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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 libavcodec/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. #include "mpegaudio.h"

  33. 

  34. #include "mpc.h"

  35. #include "mpcdata.h"

  36. #include "mpc8data.h"

  37. #include "mpc8huff.h"

  38. 

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

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

  41. 

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

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

  44. 

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

  46. {

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

  48. 

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

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

  51. 

  52.     return code;

  53. }

  54. 

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

  56. {

  57.     int bits = 0;

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

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

  60. 

  61.     do {

  62.         n--;

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

  64.             bits |= 1 << n;

  65.             code -= C[n];

  66.             C -= 32;

  67.             k--;

  68.         }

  69.     } while(k > 0);

  70. 

  71.     return bits;

  72. }

  73. 

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

  75. {

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

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

  78. }

  79. 

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

  81. {

  82.     int mask = 0;

  83. 

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

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

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

  87. 

  88.     return mask;

  89. }

  90. 

  91. static av_cold int mpc8_decode_init(AVCodecContext * avctx)

  92. {

  93.     int i;

  94.     MPCContext *c = avctx->priv_data;

  95.     GetBitContext gb;

  96.     static int vlc_initialized = 0;

  97. 

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

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

  100.         return -1;

  101.     }

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

  103.     av_random_init(&c->rnd, 0xDEADBEEF);

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

  105. 

  106.     ff_mpc_init();

  107. 

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

  109. 

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

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

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

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

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

  115. 

  116.     if(vlc_initialized) return 0;

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

  118. 

  119.     init_vlc(&band_vlc, MPC8_BANDS_BITS, MPC8_BANDS_SIZE,

  120.              mpc8_bands_bits,  1, 1,

  121.              mpc8_bands_codes, 1, 1, INIT_VLC_USE_STATIC);

  122. 

  123.     init_vlc(&q1_vlc, MPC8_Q1_BITS, MPC8_Q1_SIZE,

  124.              mpc8_q1_bits,  1, 1,

  125.              mpc8_q1_codes, 1, 1, INIT_VLC_USE_STATIC);

  126.     init_vlc(&q9up_vlc, MPC8_Q9UP_BITS, MPC8_Q9UP_SIZE,

  127.              mpc8_q9up_bits,  1, 1,

  128.              mpc8_q9up_codes, 1, 1, INIT_VLC_USE_STATIC);

  129. 

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

  131.              mpc8_scfi0_bits,  1, 1,

  132.              mpc8_scfi0_codes, 1, 1, INIT_VLC_USE_STATIC);

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

  134.              mpc8_scfi1_bits,  1, 1,

  135.              mpc8_scfi1_codes, 1, 1, INIT_VLC_USE_STATIC);

  136. 

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

  138.              mpc8_dscf0_bits,  1, 1,

  139.              mpc8_dscf0_codes, 1, 1, INIT_VLC_USE_STATIC);

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

  141.              mpc8_dscf1_bits,  1, 1,

  142.              mpc8_dscf1_codes, 1, 1, INIT_VLC_USE_STATIC);

  143. 

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

  145.              mpc8_q3_bits,  1, 1,

  146.              mpc8_q3_codes, 1, 1,

  147.              mpc8_q3_syms,  1, 1, INIT_VLC_USE_STATIC);

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

  149.              mpc8_q4_bits,  1, 1,

  150.              mpc8_q4_codes, 1, 1,

  151.              mpc8_q4_syms,  1, 1, INIT_VLC_USE_STATIC);

  152. 

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

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

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

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

  157. 

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

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

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

  161. 

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

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

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

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

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

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

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

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

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

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

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

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

  174.     }

  175.     vlc_initialized = 1;

  176.     avctx->sample_fmt = SAMPLE_FMT_S16;

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

  178.     return 0;

  179. }

  180. 

  181. static int mpc8_decode_frame(AVCodecContext * avctx,

  182.                             void *data, int *data_size,

  183.                             const uint8_t * buf, int buf_size)

  184. {

  185.     MPCContext *c = avctx->priv_data;

  186.     GetBitContext gb2, *gb = &gb2;

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

  188.     Band *bands = c->bands;

  189.     int off;

  190.     int maxband, keyframe;

  191.     int last[2];

  192. 

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

  194. 

  195.     if(keyframe){

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

  197.         c->last_bits_used = 0;

  198.     }

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

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

  201. 

  202.     if(keyframe)

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

  204.     else{

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

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

  207.     }

  208.     c->last_max_band = maxband;

  209. 

  210.     /* read subband indexes */

  211.     if(maxband){

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

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

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

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

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

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

  218.             }

  219.         }

  220.         if(c->MSS){

  221.             int mask;

  222. 

  223.             cnt = 0;

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

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

  226.                     cnt++;

  227.             t = mpc8_get_mod_golomb(gb, cnt);

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

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

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

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

  232.                     mask >>= 1;

  233.                 }

  234.         }

  235.     }

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

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

  238. 

  239.     if(keyframe){

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

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

  242.     }

  243. 

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

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

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

  247.             if(cnt >= 0){

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

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

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

  251.             }

  252.         }

  253.     }

  254. 

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

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

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

  258. 

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

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

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

  262.             }else{

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

  264.                 if(t == 64)

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

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

  267.             }

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

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

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

  271.                 else{

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

  273.                     if(t == 31)

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

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

  276.                 }

  277.             }

  278.         }

  279.     }

  280. 

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

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

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

  284.             switch(res){

  285.             case -1:

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

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

  288.                 break;

  289.             case 0:

  290.                 break;

  291.             case 1:

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

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

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

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

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

  297.                 }

  298.                 break;

  299.             case 2:

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

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

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

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

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

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

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

  307.                 }

  308.                 break;

  309.             case 3:

  310.             case 4:

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

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

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

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

  315.                 }

  316.                 break;

  317.             case 5:

  318.             case 6:

  319.             case 7:

  320.             case 8:

  321.                 cnt = 2 * mpc8_thres[res];

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

  323.                     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];

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

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

  326.                 }

  327.                 break;

  328.             default:

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

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

  331.                     if(res != 9){

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

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

  334.                     }

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

  336.                 }

  337.             }

  338.         }

  339.     }

  340. 

  341.     ff_mpc_dequantize_and_synth(c, maxband, data);

  342. 

  343.     c->cur_frame++;

  344. 

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

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

  347.         c->cur_frame = 0;

  348.     *data_size =  MPC_FRAME_SIZE * 4;

  349. 

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

  351. }

  352. 

  353. AVCodec mpc8_decoder = {

  354.     "mpc8",

  355.     CODEC_TYPE_AUDIO,

  356.     CODEC_ID_MUSEPACK8,

  357.     sizeof(MPCContext),

  358.     mpc8_decode_init,

  359.     NULL,

  360.     NULL,

  361.     mpc8_decode_frame,

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

  363. };