INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION ISO/IEC JTC1/SC29/WG 11 CODING OF MOVING PICTURES AND ASSOCIATED AUDIO MPEG92/ Nov. 1992 Source: Davis Pan (Digital Equipment Corporation), Chairman of the MPEG/audio ad hoc committee on software simulation Title: Working Draft of MPEG/Audio Technical Report Disclaimer of Warranty These software programs are available to the user without any license fee or royalty on an "as is" basis. ISO disclaims any and all warranties, whether express, implied, or statuary, including any implied warranties or merchantability or of fitness for a particular purpose. In no event shall ISO be liable for any incidental, punitive, or consequential damages of any kind whatsoever arising from the use of these programs. This disclaimer of warranty extends to the user of these programs and user's customers, employees, agents, transferees, successors, and assigns, ISO does not represent or warrant that the programs furnished hereunder are free of infringement or any third-party patents, copyrights or trade secrets. The purpose of this software is to provide a tool to help in the learning and understanding of the MPEG/audio compression and decompression algorithm. It is not an efficient implementation. Organization of this Report The main body of this report describes the organization and use of the software. The listings of the software, sample makefiles, and test bitstreams are contained in the appendices: Appendix A contains the source code for the MPEG/audio software, written in the C programming language. This software has been run and verified a large variety of computers and operating systems. Appendix B contains sample "makefiles" which can be used to compile the software. Before compiling, please examine the file common.h to determine if any of the "#define" declarations should be reactivated by removing it from a comment statement. Appendix C contains a minimal bitstream test that can be used to verify the proper operation of the MPEG/audio software. The bitstream test consists of three bitstreams: orig.mpg - The original, coded MPEG/audio bitstream deco.dec - The audio data resulting from decoding orig.mpg renc.dec - The encoded MPEG/audio bitstream obtained by encoding deco.dec The software is functioning properly if the following equations hold: a. decoded(orig.mpg) == deco.dec byte-swapping of deco.dec will be necessary for this equation to hold for little-endian computers b. encoded(deco.dec) == renc.mpg (encode with the default options except for the following: 48 kHz sampling rate and 256 kbits/sec coded bit rate) If the bitstream tests fail, make sure that the following variable types have at least the precision listed below: integer - 16 or 32bits float - 32 bits double - 64 bits. Electronic Distribution All the data listed above may be obtained in electronic form (e-mail) by contacting : Mr. Frank Laczko tel: 214-997-3988 FAX: 214-997-5763 e-mail: frank@laczko.ti.com Other electronic distribution methods may become available soon. Managers of public access FTP sites are encouraged to make this software available on their sites. Organization of the Code The MPEG/audio Layer 1 and Layer 2 ** software package consists of: 21 data files tables 8 source files (*.c) 3 definitions files (*.h) 3 test bitstreams * makefiles ** The layer 3 software is currently work in progress and will be included in a future revision of this report. Table 1 illustrates how the encoder and decoder is formed from the component files. In this table the definition files are enclosed in parenthesis and listed immediately below the primary source file which uses them. The data file names are listed within braces and also placed immediately below the source file which uses them. Table 1 encoder common decoder files files files ---------- ------------ ------------ musicin.c common.c musicout.c encode.c (common.h) decode.c (encoder.h) {alloc_0} (decoder.h) {enwindow} {alloc_1} {dewindow} psy.c, subs.c {alloc_2} {absthr_0} {alloc_3} {absthr_1} {absthr_2} tonal.c {1cb0}, {1cb1}, {1cb2} {2cb0}, {2cb1}, {2cb2} {1th0}, {1th1}, {1th2} {2th0}, {2th1}, {2th2} Running the Software To run this software, compile the programs to form an encoder executable file, musicin, and a decoder executable file, musicout. To run the code type the name of the file followed by a carriage return. The programs will prompt you to input the appropriate parameters. The sound input file for the encoder should be sound data, monophonic or stereophonic, sampled at 32, 44.1, or 48 kHz with 16 bits per sample. For stereophonic data the left channel sample should precede the right channel sample. The sound output file of the decoder will be the same format as the sound input file used by the decoder, except for possible byte order differences if the encoder and decoder programs are run on different computer systems which have different byte ordering conventions. Special notes for MSDOS users: 1. The default bitrate option does not work. 2. The input/output filename defaults not compatible with MSDOS. 3. Use the large memory model for compilation. Notes on the Software The encoder and decoder software are configured to output the coded audio bitstreams as a string of hexadecimal ascii characters. For greater compression efficiency, compile flag, BS_FORMAT, in common.h can be switched to configure the bitstream reading and writing routines to process raw binary bitstreams. The decoder program has a very crude implementation of bitstream synchword detection. It may not be able to correctly decode valid bitstreams which have false synchword patterns in the ancillary data portion of the bitstream. Appendix A MPEG/audio Source Code (included elsewhere) Appendix B Sample "makefiles" (included elsewhere) Appendix C Test Bitstreams (included elsewhere) Appendix D List of Contributors Bill Aspromonte Shaun Astarabadi R. Bittner Karlheinz Brandenburg W. Joseph Carter Jack Chang Mike Coleman Johnathan Devine Ernst Eberlein Dan Ellis Peter Farrett Jean-Georges Fritsch Vlad Fruchter Hendrik Fuchs Bernhard Grill Amit Gulati Munsi Haque Chuck Hsiao Toshiyuki Ishino Masahiro Iwadare Earl Jennings James Johnston Leon v.d. Kerkhof Don Lee Mike Li Yu-Tang Lin Soren Neilsen Simao F. Campos Neto Mark Paley Davis Pan Tan Ah Peng Kevin Peterson Juan Pineda Ernst F. Schroeder Peter Siebert Jens Spille Sam Stewart Al Tabayoyon Kathy Wang Franz-Otto Witte Douglas Wong