dmdev 1.7

mpeg.device for Delfina DSP

Short:        mpeg.device for Delfina DSP
Author:       smack42@web.de (Michael Henke)
Uploader:     smack42 web de (Michael Henke)
Type:         mus/play
Version:      1.7
Architecture: m68k-amigaos >= 2.0.4

delfinampeg.device 1.7 (2026-08-23)



#features

  -plays MPEG audio files with almost no CPU load
   (Delfina's DSP56002 does all the decoding and playback)

  -supports MPEG-1 layer II and III

  -standard "mpeg.device" API
   (code based on melodympeg.device by Thorsten Hansen)

  -free software
   (full source code included, of course)



#requirements

  -CPU 68020+
  -AmigaOS V37+
  -Delfina DSP board

  -developed on A1200 - OS3.2/68030+882@40MHz/16MBFastRAM/Delfina1200DSP
  -tested on various machines with Delfina 1200, Lite, Plus or Flipper



#recommended

  -application that uses mpeg.device (such as AMPlifier, Frogger and others)
  -some MPEG audio files :)



#changes since previous release

  - mp2 and mp3 decoders are slightly faster and a tiny bit more accurate



#how to use

  Copy delfinampeg.device to your "devs:" drawer.
  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)
      Blocksize:      16  (recommended)
      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
    (play mp3 files at 32 kHz)
  > copy ENV:DELFINAMPEG ENVARC:
    (save settings to disk)



#known problems

  -delfinampeg.device only recognizes MPEG-1 audio files.
   not supported: MPEG-2 or mixed audio/video files.

  -delfinampeg.device causes deadlocks/crashes.

   1) for the Petsoff Delfinas (Classic, Lite, Plus, 1200)
      it seems that the most stable driver is still this inofficial version:
      delfina.library 4.16 ß 3 PATCH#2 14-Oct-2001

   2) for the Delfina Flipper by Individual Computers
      use the latest driver (delfina.library) that is available
      at the vendor site:  https://wiki.icomp.de/wiki/Delfina
      or you can ask in an Amiga forum if there are any further developments of
      the open source driver software

  -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 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) 2000-2026  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, see <https://www.gnu.org/licenses/>.