mirror of
https://github.com/cookiengineer/audacity
synced 2025-10-31 14:13:50 +01:00
5e0efd1a25
Using LAME 3.10 Windows project files substantially changed from original, and included into audacity solution.
233 lines
7.3 KiB
C
233 lines
7.3 KiB
C
/*
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* layer1.c: Mpeg Layer-1 audio decoder
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*
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* Copyright (C) 1999-2010 The L.A.M.E. project
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*
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* Initially written by Michael Hipp, see also AUTHORS and README.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/* $Id: layer1.c,v 1.31 2017/08/23 13:22:23 robert Exp $ */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <assert.h>
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#include "common.h"
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#include "decode_i386.h"
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#ifdef WITH_DMALLOC
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#include <dmalloc.h>
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#endif
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#include "layer1.h"
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static int gd_are_hip_tables_layer1_initialized = 0;
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void
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hip_init_tables_layer1(void)
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{
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if (gd_are_hip_tables_layer1_initialized) {
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return;
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}
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gd_are_hip_tables_layer1_initialized = 1;
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}
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typedef struct sideinfo_layer_I_struct
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{
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unsigned char allocation[SBLIMIT][2];
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unsigned char scalefactor[SBLIMIT][2];
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} sideinfo_layer_I;
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static int
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I_step_one(PMPSTR mp, sideinfo_layer_I* si)
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{
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struct frame *fr = &(mp->fr);
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int jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;
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int i;
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int illegal_value_detected = 0;
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unsigned char const ba15 = 15; /* bit pattern not allowed, looks like sync(?) */
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memset(si, 0, sizeof(*si));
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assert(fr->stereo == 1 || fr->stereo == 2);
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if (fr->stereo == 2) {
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for (i = 0; i < jsbound; i++) {
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unsigned char b0 = get_leq_8_bits(mp, 4); /* values 0-15 */
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unsigned char b1 = get_leq_8_bits(mp, 4); /* values 0-15 */
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si->allocation[i][0] = b0;
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si->allocation[i][1] = b1;
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if (b0 == ba15 || b1 == ba15)
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illegal_value_detected = 1;
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}
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for (i = jsbound; i < SBLIMIT; i++) {
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unsigned char b = get_leq_8_bits(mp, 4); /* values 0-15 */
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si->allocation[i][0] = b;
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si->allocation[i][1] = b;
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if (b == ba15)
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illegal_value_detected = 1;
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}
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for (i = 0; i < SBLIMIT; i++) {
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unsigned char n0 = si->allocation[i][0];
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unsigned char n1 = si->allocation[i][1];
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unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
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unsigned char b1 = n1 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
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si->scalefactor[i][0] = b0;
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si->scalefactor[i][1] = b1;
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}
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}
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else {
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for (i = 0; i < SBLIMIT; i++) {
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unsigned char b0 = get_leq_8_bits(mp, 4); /* values 0-15 */
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si->allocation[i][0] = b0;
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if (b0 == ba15)
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illegal_value_detected = 1;
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}
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for (i = 0; i < SBLIMIT; i++) {
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unsigned char n0 = si->allocation[i][0];
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unsigned char b0 = n0 ? get_leq_8_bits(mp, 6) : 0; /* values 0-63 */
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si->scalefactor[i][0] = b0;
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}
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}
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return illegal_value_detected;
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}
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static void
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I_step_two(PMPSTR mp, sideinfo_layer_I *si, real fraction[2][SBLIMIT])
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{
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double r0, r1;
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struct frame *fr = &(mp->fr);
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int ds_limit = fr->down_sample_sblimit;
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int i;
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assert(fr->stereo == 1 || fr->stereo == 2);
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if (fr->stereo == 2) {
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int jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext << 2) + 4 : 32;
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for (i = 0; i < jsbound; i++) {
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unsigned char i0 = si->scalefactor[i][0];
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unsigned char i1 = si->scalefactor[i][1];
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unsigned char n0 = si->allocation[i][0];
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unsigned char n1 = si->allocation[i][1];
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assert( i0 < 64 );
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assert( i1 < 64 );
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assert( n0 < 16 );
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assert( n1 < 16 );
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if (n0 > 0) {
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unsigned short v = get_leq_16_bits(mp, n0 + 1); /* 0-65535 */
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r0 = (((-1) << n0) + v + 1) * muls[n0 + 1][i0];
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}
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else {
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r0 = 0;
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}
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if (n1 > 0) {
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unsigned short v = get_leq_16_bits(mp, n1 + 1); /* 0-65535 */
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r1 = (((-1) << n1) + v + 1) * muls[n1 + 1][i1];
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}
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else {
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r1 = 0;
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}
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fraction[0][i] = (real)r0;
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fraction[1][i] = (real)r1;
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}
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for (i = jsbound; i < SBLIMIT; i++) {
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unsigned char i0 = si->scalefactor[i][0];
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unsigned char i1 = si->scalefactor[i][1];
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unsigned char n = si->allocation[i][0];
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assert( i0 < 64 );
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assert( i1 < 64 );
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assert( n < 16 );
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if (n > 0) {
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unsigned short v = get_leq_16_bits(mp, n + 1); /* 0-65535 */
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unsigned int w = (((-1) << n) + v + 1);
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r0 = w * muls[n + 1][i0];
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r1 = w * muls[n + 1][i1];
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}
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else {
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r0 = r1 = 0;
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}
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fraction[0][i] = (real)r0;
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fraction[1][i] = (real)r1;
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}
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for (i = ds_limit; i < SBLIMIT; i++) {
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fraction[0][i] = 0.0;
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fraction[1][i] = 0.0;
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}
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}
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else {
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for (i = 0; i < SBLIMIT; i++) {
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unsigned char n = si->allocation[i][0];
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unsigned char j = si->scalefactor[i][0];
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assert( j < 64 );
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assert( n < 16 );
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if (n > 0) {
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unsigned short v = get_leq_16_bits(mp, n + 1);
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r0 = (((-1) << n) + v + 1) * muls[n + 1][j];
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}
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else {
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r0 = 0;
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}
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fraction[0][i] = (real)r0;
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}
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for (i = ds_limit; i < SBLIMIT; i++) {
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fraction[0][i] = 0.0;
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}
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}
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}
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int
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decode_layer1_sideinfo(PMPSTR mp)
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{
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(void) mp;
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/* FIXME: extract side information and check values */
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return 0;
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}
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int
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decode_layer1_frame(PMPSTR mp, unsigned char *pcm_sample, int *pcm_point)
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{
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real fraction[2][SBLIMIT]; /* FIXME: change real -> double ? */
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sideinfo_layer_I si;
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struct frame *fr = &(mp->fr);
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int single = fr->single;
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int i, clip = 0;
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if (I_step_one(mp, &si)) {
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lame_report_fnc(mp->report_err, "hip: Aborting layer 1 decode, illegal bit allocation value\n");
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return -1;
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}
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if (fr->stereo == 1 || single == 3)
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single = 0;
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if (single >= 0) {
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/* decoding one of possibly two channels */
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for (i = 0; i < SCALE_BLOCK; i++) {
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I_step_two(mp, &si, fraction);
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clip += synth_1to1_mono(mp, (real *) fraction[single], pcm_sample, pcm_point);
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}
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}
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else {
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for (i = 0; i < SCALE_BLOCK; i++) {
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int p1 = *pcm_point;
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I_step_two(mp, &si, fraction);
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clip += synth_1to1(mp, (real *) fraction[0], 0, pcm_sample, &p1);
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clip += synth_1to1(mp, (real *) fraction[1], 1, pcm_sample, pcm_point);
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}
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}
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return clip;
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}
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