. These days, there may be some better options for video playback, but xanim is interesting for historical purposes. Apparently xanim can handle AVI, Quicktime (!), SGI Movie Format, and various other (more obscure) video codecs. It also can read audio and image files of various descriptions.

xanim home: http://xanim.ba.pubnix.com/

MPlayer can play your video for you. It does divx and most of the formats that you might expect to run across. It can also play DVDs, when compiled with libdvdread and libdvdcss installed. Thankfully, libdvdread and libdvdcss are relatively easy to find, download, and install. Earlier versions of mplayer could use Microsoft objects to decode DivX files (w32codecs.tgz), but these days, mplayer comes with FFMpeg, an open source alternative. mplayer can be used a few different ways to write to your X display, specified by the -vo option. On cards with Xv support, using -vo xv is a good idea. mplayer -vo help lists the possibilities for video output.

MPlayer is generally called from the command line. Here are a few examples of how it might be used.

mplayer -vo xv -framedrop -fs -zoom -dvd 1 -dvd-device /dev/cdrom}

mplayer -vo xv sailormoon.avi

mplayer -vo xv -fs -zoom sailormoon.avi

Check out: http://www.mplayerhq.hu/

xine can also play your video for you. It also handles most of the popular formats used these days, is skinnable (Oooh! Skinnable!) and features a sourceforge page with a very nice screenshot of it playing Tomb Raider. The xine is generally called with a graphical toolbar thing, so you can click on things instead of using commandline options, and it can also use the Xv drivers. If you have something to say about xine, ogle, or other video players, please interject those during our presentation.

To find out more about xine, take a look at http://xine.sourceforge.net/