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2001-07-04
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Short: Mpeg.device for Delfina DSP
Author: Smack/Infect! (Michael Henke)
Type: mus/play
$VER: delfinampeg.device 1.3 (Thu 14-Jun-2001)
#features
-plays MPEG audio files with almost no CPU load
(Delfina's DSP56002 does all the decoding and playback)
-standard "mpeg.device" API
(code based on melodympeg.device by Thorsten Hansen)
-free software
(full source code included, of course)
#requirements
-CPU 68020+
-Delfina DSP board
#changes since previous release
-new email address
-little code optimizing
-fixed a quite unobvious bug in the cleanupDelfina() routine
this avoids the "noisy deadlock" when seeking inside a file in AMPlifier
using delfina.library 4.14 (personally, I can tolerate the "fake crash"
bug of 4.14 but I *hate* the "sudden freeze" problem of the 4.16ß libs)
#how to use it
Copy delfinampeg.device to your "devs:" drawer and configure an application
program to make use of it, for instance:
AMPlifier http://www.katodev.de
Configuration -> Audio I/O -> MPEG audio player -> Decoder
MPEG device: delfinampeg.device
Unit: 0
Buffersize: 128 (recommended, use any value you want)
Blocksize: 16 (recommended, use any value you want)
set Layer I/II and Layer III to "Hardware" decoding
Frogger http://frogger.rules.pl
use the option ADECODER with mode DELFINA
AmigaAMP http://www.amigaamp.de
get the "MHI driver for mpeg.device" from Aminet: mus/play/mhimdev.lha
follow the installation instructions in the README file
Especially owners of the slower Delfinas (i.e. Lite) might be interested
in the configuration options of delfinampeg.device, which can be used to
sacrifice some playback quality in order to reduce DSP load. The device
reads them from the environment variable DELFINAMPEG during OpenDevice().
The options are:
L2MONO...........mp2 files: decode left channel only
L2RATE <number>..mp2 files: play at specified rate (given in kHz)
L3MONO...........mp3 files: decode left channel only
L3RATE <number>..mp3 files: play at specified rate (given in kHz)
The given playback rate is automatically rounded to the nearest available
Delfina rate (16, 27, 32, 48 kHz; Delfina 1200/Plus: 12, 24, 36, 48 kHz).
example:
> setenv DELFINAMPEG l3rate 32 l2mono
(play mp3 files at 32 kHz, force mp2 decoding to mono)
> copy ENV:DELFINAMPEG ENVARC:
(save settings to disk)
#known problems
-use the latest (beta?) delfina.library - the README of DelfMPEG contains
a list of known bugs in the library.
-the MPEG decoding routines are taken from DelfMPEG, so the same
restrictions apply here:
-only MPEG-1 layer II and III audio files are supported.
-the decoding routines need a lot DSP processing power, especially
mp3 playback might overburden the slower Delfinas (i.e. Lite).
try the config options listed above if you get "stuttering" sound,
because that can be the result of the DSP decoding data too slowly.
-equalizer and visual effect plugins of AMPlifier are currently not
supported. this is not a feature of the mpeg.device. AMPlifier needs to
copy the decoded audio data back from the sound board to main memory,
which it can only do with the Melody boards but not (yet) with Delfina.
#acknowledgements
delfinampeg.device uses ideas/code from:
-MPEG Audio Layer II decoder by Fredrik Noring and Tomas Berndtsson
(an mp2 player for Atari Falcon, DSP56K code)
-amp11 by Niklas Beisert (clean and fast C++ code)
-FalcAMP by Denis "STGhost" Huguet and David "Splash" Carrere
(an mp3 player for Atari Falcon, DSP56K code)
-reference code by MPEG Software Simulation Group ("the original" C code)
-melodympeg.device by Thorsten Hansen
#author
mailto: smack42@web.de
delfinampeg.device - mpeg.device for Delfina DSP
Copyright (C) 2000, 2001 Michael Henke
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
============================= Archive contents =============================
Original Packed Ratio Date Time Name
-------- ------- ----- --------- -------- -------------
18113 7000 61.3% 14-Jun-01 13:31:40 +COPYING
84480 47182 44.1% 14-Jun-01 13:31:40 +delfinampeg.device
4731 2255 52.3% 14-Jun-01 13:31:40 +README
1355 776 42.7% 14-Jun-01 13:31:40 +CHANGES
23750 6296 73.4% 14-Jun-01 13:31:40 +delfinampeg.c
15396 5217 66.1% 14-Jun-01 13:31:40 +device.asm
63142 12635 79.9% 14-Jun-01 13:31:40 +MP2.a56
1422 677 52.3% 14-Jun-01 13:31:40 +MP2.h
82475 22466 72.7% 14-Jun-01 13:31:40 +MP3.a56
1553 723 53.4% 14-Jun-01 13:31:40 +MP3.h
82305 29467 64.1% 14-Jun-01 13:31:40 +MP3_pow43tab.h
5178 1093 78.8% 14-Jun-01 13:31:40 +MP3_quantab.h
3589 1607 55.2% 14-Jun-01 13:31:40 +PCM.a56
1367 649 52.5% 14-Jun-01 13:31:40 +PCM.h
164 123 25.0% 14-Jun-01 13:31:40 +SCOPTIONS
385 150 61.0% 14-Jun-01 13:31:40 +smakefile
-------- ------- ----- --------- --------
389405 138316 64.4% 16-Jun-101 10:20:28 16 files