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FFmpeg/libavcodec/mpc8.c

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  1. /*

  2.  * Musepack SV8 decoder

  3.  * Copyright (c) 2007 Konstantin Shishkov

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * FFmpeg is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with FFmpeg; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file mpc8.c Musepack SV8 decoder

  24.  * MPEG Audio Layer 1/2 -like codec with frames of 1152 samples

  25.  * divided into 32 subbands.

  26.  */

  27. 

  28. #include "libavutil/random.h"

  29. #include "avcodec.h"

  30. #include "bitstream.h"

  31. #include "dsputil.h"

  32. 

  33. #ifdef CONFIG_MPEGAUDIO_HP

  34. #define USE_HIGHPRECISION

  35. #endif

  36. #include "mpegaudio.h"

  37. 

  38. #include "mpc.h"

  39. #include "mpcdata.h"

  40. #include "mpc8data.h"

  41. #include "mpc8huff.h"

  42. 

  43. static VLC band_vlc, scfi_vlc[2], dscf_vlc[2], res_vlc[2];

  44. static VLC q1_vlc, q2_vlc[2], q3_vlc[2], quant_vlc[4][2], q9up_vlc;

  45. 

  46. static const int q3_offsets[2] = { MPC8_Q3_OFFSET, MPC8_Q4_OFFSET };

  47. static const int quant_offsets[6] = { MPC8_Q5_OFFSET, MPC8_Q6_OFFSET, MPC8_Q7_OFFSET, MPC8_Q8_OFFSET };

  48. 

  49. static inline int mpc8_dec_base(GetBitContext *gb, int k, int n)

  50. {

  51.     int code = get_bits(gb, mpc8_cnk_len[k-1][n-1] - 1);

  52. 

  53.     if (code >= mpc8_cnk_lost[k-1][n-1])

  54.         code = ((code << 1) | get_bits1(gb)) - mpc8_cnk_lost[k-1][n-1];

  55. 

  56.     return code;

  57. }

  58. 

  59. static inline int mpc8_dec_enum(GetBitContext *gb, int k, int n)

  60. {

  61.     int bits = 0;

  62.     const uint32_t * C = mpc8_cnk[k-1];

  63.     int code = mpc8_dec_base(gb, k, n);

  64. 

  65.     do {

  66.         n--;

  67.         if (code >= C[n]) {

  68.             bits |= 1 << n;

  69.             code -= C[n];

  70.             C -= 32;

  71.             k--;

  72.         }

  73.     } while(k > 0);

  74. 

  75.     return bits;

  76. }

  77. 

  78. static inline int mpc8_get_mod_golomb(GetBitContext *gb, int m)

  79. {

  80.     if(mpc8_cnk_len[0][m] < 1) return 0;

  81.     return mpc8_dec_base(gb, 1, m+1);

  82. }

  83. 

  84. static int mpc8_get_mask(GetBitContext *gb, int size, int t)

  85. {

  86.     int mask = 0;

  87. 

  88.     if(t && t != size)

  89.          mask = mpc8_dec_enum(gb, FFMIN(t, size - t), size);

  90.     if((t << 1) > size) mask = ~mask;

  91. 

  92.     return mask;

  93. }

  94. 

  95. static av_cold int mpc8_decode_init(AVCodecContext * avctx)

  96. {

  97.     int i;

  98.     MPCContext *c = avctx->priv_data;

  99.     GetBitContext gb;

  100.     static int vlc_initialized = 0;

  101. 

  102.     if(avctx->extradata_size < 2){

  103.         av_log(avctx, AV_LOG_ERROR, "Too small extradata size (%i)!\n", avctx->extradata_size);

  104.         return -1;

  105.     }

  106.     memset(c->oldDSCF, 0, sizeof(c->oldDSCF));

  107.     av_init_random(0xDEADBEEF, &c->rnd);

  108.     dsputil_init(&c->dsp, avctx);

  109. 

  110.     ff_mpc_init();

  111. 

  112.     init_get_bits(&gb, avctx->extradata, 16);

  113. 

  114.     skip_bits(&gb, 3);//sample rate

  115.     c->maxbands = get_bits(&gb, 5) + 1;

  116.     skip_bits(&gb, 4);//channels

  117.     c->MSS = get_bits1(&gb);

  118.     c->frames = 1 << (get_bits(&gb, 3) * 2);

  119. 

  120.     if(vlc_initialized) return 0;

  121.     av_log(avctx, AV_LOG_DEBUG, "Initing VLC\n");

  122. 

  123.     init_vlc(&band_vlc, MPC8_BANDS_BITS, MPC8_BANDS_SIZE,

  124.              mpc8_bands_bits,  1, 1,

  125.              mpc8_bands_codes, 1, 1, INIT_VLC_USE_STATIC);

  126. 

  127.     init_vlc(&q1_vlc, MPC8_Q1_BITS, MPC8_Q1_SIZE,

  128.              mpc8_q1_bits,  1, 1,

  129.              mpc8_q1_codes, 1, 1, INIT_VLC_USE_STATIC);

  130.     init_vlc(&q9up_vlc, MPC8_Q9UP_BITS, MPC8_Q9UP_SIZE,

  131.              mpc8_q9up_bits,  1, 1,

  132.              mpc8_q9up_codes, 1, 1, INIT_VLC_USE_STATIC);

  133. 

  134.     init_vlc(&scfi_vlc[0], MPC8_SCFI0_BITS, MPC8_SCFI0_SIZE,

  135.              mpc8_scfi0_bits,  1, 1,

  136.              mpc8_scfi0_codes, 1, 1, INIT_VLC_USE_STATIC);

  137.     init_vlc(&scfi_vlc[1], MPC8_SCFI1_BITS, MPC8_SCFI1_SIZE,

  138.              mpc8_scfi1_bits,  1, 1,

  139.              mpc8_scfi1_codes, 1, 1, INIT_VLC_USE_STATIC);

  140. 

  141.     init_vlc(&dscf_vlc[0], MPC8_DSCF0_BITS, MPC8_DSCF0_SIZE,

  142.              mpc8_dscf0_bits,  1, 1,

  143.              mpc8_dscf0_codes, 1, 1, INIT_VLC_USE_STATIC);

  144.     init_vlc(&dscf_vlc[1], MPC8_DSCF1_BITS, MPC8_DSCF1_SIZE,

  145.              mpc8_dscf1_bits,  1, 1,

  146.              mpc8_dscf1_codes, 1, 1, INIT_VLC_USE_STATIC);

  147. 

  148.     init_vlc_sparse(&q3_vlc[0], MPC8_Q3_BITS, MPC8_Q3_SIZE,

  149.              mpc8_q3_bits,  1, 1,

  150.              mpc8_q3_codes, 1, 1,

  151.              mpc8_q3_syms,  1, 1, INIT_VLC_USE_STATIC);

  152.     init_vlc_sparse(&q3_vlc[1], MPC8_Q4_BITS, MPC8_Q4_SIZE,

  153.              mpc8_q4_bits,  1, 1,

  154.              mpc8_q4_codes, 1, 1,

  155.              mpc8_q4_syms,  1, 1, INIT_VLC_USE_STATIC);

  156. 

  157.     for(i = 0; i < 2; i++){

  158.         init_vlc(&res_vlc[i], MPC8_RES_BITS, MPC8_RES_SIZE,

  159.                  &mpc8_res_bits[i],  1, 1,

  160.                  &mpc8_res_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  161. 

  162.         init_vlc(&q2_vlc[i], MPC8_Q2_BITS, MPC8_Q2_SIZE,

  163.                  &mpc8_q2_bits[i],  1, 1,

  164.                  &mpc8_q2_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  165. 

  166.         init_vlc(&quant_vlc[0][i], MPC8_Q5_BITS, MPC8_Q5_SIZE,

  167.                  &mpc8_q5_bits[i],  1, 1,

  168.                  &mpc8_q5_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  169.         init_vlc(&quant_vlc[1][i], MPC8_Q6_BITS, MPC8_Q6_SIZE,

  170.                  &mpc8_q6_bits[i],  1, 1,

  171.                  &mpc8_q6_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  172.         init_vlc(&quant_vlc[2][i], MPC8_Q7_BITS, MPC8_Q7_SIZE,

  173.                  &mpc8_q7_bits[i],  1, 1,

  174.                  &mpc8_q7_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  175.         init_vlc(&quant_vlc[3][i], MPC8_Q8_BITS, MPC8_Q8_SIZE,

  176.                  &mpc8_q8_bits[i],  1, 1,

  177.                  &mpc8_q8_codes[i], 1, 1, INIT_VLC_USE_STATIC);

  178.     }

  179.     vlc_initialized = 1;

  180.     avctx->sample_fmt = SAMPLE_FMT_S16;

  181.     avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;

  182.     return 0;

  183. }

  184. 

  185. static int mpc8_decode_frame(AVCodecContext * avctx,

  186.                             void *data, int *data_size,

  187.                             const uint8_t * buf, int buf_size)

  188. {

  189.     MPCContext *c = avctx->priv_data;

  190.     GetBitContext gb2, *gb = &gb2;

  191.     int i, j, k, ch, cnt, res, t;

  192.     Band *bands = c->bands;

  193.     int off;

  194.     int maxband, keyframe;

  195.     int last[2];

  196. 

  197.     keyframe = c->cur_frame == 0;

  198. 

  199.     if(keyframe){

  200.         memset(c->Q, 0, sizeof(c->Q));

  201.         c->last_bits_used = 0;

  202.     }

  203.     init_get_bits(gb, buf, buf_size * 8);

  204.     skip_bits(gb, c->last_bits_used & 7);

  205. 

  206.     if(keyframe)

  207.         maxband = mpc8_get_mod_golomb(gb, c->maxbands + 1);

  208.     else{

  209.         maxband = c->last_max_band + get_vlc2(gb, band_vlc.table, MPC8_BANDS_BITS, 2);

  210.         if(maxband > 32) maxband -= 33;

  211.     }

  212.     c->last_max_band = maxband;

  213. 

  214.     /* read subband indexes */

  215.     if(maxband){

  216.         last[0] = last[1] = 0;

  217.         for(i = maxband - 1; i >= 0; i--){

  218.             for(ch = 0; ch < 2; ch++){

  219.                 last[ch] = get_vlc2(gb, res_vlc[last[ch] > 2].table, MPC8_RES_BITS, 2) + last[ch];

  220.                 if(last[ch] > 15) last[ch] -= 17;

  221.                 bands[i].res[ch] = last[ch];

  222.             }

  223.         }

  224.         if(c->MSS){

  225.             int mask;

  226. 

  227.             cnt = 0;

  228.             for(i = 0; i < maxband; i++)

  229.                 if(bands[i].res[0] || bands[i].res[1])

  230.                     cnt++;

  231.             t = mpc8_get_mod_golomb(gb, cnt);

  232.             mask = mpc8_get_mask(gb, cnt, t);

  233.             for(i = maxband - 1; i >= 0; i--)

  234.                 if(bands[i].res[0] || bands[i].res[1]){

  235.                     bands[i].msf = mask & 1;

  236.                     mask >>= 1;

  237.                 }

  238.         }

  239.     }

  240.     for(i = maxband; i < c->maxbands; i++)

  241.         bands[i].res[0] = bands[i].res[1] = 0;

  242. 

  243.     if(keyframe){

  244.         for(i = 0; i < 32; i++)

  245.             c->oldDSCF[0][i] = c->oldDSCF[1][i] = 1;

  246.     }

  247. 

  248.     for(i = 0; i < maxband; i++){

  249.         if(bands[i].res[0] || bands[i].res[1]){

  250.             cnt = !!bands[i].res[0] + !!bands[i].res[1] - 1;

  251.             if(cnt >= 0){

  252.                 t = get_vlc2(gb, scfi_vlc[cnt].table, scfi_vlc[cnt].bits, 1);

  253.                 if(bands[i].res[0]) bands[i].scfi[0] = t >> (2 * cnt);

  254.                 if(bands[i].res[1]) bands[i].scfi[1] = t & 3;

  255.             }

  256.         }

  257.     }

  258. 

  259.     for(i = 0; i < maxband; i++){

  260.         for(ch = 0; ch < 2; ch++){

  261.             if(!bands[i].res[ch]) continue;

  262. 

  263.             if(c->oldDSCF[ch][i]){

  264.                 bands[i].scf_idx[ch][0] = get_bits(gb, 7) - 6;

  265.                 c->oldDSCF[ch][i] = 0;

  266.             }else{

  267.                 t = get_vlc2(gb, dscf_vlc[1].table, MPC8_DSCF1_BITS, 2);

  268.                 if(t == 64)

  269.                     t += get_bits(gb, 6);

  270.                 bands[i].scf_idx[ch][0] = ((bands[i].scf_idx[ch][2] + t - 25) & 0x7F) - 6;

  271.             }

  272.             for(j = 0; j < 2; j++){

  273.                 if((bands[i].scfi[ch] << j) & 2)

  274.                     bands[i].scf_idx[ch][j + 1] = bands[i].scf_idx[ch][j];

  275.                 else{

  276.                     t = get_vlc2(gb, dscf_vlc[0].table, MPC8_DSCF0_BITS, 2);

  277.                     if(t == 31)

  278.                         t = 64 + get_bits(gb, 6);

  279.                     bands[i].scf_idx[ch][j + 1] = ((bands[i].scf_idx[ch][j] + t - 25) & 0x7F) - 6;

  280.                 }

  281.             }

  282.         }

  283.     }

  284. 

  285.     for(i = 0, off = 0; i < maxband; i++, off += SAMPLES_PER_BAND){

  286.         for(ch = 0; ch < 2; ch++){

  287.             res = bands[i].res[ch];

  288.             switch(res){

  289.             case -1:

  290.                 for(j = 0; j < SAMPLES_PER_BAND; j++)

  291.                     c->Q[ch][off + j] = (av_random(&c->rnd) & 0x3FC) - 510;

  292.                 break;

  293.             case 0:

  294.                 break;

  295.             case 1:

  296.                 for(j = 0; j < SAMPLES_PER_BAND; j += SAMPLES_PER_BAND / 2){

  297.                     cnt = get_vlc2(gb, q1_vlc.table, MPC8_Q1_BITS, 2);

  298.                     t = mpc8_get_mask(gb, 18, cnt);

  299.                     for(k = 0; k < SAMPLES_PER_BAND / 2; k++, t <<= 1)

  300.                         c->Q[ch][off + j + k] = (t & 0x20000) ? (get_bits1(gb) << 1) - 1 : 0;

  301.                 }

  302.                 break;

  303.             case 2:

  304.                 cnt = 6;//2*mpc8_thres[res]

  305.                 for(j = 0; j < SAMPLES_PER_BAND; j += 3){

  306.                     t = get_vlc2(gb, q2_vlc[cnt > 3].table, MPC8_Q2_BITS, 2);

  307.                     c->Q[ch][off + j + 0] = mpc8_idx50[t];

  308.                     c->Q[ch][off + j + 1] = mpc8_idx51[t];

  309.                     c->Q[ch][off + j + 2] = mpc8_idx52[t];

  310.                     cnt = (cnt >> 1) + mpc8_huffq2[t];

  311.                 }

  312.                 break;

  313.             case 3:

  314.             case 4:

  315.                 for(j = 0; j < SAMPLES_PER_BAND; j += 2){

  316.                     t = get_vlc2(gb, q3_vlc[res - 3].table, MPC8_Q3_BITS, 2) + q3_offsets[res - 3];

  317.                     c->Q[ch][off + j + 1] = t >> 4;

  318.                     c->Q[ch][off + j + 0] = (t & 8) ? (t & 0xF) - 16 : (t & 0xF);

  319.                 }

  320.                 break;

  321.             case 5:

  322.             case 6:

  323.             case 7:

  324.             case 8:

  325.                 cnt = 2 * mpc8_thres[res];

  326.                 for(j = 0; j < SAMPLES_PER_BAND; j++){

  327.                     t = get_vlc2(gb, quant_vlc[res - 5][cnt > mpc8_thres[res]].table, quant_vlc[res - 5][cnt > mpc8_thres[res]].bits, 2) + quant_offsets[res - 5];

  328.                     c->Q[ch][off + j] = t;

  329.                     cnt = (cnt >> 1) + FFABS(c->Q[ch][off + j]);

  330.                 }

  331.                 break;

  332.             default:

  333.                 for(j = 0; j < SAMPLES_PER_BAND; j++){

  334.                     c->Q[ch][off + j] = get_vlc2(gb, q9up_vlc.table, MPC8_Q9UP_BITS, 2);

  335.                     if(res != 9){

  336.                         c->Q[ch][off + j] <<= res - 9;

  337.                         c->Q[ch][off + j] |= get_bits(gb, res - 9);

  338.                     }

  339.                     c->Q[ch][off + j] -= (1 << (res - 2)) - 1;

  340.                 }

  341.             }

  342.         }

  343.     }

  344. 

  345.     ff_mpc_dequantize_and_synth(c, maxband, data);

  346. 

  347.     c->cur_frame++;

  348. 

  349.     c->last_bits_used = get_bits_count(gb);

  350.     if(c->cur_frame >= c->frames)

  351.         c->cur_frame = 0;

  352.     *data_size =  MPC_FRAME_SIZE * 4;

  353. 

  354.     return c->cur_frame ? c->last_bits_used >> 3 : buf_size;

  355. }

  356. 

  357. AVCodec mpc8_decoder = {

  358.     "mpc8",

  359.     CODEC_TYPE_AUDIO,

  360.     CODEC_ID_MUSEPACK8,

  361.     sizeof(MPCContext),

  362.     mpc8_decode_init,

  363.     NULL,

  364.     NULL,

  365.     mpc8_decode_frame,

  366.     .long_name = NULL_IF_CONFIG_SMALL("Musepack SV8"),

  367. };