alsa-tools/ac3dec

ac3dec - a free AC-3 stream decoder

Written by Aaron Holtzman (aholtzma@engr.uvic.ca)

Contributors:
  Michael Holzt <kju@flummi.de> - OSS output.c and misc errata
	Jim Miller <jmiller@heli.engr.sgi.com> - IRIX output.c
	Angelos Keromytis <angelos@dsl.cis.upenn.edu> - OpenBSD fixes
	Don Mahurin <dmahurin@dma.org> - stdin support for extract_ac3
	Takefumi SAYO <stake@niagara.shiojiri.ne.jp> - FreeBSD tweak
	Charles M. Hannum <root@ihack.net> - fixes


See the file COPYING for license details.

The currently supported platforms are Linux, Solaris, IRIX, OpenBSD, and
FreeBSD. If you want support for other platforms, take a look at 
output_*.c for an idea of what you need to do.

This software is completely useless to 99.99 percent of users
out there. It is mostly of use to those interested in audio
coding research and evaluating codecs. It could theoretically
be used as a portion of a DVD playback system for unix systems. 

HOW TO COMPILE

Building ac3dec should be easy. Here's how:

./configure && make all

USAGE

To find AC-3 streams on the internet, use www.google.com and 
search for "vob trailer". A vob is a "Video Object" which is
just an MPEG-2 stream. The site www.hollywood.com has a 
few good MPEG-2s with AC-3 audio. The program tools/extract_ac3 
will take an MPEG-2 stream and spit out AC-3 audio to stdout if
it exists. You can easily pipe this data to the ac3 player like
this:

  ./tools/extract_ac3 foo.vob | ./ac3dec/

You can also get AC-3 streams on a DVD. Check out 
http://www.linuxvideo.org for details.

DEBUG OUTPUT

You can get a whole pile of debug info by setting the environment
variable AC3_DEBUG=1. Be sure to pipe stderr to a file or you probably
won't get realtime playback. You can pipe stderr to a file like so:

  ./ac3dec foo.ac3 2> debug.out