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  2:1 downsampling: (stereo)    42%
                    (singlemix) 21%

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Description:

This isn't a new player. It's a fully rewritten version originally based 
on the dist10/mpegaudio (FHG-version) package. The DCT algorithm in the
synthesis filter is a rewritten version of the DCT first seen in the maplay
package, which was written by Tobias Bading (bading@cs.tu-berlin.de). The 
rewrite was neccassary, because the GPL may not allow this copyright mix.
The mpegaudio package was written by various people from the MPEG/audio
software simulation group. The maplay is under GPL .. You can find the
original source code and the mpegaudio package on: ftp.tnt.uni-hannover.de.

Especially layer3.c common.c and mpg123.h is based on the dist10 package.
The code is fullly rewritten but I'm using sometimes the
same variable names or similar function names as in the
original package.

In the current layer3.c I'm using a DCT36 first seen in Jeff Tsay's 
(ctsay@pasteur.eecs.berkeley.edu) maplay 1.2+ package. His code is
under GPL .. I also tried the enhancement from Mikko Tommila. His
code is also in layer3.c (but it's disabled at the moment, because
it was slightly slower than the unrolled 9 point DCT (at least on 
_my_ system)). Theoretically it should be faster. You may try it on
your system.

The output can converted to different audio formats and
rates. Currently, only (very simple) audiosupport for
the most common computer systems. It's possible
to build a 'generic' version which needs an external
audio player for playing.

I have tested the program with a lot of teststreams, but it's very 
likely, that there are still a few bugs.

Playing MP3s coming with MIMEType "audio/x-mpegurl" 
---------------------------------------------------
For netscape navigator: 
Go: Preferencs->Navigator->Applications
 Click 'NEW' Button and fill in the form:
  Description: MP3 Playlist
  MIMEType:    audio/x-mpegurl
  suffix:      m3u
 Click the 'Application' button below and add a
  mpg123 -@ %s
 or maybe better
  xterm -e mpg123 -@ %s
 in the application field. Press OK. That's all.


NAS notes: (from Martin Denn)
-----------------------------
you may wanna play with the following defines: (from audio.c)
  NAS_SOUND_PORT_DURATION 
  NAS_SOUND_LOW_WATER_MARK
Change them to optimize the player for your environment. For slow
networks a proven config is:
#define NAS_SOUND_PORT_DURATION 10 /* seconds */
#define NAS_SOUND_LOW_WATER_MARK 75 /* percent */

Pentium optimization notes:
---------------------------
The ASM optimaztions are especially for Intel Pentium FPUs.
On other processorts the egcs compiler optimization
may do a better job. This part can be used under GPL.

3DNow notes:
------------
You need a new 'as'. ie. the 'as' from binutils-2.9.1.0.19a.
If you don´t have a suitable ´as´, you may wanna try to _copy_ the
files dct64_3dnow.o and decode_3dnow.o from the precompiled/ 
directory to the base mpg123 source path and try to compile
the source.
A funny side-effect of the 3dnow optimizations is, that now the
-2 and -4 downsampling is a little slower than full quality, because
the 3dnow optimization is only enabled for full quality decoding.
3dnow only works with -DREAL_IS_FLOAT. 

License Change:
---------------
It is possible to use the raw decoder under GPL. 
(please note: the use under GPL may be restricted by patents in some countries!)
Currently, 'the raw decoder' means the following files: 
  layer1.c, layer2.c, layer3.c, decode.c, dct64.c, decode_i386.c, dct64_i386.c,
  decode_i586.s, decode_2to1.c, decode_4to1.c, getbits.c, getbits.h, mpg123.h,
  tabinit.c, l2tables, huffman.h

----------------------------------------------------------------------------

And now have fun,
           Mike

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Just for info:
    I'm also working (but not at the moment) on a DSP port for this package. 
    A first testversion of the _LAYER-2_ part is finished and seems
    to work in realtime with my 20MHZ ADSP-2115 

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Copyrights (c) 1995,1996,1997,1998,1999,2000 of all changes/modifications and
of the new code by Michael Hipp. All rights reserved.
Copyrights (c) 1997 of several enhancements by Oliver Fromme.
See the packages 'maplay 1.2(+)' and 'mpegaudio' for their copy-policies.
Copyrights (c) 1997 of the OS2 specific parts by Niclas Lindstrom

known bugs:
-----------
  layer 3 i-stereo not heavily tested
   btw: I'm looking for i-stereo teststreams .. maybe you could send me a few
  Layer 1 not heavily tested
  no CRC checking ..
  no 'free format streams'
  no clean audio interface
  MPEG 2.0, Layer1 and Layer2 not tested (and probably will not work)
  MPEG 2.0, Layer3 not heavily tested .. may has bugs.

related information: