forked from KolibriOS/kolibrios
206 lines
6.4 KiB
C
206 lines
6.4 KiB
C
#include "bstream.h"
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#include "mp3dec.h"
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#include <math.h>
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extern MPEG_DECODE_OPTION m_option;
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extern int m_frequency;
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extern float m_sample[2304];
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extern int m_nsb_limit;
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extern int m_max_sb;
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extern SBT_PROC m_sbt_proc;
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extern float m_sf_table[64];
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extern float m_look_c_valueL2[18];
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extern char m_group3_table[32][3];
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extern char m_group5_table[128][3];
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extern short m_group9_table[1024][3];
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extern int m_nbat[4];// = {3, 8, 12, 7};
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extern int m_bat[4][16];
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/* ABCD_INDEX = lookqt[mode][sr_index][br_index] */
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/* -1 = invalid */
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static const char lookqt[4][3][16] =
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{
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1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks stereo */
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0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
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1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
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1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks joint stereo */
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0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
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1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
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1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks dual chan */
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0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
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1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
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// mono extended beyond legal br index
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// 1,2,2,0,0,0,1,1,1,1,1,1,1,1,1,-1, /* 44ks single chan */
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// 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,-1, /* 48ks */
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// 1,3,3,0,0,0,1,1,1,1,1,1,1,1,1,-1, /* 32ks */
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// legal mono
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1, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, /* 44ks single chan */
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0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, /* 48ks */
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1, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, /* 32ks */
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};
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/* bit allocation table look up */
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/* table per mpeg spec tables 3b2a/b/c/d /e is mpeg2 */
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/* look_bat[abcd_index][4][16] */
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static const unsigned char look_bat[5][4][16] =
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{
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/* LOOK_BATA */
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0, 1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17,
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0, 1, 2, 3, 4, 5, 6, 17, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 17, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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/* LOOK_BATB */
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0, 1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17,
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0, 1, 2, 3, 4, 5, 6, 17, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 17, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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/* LOOK_BATC */
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0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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/* LOOK_BATD */
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0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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/* LOOK_BATE */
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 1, 2, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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};
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/* look_nbat[abcd_index]][4] */
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static const unsigned char look_nbat[5][4] =
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{
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3, 8, 12, 4,
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3, 8, 12, 7,
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2, 0, 6, 0,
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2, 0, 10, 0,
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4, 0, 7, 19,
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};
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//extern "sbt.c"
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void sbt_mono(float *sample, signed short *pcm, int ch);
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void sbt_dual(float *sample, signed short *pcm, int ch);
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void sbt16_mono(float *sample, signed short *pcm, int ch);
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void sbt16_dual(float *sample, signed short *pcm, int ch);
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void sbt8_mono(float *sample, signed short *pcm, int ch);
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void sbt8_dual(float *sample, signed short *pcm, int ch);
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void sbtB_mono(float *sample, unsigned char *pcm, int ch);
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void sbtB_dual(float *sample, unsigned char *pcm, int ch);
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void sbtB16_mono(float *sample, unsigned char *pcm, int ch);
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void sbtB16_dual(float *sample, unsigned char *pcm, int ch);
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void sbtB8_mono(float *sample, unsigned char *pcm, int ch);
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void sbtB8_dual(float *sample, unsigned char *pcm, int ch);
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static const SBT_PROC sbt_table[2][3][2] =
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{
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sbt_mono,
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sbt_dual,
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sbt16_mono,
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sbt16_dual,
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sbt8_mono,
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sbt8_dual,
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sbtB_mono,
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sbtB_dual,
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sbtB16_mono,
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sbtB16_dual,
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sbtB8_mono,
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sbtB8_dual,
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};
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void L2table_init()
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{
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int i, j, code;
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long stepL2[18] = {
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0, 3, 5, 7, 9, 15, 31, 63, 127,
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255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535
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};
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//c_values (dequant)
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for (i = 1; i < 18; i++) {
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m_look_c_valueL2[i] = 2.0F / stepL2[i];
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}
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//scale factor table, scale by 32768 for 16 pcm output
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for (i = 0; i < 64; i++) {
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m_sf_table[i] = (float) (32768.0 * 2.0 * pow_test(2.0, -i / 3.0));
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}
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//grouped 3 level lookup table 5 bit token
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for (i = 0; i < 32; i++) {
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code = i;
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for (j = 0; j < 3; j++) {
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m_group3_table[i][j] = (char) ((code % 3) - 1);
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code /= 3;
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}
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}
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//grouped 5 level lookup table 7 bit token
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for (i = 0; i < 128; i++) {
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code = i;
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for (j = 0; j < 3; j++) {
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m_group5_table[i][j] = (char) ((code % 5) - 2);
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code /= 5;
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}
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}
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//grouped 9 level lookup table 10 bit token
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for (i = 0; i < 1024; i++) {
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code = i;
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for (j = 0; j < 3; j++) {
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m_group9_table[i][j] = (short) ((code % 9) - 4);
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code /= 9;
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}
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}
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}
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int L2decode_start(MPEG_HEADER* h)
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{
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int i, j, k, bit_code, limit;
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int abcd_index;
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// compute abcd index for bit allo table selection
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if (h->version == 1) // MPEG-1
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abcd_index = lookqt[h->mode][h->fr_index][h->br_index];
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else
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abcd_index = 4; // MPEG-2, MPEG-2.5
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if (abcd_index < 0)
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return 0; // fail invalid Layer II bit rate index
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for (i = 0; i < 4; i++) {
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m_nbat[i] = look_nbat[abcd_index][i];
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for (j = 0; j < 16; j++) {
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m_bat[i][j] = look_bat[abcd_index][i][j];
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}
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}
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m_max_sb = m_nbat[0] + m_nbat[1] + m_nbat[2] + m_nbat[3];
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// compute nsb_limit
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m_nsb_limit = (m_option.freqLimit * 64L + m_frequency / 2) / m_frequency;
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// caller limit
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// limit = 0.94*(32>>reduction_code);
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limit = (32 >> m_option.reduction);
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if (limit > 8)
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limit--;
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if (m_nsb_limit > limit)
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m_nsb_limit = limit;
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if (m_nsb_limit > m_max_sb)
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m_nsb_limit = m_max_sb;
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if (h->mode != 3) {
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// adjust for 2 channel modes
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for (i = 0; i < 4; i++)
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m_nbat[i] *= 2;
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m_max_sb *= 2;
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m_nsb_limit *= 2;
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}
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// set sbt function
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bit_code = (m_option.convert & 8) ? 1 : 0;
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k = (h->mode == 3) ? 0 : (1 + m_option.convert);
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m_sbt_proc = sbt_table[bit_code][m_option.reduction][k];//[2][3][2]
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// clear sample buffer, unused sub bands must be 0
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for (i = 0; i < 2304; i++)
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m_sample[i] = 0.0F;
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return 1;
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}
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