alsa-tools/ac3dec/README
2001-04-17 19:31:03 +00:00

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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