decode.c

mp3 source code decoder & encoder

/**********************************************************************
 * ISO MPEG Audio Subgroup Software Simulation Group (1996)
 * ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension
 *
 * $Header: /MP3Stego/MP3Stego Decoder/decode.c 5     30/10/98 11:24 Fapp2 $
 *
 * $Id: decode.c,v 1.2 1996/03/28 03:13:37 rowlands Exp $
 *
 * $Log: /MP3Stego/MP3Stego Decoder/decode.c $
 * 
 * 5     30/10/98 11:24 Fapp2
 * 
 * 4     15/08/98 10:40 Fapp2
 * Started revision control on this file.
 * Revision 1.2  1996/03/28 03:13:37  rowlands
 * Merged layers 1-2 and layer 3 revisions
 *
 * Revision 1.1  1996/02/14 03:45:52  rowlands
 * Initial revision
 *
 * Received from FhG
 **********************************************************************/
/**********************************************************************
 *   date   programmers         comment                               *
 * 2/25/91  Douglas Wong,       start of version 1.0 records          *
 *          Davis Pan                                                 *
 * 3/06/91  Douglas Wong        rename: setup.h to dedef.h            *
 *                                      dfilter to defilter           *
 *                                      dwindow to dewindow           *
 *                              integrated "quantizer", "scalefactor" *
 *                              combined window_samples routine into  *
 *                              filter samples                        *
 * 3/31/91  Bill Aspromonte     replaced read_filter by               *
 *                              create_syn_filter and introduced a    *
 *                              new Sub-Band Synthesis routine called *
 *                              SubBandSynthesis()                    *
 * 5/10/91  Vish (PRISM)        Ported to Macintosh and Unix.         *
 *                              Changed "out_fifo()" so that last     *
 *                              unfilled block is also written out.   *
 *                              "create_syn_filter()" was modified so *
 *                              that calculation precision is same as *
 *                              in specification tables.              *
 *                              Changed "decode_scale()" to reflect   *
 *                              specifications.                       *
 *                              Removed all routines used by          *
 *                              "synchronize_buffer()".  This is now  *
 *                              replaced by "seek_sync()".            *
 *                              Incorporated Jean-Georges Fritsch's   *
 *                              "bitstream.c" package.                *
 *                              Deleted "reconstruct_sample()".       *
 * 27jun91  dpwe (Aware)        Passed outFile and &sampFrames as     *
 *                              args to out_fifo() - were global.     *
 *                              Moved "alloc_*" reader to common.c.   *
 *                              alloc, sblimit, stereo passed via new *
 *                              'frame_params struct (were globals).  *
 *                              Added JOINT STEREO decoding, lyrs I&II*
 *                              Affects: decode_bitalloc,buffer_samps *
 *                              Plus a few other cleanups.            *
 * 6/10/91   Earle Jennings     conditional expansion added in        *
 *                              II_dequantize_sample to handle range  *
 *                              problems in MSDOS version             *
 * 8/8/91    Jens Spille        Change for MS-C6.00                   *
 *10/1/91    S.I. Sudharsanan,  Ported to IBM AIX platform.           *
 *           Don H. Lee,                                              *
 *           Peter W. Farrett                                         *
 *10/3/91    Don H. Lee         implemented CRC-16 error protection   *
 *                              newly introduced functions are        *
 *                              buffer_CRC and recover_CRC_error.     *
 * 2/11/92  W. Joseph Carter    Ported new code to Macintosh.  Most   *
 *                              important fixes involved changing     *
 *                              16-bit ints to long or unsigned in    *
 *                              bit alloc routines for quant of 65535 *
 *                              and passing proper function args.     *
 *                              Removed "Other Joint Stereo" option   *
 *                              and made bitrate be total channel     *
 *                              bitrate, irrespective of the mode.    *
 *                              Fixed many small bugs & reorganized.  *
 * 7/27/92  Juan Pineda         Bug fix in SubBandSynthesis()         *
 *--------------------------------------------------------------------*
 * 6/14/92  Juan Pineda         Layer III decoding routines added.    *
 *          Amit Gulati         Follows CD 3-11172 rev2.  Contains    *
 *                              hacks deal with evolving available    *
 *                              layerIII bitstreams.  Some (minor)    *
 *                              modification of prior LI&II code.     *
 * 10/25/92 Amit Gulati         Updated layerIII routines. Added code *
 *                              for subblock_gain, switched block     *
 *                              modes, stereo pre-processing.         *
 *                              Corrected sign bits for huffman       *
 *                              decoding of quadruples region and     *
 *                              adjusted gain factor in III_dequant.  *
 * 11/21/92 Amit Gulati         Several layerIII bugs fixed.          *
 * 12/15/92 Amit Gulati         Corrected reordering (indexing)       *
 *          Stan Searing        within IMDCT routine.                 *
 *  8/24/93 Masahiro Iwadare    Included IS modification in Layer III.*
 *                              Changed for 1 pass decoding.          *
 *  9/07/93 Toshiyuki Ishino    Integrated Layer III with Ver 3.9.    *
 *--------------------------------------------------------------------*
 * 11/20/93 Masahiro Iwadare    Integrated Layer III with Ver 4.0.    *
 *--------------------------------------------------------------------*
 *  7/14/94 Juergen Koller      Bug fixes in Layer III code           *
 *--------------------------------------------------------------------*
 * 08/11/94 IIS                 Bug fixes in Layer III code           *
 *--------------------------------------------------------------------*
 * 9/20/94  Davis Pan           Modification to avoid premature       *
 *                              synchword detection                   *
 *--------------------------------------------------------------------*
 * 11/09/94 Jon Rowlands        Merged premature synchword detection  *
 *                              fix into layer III code version       *
 *--------------------------------------------------------------------*
 * 07/12/95 Soeren H. Nielsen   Changes for LSF Layer I and II        *
 *--------------------------------------------------------------------*
 *    8/95  Roland Bitto	    Adapted to MPEG2                      *
 *  9/8/95  Roalnd Bitto        Bugfix in Function III_stereo         *
 *--------------------------------------------------------------------*
 *  Aug 98  Fabien Petitcolas   Add stego stuff                       *
 **********************************************************************/

#include "common.h"
#include "decoder.h"
#include "huffman.h"

#include "../stegolib/stego.h"

/***************************************************************
/*
/* This module contains the core of the decoder ie all the
/* computational routines. (Layer I and II only)
/* Functions are common to both layer unless
/* otherwise specified.
/*
/***************************************************************/

/*****************************************************************
/*
/* The following routines decode the system information
/*
/****************************************************************/

/************ Layer I, Layer II & Layer III ******************/


//=======================================================
// Function name: 	decode_info
// Author:        
// Date:          2002/3/16
// Description:   decode the Frame information
// Input:         *bs    --- point to Bit_stream_struc 
//                *fr_ps --- point frame_params 
// Return value:  
// Notes: