Manual.txt for Version 1.50 of ISO/MPEG Audio Layer 3 software only 
encoder/decoder for PCs.

1. ENCODER V1.00
   =============

 L3ENC.EXE is an ISO/MPEG Layer III software only encoder. It takes 
 PCM audio data files as input and delivers Layer III coded bit stream 
 files as output. Several options can be selected via command line 
 switches. Usage:
 
   L3ENC <PCM audio data> <bitstream> [-switch1 [-switch2 [...]]]

 L3ENC.EXE should work on any IBM PC compatible computer with a 386 type 
 CPU or better with external or built in 387 hardware floating point 
 support. A 486DX CPU or better is recommended.

 L3ENC uses one of the Dos extenders EMX.EXE or RSX.EXE supplied together 
 with this shareware package. EMX.EXE is used for Dos Real Mode and RSX.EXE
 is used for V86 Mode (e.g. Dos Box under Windows). L3ENC automatically 
 loads the appropriate extender when started. In order to find the extender, 
 L3ENC needs emx.exe and rsx.exe in the same directory or the environment 
 variables EMX and RSX. If you place emx.exe  or rsx.exe not in the same
 directory as l3enc.exe please execute the commands:
   SET EMX=C:\PATH\EMX.EXE
   SET RSX=C:\PATH\RSX.EXE
 where "C:\PATH\" shows the directory where EMX.EXE and RSX.EXE can be found.
 
 EMX.EXE is copyright by Eberhard Mattes and RTX.EXE is copyright by
 Rainer Schnither. Please read the documentation supplied with the 
 dos extenders for details.

1.1 PCM audio input file
 The first command line argument specifies the name for the PCM audio
 data file. Version 1.00 of the encoder accepts either raw PCM audio 
 data files or PCM audio data files in RIFF/WAVE format as used by
 Microsoft Windows. The samples must be 16 bit signed integer values.
 The sampling rate must be 44.1 kHz.
   
 A) raw PCM audio data
    By default the input file is assumed to contain raw PCM audio data.
    Stereo audio data is input in interleaved format, the first channel
    beeing the left channel.
      <sample #1 channel #1> <s. #1 ch. #2> <s.#2 ch.#1> <s.#2 ch.#2> ...
    Mono audio data has the format
      <sample #1> <sample #2> <sample #3> ....
    Whether the input file is treated as mono or stereo audio data is set
    by the encoding mode parameter (1.3). Default is stereo.

 B) RIFF/WAVE format
    If the '-wav' option is specified, the input file is assumed to contain
    16 bit PCM audio data in RIFF/WAVE format as used by Microsoft Windows.
    Audio parameters are extracted from the Wave header and checked against
    the settings of the encoder. If not supported options are found 
    (e.g. 8 bits/sample), the encoding process is aborted. The encoding
    mode (mono or stereo) is determined by the settings in the WAVE header.

1.2 bitstream output file
 The second command line argument specifies the name for the bitstream 
 output file. As for now there is no default value for the filename or for 
 the extension of the file name. The format of the bit stream is as defined 
 in the ISO/MPEG publication IS11172-3.

1.3 encoding mode
 Depending on the setting of the '-mod' switch, the encoder will treat the 
 two input channels as:
	-mod 1  stereo (joint stereo),
	-mod 2  mono audio data.

 Default is joint stereo. 
 For stereo, the first channel is the left channel. The second channel is 
 the right channel.

 If input files in WAVE format are used, the encoding mode is determined by
 the settings in the Wave header.

1.4 sampling rate
 Version 1.00 of the encoder is still restricted to 44.1 kHz.
 Look for support of 32kHz, 44.1 kHz and 48 kHz in the near future.

1.5 bitrate
 The bitrate of the bit stream output is selected via the '-br' switch.  The 
 bitrate is specified in bits/second. The bitrate is the total bitrate for 
 all encoded channels, i.e. if you select 'br 128000' and 'stereo', both 
 channels will be stuffed into one bit stream of 128000 bits/second. 
 Currently only ISO bit rates are accepted by the encoder. Valid bit rates 
 are:

 32k  40k  48k  56k  64k  80k  96k  112k  128k  160k  192k  224k  256k  320k   

 The default bitrate is 128000 bits/sec.

 Version 1.00 of the encoder is restricted to stereo bit rates greater 
 than 64 kBit/s and to mono bit rates less than 320 kBit/s. 

1.6 crc check
 If '-crc' is asserted, ISO/MPEG1 crc checking is enabled. Without the 'crc' 
 switch, crc checking is disabled.

1.7 swap low and high byte of input samples
 If the '-tfs' option is specified, the low and high bytes of each audio
 data input sample are swapped. Use '-tfs' if you move your PCM audio data
 from little endian to big endian machines (or vice versa).

1.8 examples of switch settings
    L3ENC infile.pcm out.bit -br 112000 -cr
    L3ENC c:\music\pcm\newage.pcm c:\bitstr\l3\newage.bit -mod 2 -br 64000
    L3ENC pop.wav -wav -br 96000


