mp3tabs.c

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/**************************************************************************************
 * Fixed-point MP3 decoder
 * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 * June 2003
 *
 * mp3tabs.c - platform-independent tables for MP3 decoder (global, read-only)
 **************************************************************************************/
 
#include "mp3common.h"
 
/* indexing = [version][samplerate index]
 * sample rate of frame (Hz)
 */
const int samplerateTab[3][3] = {
  {44100, 48000, 32000},    /* MPEG-1 */
  {22050, 24000, 16000},    /* MPEG-2 */
  {11025, 12000,  8000},    /* MPEG-2.5 */
};
 
/* indexing = [version][layer][bitrate index]
 * bitrate (kbps) of frame
 *   - bitrate index == 0 is "free" mode (bitrate determined on the fly by
 *       counting bits between successive sync words)
 */
const short bitrateTab[3][3][15] = {
  {
    /* MPEG-1 */
    {  0, 32, 64, 96,128,160,192,224,256,288,320,352,384,416,448}, /* Layer 1 */
    {  0, 32, 48, 56, 64, 80, 96,112,128,160,192,224,256,320,384}, /* Layer 2 */
    {  0, 32, 40, 48, 56, 64, 80, 96,112,128,160,192,224,256,320}, /* Layer 3 */
  },
  {
    /* MPEG-2 */
    {  0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256}, /* Layer 1 */
    {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}, /* Layer 2 */
    {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}, /* Layer 3 */
  },
  {
    /* MPEG-2.5 */
    {  0, 32, 48, 56, 64, 80, 96,112,128,144,160,176,192,224,256}, /* Layer 1 */
    {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}, /* Layer 2 */
    {  0,  8, 16, 24, 32, 40, 48, 56, 64, 80, 96,112,128,144,160}, /* Layer 3 */
  },
};
 
/* indexing = [version][layer]
 * number of samples in one frame (per channel)
 */
const short samplesPerFrameTab[3][3] = {
  {384, 1152, 1152 }, /* MPEG1 */
  {384, 1152,  576 }, /* MPEG2 */
  {384, 1152,  576 }, /* MPEG2.5 */
};
 
/* layers 1, 2, 3 */
const short bitsPerSlotTab[3] = {32, 8, 8};
 
/* indexing = [version][mono/stereo]
 * number of bytes in side info section of bitstream 
 */
const short sideBytesTab[3][2] = {
  {17, 32}, /* MPEG-1:   mono, stereo */
  { 9, 17}, /* MPEG-2:   mono, stereo */
  { 9, 17}, /* MPEG-2.5: mono, stereo */
};
 
/* indexing = [version][sampleRate][bitRate] 
 * for layer3, nSlots = floor(samps/frame * bitRate / sampleRate / 8)
 *   - add one pad slot if necessary
 */
const short slotTab[3][3][15] = {
  {
    /* MPEG-1 */
    { 0, 104, 130, 156, 182, 208, 261, 313, 365, 417, 522, 626, 731, 835,1044 },  /* 44 kHz */
    { 0,  96, 120, 144, 168, 192, 240, 288, 336, 384, 480, 576, 672, 768, 960 },  /* 48 kHz */
    { 0, 144, 180, 216, 252, 288, 360, 432, 504, 576, 720, 864,1008,1152,1440 },  /* 32 kHz */
  },
  { 
    /* MPEG-2 */
    { 0,  26,  52,  78, 104, 130, 156, 182, 208, 261, 313, 365, 417, 470, 522 },  /* 22 kHz */
    { 0,  24,  48,  72,  96, 120, 144, 168, 192, 240, 288, 336, 384, 432, 480 },  /* 24 kHz */
    { 0,  36,  72, 108, 144, 180, 216, 252, 288, 360, 432, 504, 576, 648, 720 },  /* 16 kHz */
  },
  {
    /* MPEG-2.5 */
    { 0,  52, 104, 156, 208, 261, 313, 365, 417, 522, 626, 731, 835, 940,1044 },  /* 11 kHz */
    { 0,  48,  96, 144, 192, 240, 288, 336, 384, 480, 576, 672, 768, 864, 960 },  /* 12 kHz */
    { 0,  72, 144, 216, 288, 360, 432, 504, 576, 720, 864,1008,1152,1296,1440 },  /*  8 kHz */
  },
};
 
/* indexing = [version][sampleRate][long (.l) or short (.s) block] 
 *   sfBandTable[v][s].l[cb] = index of first bin in critical band cb (long blocks)
 *   sfBandTable[v][s].s[cb] = index of first bin in critical band cb (short blocks)
 */
const SFBandTable sfBandTable[3][3] = {
  {
    /* MPEG-1 (44, 48, 32 kHz) */
    {
      { 0,  4,  8, 12, 16, 20, 24, 30, 36, 44, 52, 62, 74, 90,110,134,162,196,238,288,342,418,576 },
      { 0,  4,  8, 12, 16, 22, 30, 40, 52, 66, 84,106,136,192 }
    },
    {
      { 0,  4,  8, 12, 16, 20, 24, 30, 36, 42, 50, 60, 72, 88,106,128,156,190,230,276,330,384,576 },
      { 0,  4,  8, 12, 16, 22, 28, 38, 50, 64, 80,100,126,192 }
    },
    {
      { 0,  4,  8, 12, 16, 20, 24, 30, 36, 44, 54, 66, 82,102,126,156,194,240,296,364,448,550,576 },
      { 0,  4,  8, 12, 16, 22, 30, 42, 58, 78,104,138,180,192 }
    }
  },
 
  {
    /* MPEG-2 (22, 24, 16 kHz) */
    {
      { 0,  6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96,116,140,168,200,238,284,336,396,464,522,576 },
      { 0,  4,  8, 12, 18, 24, 32, 42, 56, 74,100,132,174,192 }
    },
    {
      { 0,  6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96,114,136,162,194,232,278,332,394,464,540,576 },
      { 0,  4,  8, 12, 18, 26, 36, 48, 62, 80,104,136,180,192 }
    },
    {
      { 0,  6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96,116,140,168,200,238,284,336,396,464,522,576 }, 
      { 0,  4,  8, 12, 18, 26, 36, 48, 62, 80,104,134,174,192 }
    },
  },
 
  {
    /* MPEG-2.5 (11, 12, 8 kHz) */
    {
      { 0,  6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96,116,140,168,200,238,284,336,396,464,522,576 },
      { 0,  4,  8, 12, 18, 26, 36, 48, 62, 80,104,134,174,192 }
    },
    {
      { 0,  6, 12, 18, 24, 30, 36, 44, 54, 66, 80, 96,116,140,168,200,238,284,336,396,464,522,576 },
      { 0,  4,  8, 12, 18, 26, 36, 48, 62, 80,104,134,174,192 }
    },
    {
      { 0, 12, 24, 36, 48, 60, 72, 88,108,132,160,192,232,280,336,400,476,566,568,570,572,574,576 },
      { 0,  8, 16, 24, 36, 52, 72, 96,124,160,162,164,166,192 }
    },
  },
};