DelfMPEG 1.1

MPEG audio player for Delfina DSP

Short:        MPEG audio player for Delfina DSP
Author:       smack42@web.de (Michael Henke)
Uploader:     smack42 web de (Michael Henke)
Type:         mus/play
Version:      1.1
Architecture: m68k-amigaos >= 2.0.4

DelfMPEG 1.1 (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

  -can write the decoded audio data to a file

  -ARexx interface
   (full 'remote control' capability)

  -multi-stage buffering system
   (for smooth playback while loading from disk)

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



#required

  -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

  -latest version of delfina.library (see also 'known problems' section)
  -some MPEG audio files :)



#changes since previous release

  - do not use asyncio.library anymore, AsyncIO is now statically linked
  - do not use reqtools.library anymore, use ASL file requesters instead
  - do not overwrite any existing files when using option OUTFILE
  - display Delfina supported audio frequencies in VERBOSE mode
  - changed the default FFSKIP value to 40, which is about one second
  - improved duration estimation by subtracting any skipped file headers
  - mp2 and mp3 decoders are slightly faster and a tiny bit more accurate



#how to use

  DelfMPEG is a shell-only program.  The following options can be used:

  FILES ......... -one or more filenames. (MPEG files or playlists)
                  -if omitted a file requester appears.
                  -if a file is not recognized as MPEG-1 audio then it is
                   interpreted as a playlist file. playlists are simple text
                   files that can be generated by popular player programs,
                   such as AMPlifier, Winamp (*.m3u) and others.
                  -playlist format: one file name per line, comment lines
                   beginning with a '#' character are ignored.

  OUTFILE/-o <filename>
                  -write decoded data to this file (no playback).
                  -output file format: raw PCM (no AIFF or WAV header),
                   16 bits per sample (big endian),
                   number of channels (1=mono or 2=stereo) and sampling
                   frequency (32000, 44100 or 48000 Hz) are taken from the
                   MPEG input file.
                  -note: you can use DelfSF to play the raw file.
                   (Aminet:mus/play/DelfSF.lha)

  OUTFILEINTEL/-oi <filename>
                  -same as OUTFILE, except that the output data is written
                   in Intel byteorder (little endian).
                  -note: you can use DelfSF to play the raw file.
                   (Aminet:mus/play/DelfSF.lha)

  AREXX ......... -activate ARexx mode.
                  -please read the file 'arexx.txt' for details.
                  -there are some example scripts in the 'rexx' sub-directory

  VERBOSE/-v .... -output more information.

  NOPLAY/-n ..... -don't play but just output some information.
                  -this works also without a Delfina board.

  SHOWTAG/-t .... -display ID3v1 tag before playing.
                  -some extra information that can be appended to MPEG audio
                   files, such as title, artist etc.

  MONO/-m ....... -decode only the left channel of stereo files.
                  -WARNING: degrades playback quality!
                  -this option can be used to reduce DSP load on Delfina Lite
                   boards which have a slower DSP (40 MHz instead of 73 MHz)

  DACRATE/-d <number>   (default: 0)
                  -set Delfina's codec rate to a fixed value (in kHz).
                  -WARNING: can degrade playback quality!
                  -this option can be used to reduce DSP load on Delfina Lite
                   boards which have a slower DSP (40 MHz instead of 73 MHz)
                  -the default value of 0 (zero) means "best quality"
                  -the given value is automatically rounded to the nearest
                   available Delfina rate:  16, 27, 32 or 48 kHz.
                   (for Delfina 1200 and Plus: 12, 24, 36 or 48 kHz)

  VOLUME/-vol <number>  (default: 100)
                  -set the playback volume (in per cent, range 0...200).
                  -WARNING: can degrade playback quality!
                   if the volume is boosted (101...200) there can be
                   distortions caused by output clipping.

  FRAMEBUF/-f <number>  (default: 100)
                  -set the number of read-ahead frame buffers.
                   (does not influence performance)

  ASYNCBUF/-a <number>  (default: 128)
                  -set the size of the AsyncIO buffer (in Kbytes).
                   (large IO-buffers = faster reading from disk)

  FFSKIP/-ff <number>   (default: 40)
                  -set the number of frames that are skipped during fast
                   forward mode, i.e. when Ctrl-F is pressed

  NOFASTL/-nl
  NOFASTP/-np ... -the fast internal DSP memory is NOT used (L-data/Program)
                  -only useful for benchmarks or debugging

  NOTIMER/-nt ... -suppress output of the position timer during playback.
                   (recommended for playing background music while you are
                   using other programs)

  STRICT/-s ..... -abort playback when an error in input file is detected.
                   (normally DelfMPEG tries to continue playback by skipping
                   the error in the file)


  During playback these keys can be used:

  Ctrl-F   fast forward
  Ctrl-E   pause/continue
  Ctrl-C   stop current file, start next file
  Ctrl-D   quit program



#known problems

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

  -some mp3 files are not played correctly! what's wrong with DelfMPEG?

   1) DSP load approaches or exceeds the 100% limit on slow Delfinas.
      symptom: audible "drop-outs", DECODER_BUSY warning in VERBOSE mode.
      actions: use MONO or DACRATE options to reduce DSP load (and quality)
               or overclock your Delfina Lite (by hardware modification or
               software hack "DelfTweak") or buy a new, faster Delfina.

   2) in VERBOSE mode an "unexpected EOF" error is reported for some files.
      symptom: just the error message.
      actions: this seems to be caused by some (bad) MPEG audio encoders that
               truncate the last frame in mp3 files. use LAME instead, it's
               the best mp3 encoder around, IMO.

  -DelfMPEG 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



#acknowledgements

  DelfMPEG 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)



#author

  mailto: smack42@web.de

  DelfMPEG - MPEG audio player for Delfina DSP
  Copyright (C) 1999-2026  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/>.