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FFmpeg/libavcodec/wavpack.c

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  1. /*

  2.  * WavPack lossless audio decoder

  3.  * Copyright (c) 2006 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. #define ALT_BITSTREAM_READER_LE

  22. #include "avcodec.h"

  23. #include "get_bits.h"

  24. #include "unary.h"

  25. 

  26. /**

  27.  * @file

  28.  * WavPack lossless audio decoder

  29.  */

  30. 

  31. #define WV_MONO         0x00000004

  32. #define WV_JOINT_STEREO 0x00000010

  33. #define WV_FALSE_STEREO 0x40000000

  34. 

  35. #define WV_HYBRID_MODE    0x00000008

  36. #define WV_HYBRID_SHAPE   0x00000008

  37. #define WV_HYBRID_BITRATE 0x00000200

  38. #define WV_HYBRID_BALANCE 0x00000400

  39. 

  40. #define WV_FLT_SHIFT_ONES 0x01

  41. #define WV_FLT_SHIFT_SAME 0x02

  42. #define WV_FLT_SHIFT_SENT 0x04

  43. #define WV_FLT_ZERO_SENT  0x08

  44. #define WV_FLT_ZERO_SIGN  0x10

  45. 

  46. enum WP_ID_Flags{

  47.     WP_IDF_MASK   = 0x1F,

  48.     WP_IDF_IGNORE = 0x20,

  49.     WP_IDF_ODD    = 0x40,

  50.     WP_IDF_LONG   = 0x80

  51. };

  52. 

  53. enum WP_ID{

  54.     WP_ID_DUMMY = 0,

  55.     WP_ID_ENCINFO,

  56.     WP_ID_DECTERMS,

  57.     WP_ID_DECWEIGHTS,

  58.     WP_ID_DECSAMPLES,

  59.     WP_ID_ENTROPY,

  60.     WP_ID_HYBRID,

  61.     WP_ID_SHAPING,

  62.     WP_ID_FLOATINFO,

  63.     WP_ID_INT32INFO,

  64.     WP_ID_DATA,

  65.     WP_ID_CORR,

  66.     WP_ID_EXTRABITS,

  67.     WP_ID_CHANINFO

  68. };

  69. 

  70. typedef struct SavedContext {

  71.     int offset;

  72.     int size;

  73.     int bits_used;

  74.     uint32_t crc;

  75. } SavedContext;

  76. 

  77. #define MAX_TERMS 16

  78. 

  79. typedef struct Decorr {

  80.     int delta;

  81.     int value;

  82.     int weightA;

  83.     int weightB;

  84.     int samplesA[8];

  85.     int samplesB[8];

  86. } Decorr;

  87. 

  88. typedef struct WvChannel {

  89.     int median[3];

  90.     int slow_level, error_limit;

  91.     int bitrate_acc, bitrate_delta;

  92. } WvChannel;

  93. 

  94. typedef struct WavpackContext {

  95.     AVCodecContext *avctx;

  96.     int frame_flags;

  97.     int stereo, stereo_in;

  98.     int joint;

  99.     uint32_t CRC;

  100.     GetBitContext gb;

  101.     int got_extra_bits;

  102.     uint32_t crc_extra_bits;

  103.     GetBitContext gb_extra_bits;

  104.     int data_size; // in bits

  105.     int samples;

  106.     int terms;

  107.     Decorr decorr[MAX_TERMS];

  108.     int zero, one, zeroes;

  109.     int extra_bits;

  110.     int and, or, shift;

  111.     int post_shift;

  112.     int hybrid, hybrid_bitrate;

  113.     int float_flag;

  114.     int float_shift;

  115.     int float_max_exp;

  116.     WvChannel ch[2];

  117.     int samples_left;

  118.     int max_samples;

  119.     int pos;

  120.     SavedContext sc, extra_sc;

  121. } WavpackContext;

  122. 

  123. // exponent table copied from WavPack source

  124. static const uint8_t wp_exp2_table [256] = {

  125.     0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x08, 0x09, 0x0a, 0x0b,

  126.     0x0b, 0x0c, 0x0d, 0x0e, 0x0e, 0x0f, 0x10, 0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x16,

  127.     0x17, 0x18, 0x19, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1d, 0x1e, 0x1f, 0x20, 0x20, 0x21, 0x22, 0x23,

  128.     0x24, 0x24, 0x25, 0x26, 0x27, 0x28, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,

  129.     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3a, 0x3b, 0x3c, 0x3d,

  130.     0x3e, 0x3f, 0x40, 0x41, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x48, 0x49, 0x4a, 0x4b,

  131.     0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a,

  132.     0x5b, 0x5c, 0x5d, 0x5e, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,

  133.     0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,

  134.     0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x87, 0x88, 0x89, 0x8a,

  135.     0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b,

  136.     0x9c, 0x9d, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad,

  137.     0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0,

  138.     0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc8, 0xc9, 0xca, 0xcb, 0xcd, 0xce, 0xcf, 0xd0, 0xd2, 0xd3, 0xd4,

  139.     0xd6, 0xd7, 0xd8, 0xd9, 0xdb, 0xdc, 0xdd, 0xde, 0xe0, 0xe1, 0xe2, 0xe4, 0xe5, 0xe6, 0xe8, 0xe9,

  140.     0xea, 0xec, 0xed, 0xee, 0xf0, 0xf1, 0xf2, 0xf4, 0xf5, 0xf6, 0xf8, 0xf9, 0xfa, 0xfc, 0xfd, 0xff

  141. };

  142. 

  143. static const uint8_t wp_log2_table [] = {

  144.     0x00, 0x01, 0x03, 0x04, 0x06, 0x07, 0x09, 0x0a, 0x0b, 0x0d, 0x0e, 0x10, 0x11, 0x12, 0x14, 0x15,

  145.     0x16, 0x18, 0x19, 0x1a, 0x1c, 0x1d, 0x1e, 0x20, 0x21, 0x22, 0x24, 0x25, 0x26, 0x28, 0x29, 0x2a,

  146.     0x2c, 0x2d, 0x2e, 0x2f, 0x31, 0x32, 0x33, 0x34, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e,

  147.     0x3f, 0x41, 0x42, 0x43, 0x44, 0x45, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4d, 0x4e, 0x4f, 0x50, 0x51,

  148.     0x52, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63,

  149.     0x64, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x74, 0x75,

  150.     0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85,

  151.     0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95,

  152.     0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4,

  153.     0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb2,

  154.     0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc0,

  155.     0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcb, 0xcc, 0xcd, 0xce,

  156.     0xcf, 0xd0, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd8, 0xd9, 0xda, 0xdb,

  157.     0xdc, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe4, 0xe5, 0xe6, 0xe7, 0xe7,

  158.     0xe8, 0xe9, 0xea, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xee, 0xef, 0xf0, 0xf1, 0xf1, 0xf2, 0xf3, 0xf4,

  159.     0xf4, 0xf5, 0xf6, 0xf7, 0xf7, 0xf8, 0xf9, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc, 0xfd, 0xfe, 0xff, 0xff

  160. };

  161. 

  162. static av_always_inline int wp_exp2(int16_t val)

  163. {

  164.     int res, neg = 0;

  165. 

  166.     if(val < 0){

  167.         val = -val;

  168.         neg = 1;

  169.     }

  170. 

  171.     res = wp_exp2_table[val & 0xFF] | 0x100;

  172.     val >>= 8;

  173.     res = (val > 9) ? (res << (val - 9)) : (res >> (9 - val));

  174.     return neg ? -res : res;

  175. }

  176. 

  177. static av_always_inline int wp_log2(int32_t val)

  178. {

  179.     int bits;

  180. 

  181.     if(!val)

  182.         return 0;

  183.     if(val == 1)

  184.         return 256;

  185.     val += val >> 9;

  186.     bits = av_log2(val) + 1;

  187.     if(bits < 9)

  188.         return (bits << 8) + wp_log2_table[(val << (9 - bits)) & 0xFF];

  189.     else

  190.         return (bits << 8) + wp_log2_table[(val >> (bits - 9)) & 0xFF];

  191. }

  192. 

  193. #define LEVEL_DECAY(a)  ((a + 0x80) >> 8)

  194. 

  195. // macros for manipulating median values

  196. #define GET_MED(n) ((c->median[n] >> 4) + 1)

  197. #define DEC_MED(n) c->median[n] -= ((c->median[n] + (128>>n) - 2) / (128>>n)) * 2

  198. #define INC_MED(n) c->median[n] += ((c->median[n] + (128>>n)) / (128>>n)) * 5

  199. 

  200. // macros for applying weight

  201. #define UPDATE_WEIGHT_CLIP(weight, delta, samples, in) \

  202.         if(samples && in){ \

  203.             if((samples ^ in) < 0){ \

  204.                 weight -= delta; \

  205.                 if(weight < -1024) weight = -1024; \

  206.             }else{ \

  207.                 weight += delta; \

  208.                 if(weight > 1024) weight = 1024; \

  209.             } \

  210.         }

  211. 

  212. 

  213. static av_always_inline int get_tail(GetBitContext *gb, int k)

  214. {

  215.     int p, e, res;

  216. 

  217.     if(k<1)return 0;

  218.     p = av_log2(k);

  219.     e = (1 << (p + 1)) - k - 1;

  220.     res = p ? get_bits(gb, p) : 0;

  221.     if(res >= e){

  222.         res = (res<<1) - e + get_bits1(gb);

  223.     }

  224.     return res;

  225. }

  226. 

  227. static void update_error_limit(WavpackContext *ctx)

  228. {

  229.     int i, br[2], sl[2];

  230. 

  231.     for(i = 0; i <= ctx->stereo_in; i++){

  232.         ctx->ch[i].bitrate_acc += ctx->ch[i].bitrate_delta;

  233.         br[i] = ctx->ch[i].bitrate_acc >> 16;

  234.         sl[i] = LEVEL_DECAY(ctx->ch[i].slow_level);

  235.     }

  236.     if(ctx->stereo_in && ctx->hybrid_bitrate){

  237.         int balance = (sl[1] - sl[0] + br[1] + 1) >> 1;

  238.         if(balance > br[0]){

  239.             br[1] = br[0] << 1;

  240.             br[0] = 0;

  241.         }else if(-balance > br[0]){

  242.             br[0] <<= 1;

  243.             br[1] = 0;

  244.         }else{

  245.             br[1] = br[0] + balance;

  246.             br[0] = br[0] - balance;

  247.         }

  248.     }

  249.     for(i = 0; i <= ctx->stereo_in; i++){

  250.         if(ctx->hybrid_bitrate){

  251.             if(sl[i] - br[i] > -0x100)

  252.                 ctx->ch[i].error_limit = wp_exp2(sl[i] - br[i] + 0x100);

  253.             else

  254.                 ctx->ch[i].error_limit = 0;

  255.         }else{

  256.             ctx->ch[i].error_limit = wp_exp2(br[i]);

  257.         }

  258.     }

  259. }

  260. 

  261. static int wv_get_value(WavpackContext *ctx, GetBitContext *gb, int channel, int *last)

  262. {

  263.     int t, t2;

  264.     int sign, base, add, ret;

  265.     WvChannel *c = &ctx->ch[channel];

  266. 

  267.     *last = 0;

  268. 

  269.     if((ctx->ch[0].median[0] < 2U) && (ctx->ch[1].median[0] < 2U) && !ctx->zero && !ctx->one){

  270.         if(ctx->zeroes){

  271.             ctx->zeroes--;

  272.             if(ctx->zeroes){

  273.                 c->slow_level -= LEVEL_DECAY(c->slow_level);

  274.                 return 0;

  275.             }

  276.         }else{

  277.             t = get_unary_0_33(gb);

  278.             if(t >= 2) t = get_bits(gb, t - 1) | (1 << (t-1));

  279.             ctx->zeroes = t;

  280.             if(ctx->zeroes){

  281.                 memset(ctx->ch[0].median, 0, sizeof(ctx->ch[0].median));

  282.                 memset(ctx->ch[1].median, 0, sizeof(ctx->ch[1].median));

  283.                 c->slow_level -= LEVEL_DECAY(c->slow_level);

  284.                 return 0;

  285.             }

  286.         }

  287.     }

  288. 

  289.     if(get_bits_count(gb) >= ctx->data_size){

  290.         *last = 1;

  291.         return 0;

  292.     }

  293. 

  294.     if(ctx->zero){

  295.         t = 0;

  296.         ctx->zero = 0;

  297.     }else{

  298.         t = get_unary_0_33(gb);

  299.         if(get_bits_count(gb) >= ctx->data_size){

  300.             *last = 1;

  301.             return 0;

  302.         }

  303.         if(t == 16) {

  304.             t2 = get_unary_0_33(gb);

  305.             if(t2 < 2) t += t2;

  306.             else t += get_bits(gb, t2 - 1) | (1 << (t2 - 1));

  307.         }

  308. 

  309.         if(ctx->one){

  310.             ctx->one = t&1;

  311.             t = (t>>1) + 1;

  312.         }else{

  313.             ctx->one = t&1;

  314.             t >>= 1;

  315.         }

  316.         ctx->zero = !ctx->one;

  317.     }

  318. 

  319.     if(ctx->hybrid && !channel)

  320.         update_error_limit(ctx);

  321. 

  322.     if(!t){

  323.         base = 0;

  324.         add = GET_MED(0) - 1;

  325.         DEC_MED(0);

  326.     }else if(t == 1){

  327.         base = GET_MED(0);

  328.         add = GET_MED(1) - 1;

  329.         INC_MED(0);

  330.         DEC_MED(1);

  331.     }else if(t == 2){

  332.         base = GET_MED(0) + GET_MED(1);

  333.         add = GET_MED(2) - 1;

  334.         INC_MED(0);

  335.         INC_MED(1);

  336.         DEC_MED(2);

  337.     }else{

  338.         base = GET_MED(0) + GET_MED(1) + GET_MED(2) * (t - 2);

  339.         add = GET_MED(2) - 1;

  340.         INC_MED(0);

  341.         INC_MED(1);

  342.         INC_MED(2);

  343.     }

  344.     if(!c->error_limit){

  345.         ret = base + get_tail(gb, add);

  346.     }else{

  347.         int mid = (base*2 + add + 1) >> 1;

  348.         while(add > c->error_limit){

  349.             if(get_bits1(gb)){

  350.                 add -= (mid - base);

  351.                 base = mid;

  352.             }else

  353.                 add = mid - base - 1;

  354.             mid = (base*2 + add + 1) >> 1;

  355.         }

  356.         ret = mid;

  357.     }

  358.     sign = get_bits1(gb);

  359.     if(ctx->hybrid_bitrate)

  360.         c->slow_level += wp_log2(ret) - LEVEL_DECAY(c->slow_level);

  361.     return sign ? ~ret : ret;

  362. }

  363. 

  364. static inline int wv_get_value_integer(WavpackContext *s, uint32_t *crc, int S)

  365. {

  366.     int bit;

  367. 

  368.     if(s->extra_bits){

  369.         S <<= s->extra_bits;

  370. 

  371.         if(s->got_extra_bits){

  372.             S |= get_bits(&s->gb_extra_bits, s->extra_bits);

  373.             *crc = *crc * 9 + (S&0xffff) * 3 + ((unsigned)S>>16);

  374.         }

  375.     }

  376.     bit = (S & s->and) | s->or;

  377.     return (((S + bit) << s->shift) - bit) << s->post_shift;

  378. }

  379. 

  380. static float wv_get_value_float(WavpackContext *s, uint32_t *crc, int S)

  381. {

  382.     union {

  383.         float    f;

  384.         uint32_t u;

  385.     } value;

  386. 

  387.     int sign;

  388.     int exp = s->float_max_exp;

  389. 

  390.     if(s->got_extra_bits){

  391.         const int max_bits = 1 + 23 + 8 + 1;

  392.         const int left_bits = get_bits_left(&s->gb_extra_bits);

  393. 

  394.         if(left_bits + 8 * FF_INPUT_BUFFER_PADDING_SIZE < max_bits)

  395.             return 0.0;

  396.     }

  397. 

  398.     if(S){

  399.         S <<= s->float_shift;

  400.         sign = S < 0;

  401.         if(sign)

  402.             S = -S;

  403.         if(S >= 0x1000000){

  404.             if(s->got_extra_bits && get_bits1(&s->gb_extra_bits)){

  405.                 S = get_bits(&s->gb_extra_bits, 23);

  406.             }else{

  407.                 S = 0;

  408.             }

  409.             exp = 255;

  410.         }else if(exp){

  411.             int shift = 23 - av_log2(S);

  412.             exp = s->float_max_exp;

  413.             if(exp <= shift){

  414.                 shift = --exp;

  415.             }

  416.             exp -= shift;

  417. 

  418.             if(shift){

  419.                 S <<= shift;

  420.                 if((s->float_flag & WV_FLT_SHIFT_ONES) ||

  421.                    (s->got_extra_bits && (s->float_flag & WV_FLT_SHIFT_SAME) && get_bits1(&s->gb_extra_bits)) ){

  422.                     S |= (1 << shift) - 1;

  423.                 } else if(s->got_extra_bits && (s->float_flag & WV_FLT_SHIFT_SENT)){

  424.                     S |= get_bits(&s->gb_extra_bits, shift);

  425.                 }

  426.             }

  427.         }else{

  428.             exp = s->float_max_exp;

  429.         }

  430.         S &= 0x7fffff;

  431.     }else{

  432.         sign = 0;

  433.         exp = 0;

  434.         if(s->got_extra_bits && (s->float_flag & WV_FLT_ZERO_SENT)){

  435.             if(get_bits1(&s->gb_extra_bits)){

  436.                 S = get_bits(&s->gb_extra_bits, 23);

  437.                 if(s->float_max_exp >= 25)

  438.                     exp = get_bits(&s->gb_extra_bits, 8);

  439.                 sign = get_bits1(&s->gb_extra_bits);

  440.             }else{

  441.                 if(s->float_flag & WV_FLT_ZERO_SIGN)

  442.                     sign = get_bits1(&s->gb_extra_bits);

  443.             }

  444.         }

  445.     }

  446. 

  447.     *crc = *crc * 27 + S * 9 + exp * 3 + sign;

  448. 

  449.     value.u = (sign << 31) | (exp << 23) | S;

  450.     return value.f;

  451. }

  452. 

  453. static void wv_reset_saved_context(WavpackContext *s)

  454. {

  455.     s->pos = 0;

  456.     s->sc.crc = s->extra_sc.crc = 0xFFFFFFFF;

  457. }

  458. 

  459. static inline int wv_unpack_stereo(WavpackContext *s, GetBitContext *gb, void *dst, const int type)

  460. {

  461.     int i, j, count = 0;

  462.     int last, t;

  463.     int A, B, L, L2, R, R2;

  464.     int pos = s->pos;

  465.     uint32_t crc = s->sc.crc;

  466.     uint32_t crc_extra_bits = s->extra_sc.crc;

  467.     int16_t *dst16 = dst;

  468.     int32_t *dst32 = dst;

  469.     float   *dstfl = dst;

  470. 

  471.     if(s->samples_left == s->samples)

  472.         s->one = s->zero = s->zeroes = 0;

  473.     do{

  474.         L = wv_get_value(s, gb, 0, &last);

  475.         if(last) break;

  476.         R = wv_get_value(s, gb, 1, &last);

  477.         if(last) break;

  478.         for(i = 0; i < s->terms; i++){

  479.             t = s->decorr[i].value;

  480.             if(t > 0){

  481.                 if(t > 8){

  482.                     if(t & 1){

  483.                         A = 2 * s->decorr[i].samplesA[0] - s->decorr[i].samplesA[1];

  484.                         B = 2 * s->decorr[i].samplesB[0] - s->decorr[i].samplesB[1];

  485.                     }else{

  486.                         A = (3 * s->decorr[i].samplesA[0] - s->decorr[i].samplesA[1]) >> 1;

  487.                         B = (3 * s->decorr[i].samplesB[0] - s->decorr[i].samplesB[1]) >> 1;

  488.                     }

  489.                     s->decorr[i].samplesA[1] = s->decorr[i].samplesA[0];

  490.                     s->decorr[i].samplesB[1] = s->decorr[i].samplesB[0];

  491.                     j = 0;

  492.                 }else{

  493.                     A = s->decorr[i].samplesA[pos];

  494.                     B = s->decorr[i].samplesB[pos];

  495.                     j = (pos + t) & 7;

  496.                 }

  497.                 if(type != SAMPLE_FMT_S16){

  498.                     L2 = L + ((s->decorr[i].weightA * (int64_t)A + 512) >> 10);

  499.                     R2 = R + ((s->decorr[i].weightB * (int64_t)B + 512) >> 10);

  500.                 }else{

  501.                     L2 = L + ((s->decorr[i].weightA * A + 512) >> 10);

  502.                     R2 = R + ((s->decorr[i].weightB * B + 512) >> 10);

  503.                 }

  504.                 if(A && L) s->decorr[i].weightA -= ((((L ^ A) >> 30) & 2) - 1) * s->decorr[i].delta;

  505.                 if(B && R) s->decorr[i].weightB -= ((((R ^ B) >> 30) & 2) - 1) * s->decorr[i].delta;

  506.                 s->decorr[i].samplesA[j] = L = L2;

  507.                 s->decorr[i].samplesB[j] = R = R2;

  508.             }else if(t == -1){

  509.                 if(type != SAMPLE_FMT_S16)

  510.                     L2 = L + ((s->decorr[i].weightA * (int64_t)s->decorr[i].samplesA[0] + 512) >> 10);

  511.                 else

  512.                     L2 = L + ((s->decorr[i].weightA * s->decorr[i].samplesA[0] + 512) >> 10);

  513.                 UPDATE_WEIGHT_CLIP(s->decorr[i].weightA, s->decorr[i].delta, s->decorr[i].samplesA[0], L);

  514.                 L = L2;

  515.                 if(type != SAMPLE_FMT_S16)

  516.                     R2 = R + ((s->decorr[i].weightB * (int64_t)L2 + 512) >> 10);

  517.                 else

  518.                     R2 = R + ((s->decorr[i].weightB * L2 + 512) >> 10);

  519.                 UPDATE_WEIGHT_CLIP(s->decorr[i].weightB, s->decorr[i].delta, L2, R);

  520.                 R = R2;

  521.                 s->decorr[i].samplesA[0] = R;

  522.             }else{

  523.                 if(type != SAMPLE_FMT_S16)

  524.                     R2 = R + ((s->decorr[i].weightB * (int64_t)s->decorr[i].samplesB[0] + 512) >> 10);

  525.                 else

  526.                     R2 = R + ((s->decorr[i].weightB * s->decorr[i].samplesB[0] + 512) >> 10);

  527.                 UPDATE_WEIGHT_CLIP(s->decorr[i].weightB, s->decorr[i].delta, s->decorr[i].samplesB[0], R);

  528.                 R = R2;

  529. 

  530.                 if(t == -3){

  531.                     R2 = s->decorr[i].samplesA[0];

  532.                     s->decorr[i].samplesA[0] = R;

  533.                 }

  534. 

  535.                 if(type != SAMPLE_FMT_S16)

  536.                     L2 = L + ((s->decorr[i].weightA * (int64_t)R2 + 512) >> 10);

  537.                 else

  538.                     L2 = L + ((s->decorr[i].weightA * R2 + 512) >> 10);

  539.                 UPDATE_WEIGHT_CLIP(s->decorr[i].weightA, s->decorr[i].delta, R2, L);

  540.                 L = L2;

  541.                 s->decorr[i].samplesB[0] = L;

  542.             }

  543.         }

  544.         pos = (pos + 1) & 7;

  545.         if(s->joint)

  546.             L += (R -= (L >> 1));

  547.         crc = (crc * 3 + L) * 3 + R;

  548. 

  549.         if(type == SAMPLE_FMT_FLT){

  550.             *dstfl++ = wv_get_value_float(s, &crc_extra_bits, L);

  551.             *dstfl++ = wv_get_value_float(s, &crc_extra_bits, R);

  552.         } else if(type == SAMPLE_FMT_S32){

  553.             *dst32++ = wv_get_value_integer(s, &crc_extra_bits, L);

  554.             *dst32++ = wv_get_value_integer(s, &crc_extra_bits, R);

  555.         } else {

  556.             *dst16++ = wv_get_value_integer(s, &crc_extra_bits, L);

  557.             *dst16++ = wv_get_value_integer(s, &crc_extra_bits, R);

  558.         }

  559.         count++;

  560.     }while(!last && count < s->max_samples);

  561. 

  562.     s->samples_left -= count;

  563.     if(!s->samples_left){

  564.         if(crc != s->CRC){

  565.             av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");

  566.             return -1;

  567.         }

  568.         if(s->got_extra_bits && crc_extra_bits != s->crc_extra_bits){

  569.             av_log(s->avctx, AV_LOG_ERROR, "Extra bits CRC error\n");

  570.             return -1;

  571.         }

  572.         wv_reset_saved_context(s);

  573.     }else{

  574.         s->pos = pos;

  575.         s->sc.crc = crc;

  576.         s->sc.bits_used = get_bits_count(&s->gb);

  577.         if(s->got_extra_bits){

  578.             s->extra_sc.crc = crc_extra_bits;

  579.             s->extra_sc.bits_used = get_bits_count(&s->gb_extra_bits);

  580.         }

  581.     }

  582.     return count * 2;

  583. }

  584. 

  585. static inline int wv_unpack_mono(WavpackContext *s, GetBitContext *gb, void *dst, const int type)

  586. {

  587.     int i, j, count = 0;

  588.     int last, t;

  589.     int A, S, T;

  590.     int pos = s->pos;

  591.     uint32_t crc = s->sc.crc;

  592.     uint32_t crc_extra_bits = s->extra_sc.crc;

  593.     int16_t *dst16 = dst;

  594.     int32_t *dst32 = dst;

  595.     float   *dstfl = dst;

  596. 

  597.     if(s->samples_left == s->samples)

  598.         s->one = s->zero = s->zeroes = 0;

  599.     do{

  600.         T = wv_get_value(s, gb, 0, &last);

  601.         S = 0;

  602.         if(last) break;

  603.         for(i = 0; i < s->terms; i++){

  604.             t = s->decorr[i].value;

  605.             if(t > 8){

  606.                 if(t & 1)

  607.                     A = 2 * s->decorr[i].samplesA[0] - s->decorr[i].samplesA[1];

  608.                 else

  609.                     A = (3 * s->decorr[i].samplesA[0] - s->decorr[i].samplesA[1]) >> 1;

  610.                 s->decorr[i].samplesA[1] = s->decorr[i].samplesA[0];

  611.                 j = 0;

  612.             }else{

  613.                 A = s->decorr[i].samplesA[pos];

  614.                 j = (pos + t) & 7;

  615.             }

  616.             if(type != SAMPLE_FMT_S16)

  617.                 S = T + ((s->decorr[i].weightA * (int64_t)A + 512) >> 10);

  618.             else

  619.                 S = T + ((s->decorr[i].weightA * A + 512) >> 10);

  620.             if(A && T) s->decorr[i].weightA -= ((((T ^ A) >> 30) & 2) - 1) * s->decorr[i].delta;

  621.             s->decorr[i].samplesA[j] = T = S;

  622.         }

  623.         pos = (pos + 1) & 7;

  624.         crc = crc * 3 + S;

  625. 

  626.         if(type == SAMPLE_FMT_FLT)

  627.             *dstfl++ = wv_get_value_float(s, &crc_extra_bits, S);

  628.         else if(type == SAMPLE_FMT_S32)

  629.             *dst32++ = wv_get_value_integer(s, &crc_extra_bits, S);

  630.         else

  631.             *dst16++ = wv_get_value_integer(s, &crc_extra_bits, S);

  632.         count++;

  633.     }while(!last && count < s->samples);

  634. 

  635.     s->samples_left -= count;

  636.     if(!s->samples_left){

  637.         if(crc != s->CRC){

  638.             av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");

  639.             return -1;

  640.         }

  641.         if(s->got_extra_bits && crc_extra_bits != s->crc_extra_bits){

  642.             av_log(s->avctx, AV_LOG_ERROR, "Extra bits CRC error\n");

  643.             return -1;

  644.         }

  645.         wv_reset_saved_context(s);

  646.     }else{

  647.         s->pos = pos;

  648.         s->sc.crc = crc;

  649.         s->sc.bits_used = get_bits_count(&s->gb);

  650.         if(s->got_extra_bits){

  651.             s->extra_sc.crc = crc_extra_bits;

  652.             s->extra_sc.bits_used = get_bits_count(&s->gb_extra_bits);

  653.         }

  654.     }

  655.     return count;

  656. }

  657. 

  658. static av_cold int wavpack_decode_init(AVCodecContext *avctx)

  659. {

  660.     WavpackContext *s = avctx->priv_data;

  661. 

  662.     s->avctx = avctx;

  663.     s->stereo = (avctx->channels == 2);

  664.     if(avctx->bits_per_coded_sample <= 16)

  665.         avctx->sample_fmt = SAMPLE_FMT_S16;

  666.     else

  667.         avctx->sample_fmt = SAMPLE_FMT_S32;

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

  669. 

  670.     wv_reset_saved_context(s);

  671. 

  672.     return 0;

  673. }

  674. 

  675. static int wavpack_decode_frame(AVCodecContext *avctx,

  676.                             void *data, int *data_size,

  677.                             AVPacket *avpkt)

  678. {

  679.     const uint8_t *buf = avpkt->data;

  680.     int buf_size = avpkt->size;

  681.     WavpackContext *s = avctx->priv_data;

  682.     void *samples = data;

  683.     int samplecount;

  684.     int got_terms = 0, got_weights = 0, got_samples = 0, got_entropy = 0, got_bs = 0, got_float = 0;

  685.     int got_hybrid = 0;

  686.     const uint8_t* buf_end = buf + buf_size;

  687.     int i, j, id, size, ssize, weights, t;

  688.     int bpp;

  689. 

  690.     if (buf_size == 0){

  691.         *data_size = 0;

  692.         return 0;

  693.     }

  694. 

  695.     if(!s->samples_left){

  696.         memset(s->decorr, 0, MAX_TERMS * sizeof(Decorr));

  697.         memset(s->ch, 0, sizeof(s->ch));

  698.         s->extra_bits = 0;

  699.         s->and = s->or = s->shift = 0;

  700.         s->got_extra_bits = 0;

  701.     }

  702. 

  703.     s->samples = AV_RL32(buf); buf += 4;

  704.     if(!s->samples){

  705.         *data_size = 0;

  706.         return buf_size;

  707.     }

  708.     s->frame_flags = AV_RL32(buf); buf += 4;

  709.     if(s->frame_flags&0x80){

  710.         bpp = sizeof(float);

  711.         avctx->sample_fmt = SAMPLE_FMT_FLT;

  712.     } else if((s->frame_flags&0x03) <= 1){

  713.         bpp = 2;

  714.         avctx->sample_fmt = SAMPLE_FMT_S16;

  715.     } else {

  716.         bpp = 4;

  717.         avctx->sample_fmt = SAMPLE_FMT_S32;

  718.     }

  719.     s->stereo_in = (s->frame_flags & WV_FALSE_STEREO) ? 0 : s->stereo;

  720.     s->joint = s->frame_flags & WV_JOINT_STEREO;

  721.     s->hybrid = s->frame_flags & WV_HYBRID_MODE;

  722.     s->hybrid_bitrate = s->frame_flags & WV_HYBRID_BITRATE;

  723.     s->post_shift = 8 * (bpp-1-(s->frame_flags&0x03)) + ((s->frame_flags >> 13) & 0x1f);

  724.     s->CRC = AV_RL32(buf); buf += 4;

  725. 

  726.     s->max_samples = *data_size / (bpp * avctx->channels);

  727.     s->max_samples = FFMIN(s->max_samples, s->samples);

  728.     if(s->samples_left > 0){

  729.         s->max_samples = FFMIN(s->max_samples, s->samples_left);

  730.         buf = buf_end;

  731.     }

  732. 

  733.     // parse metadata blocks

  734.     while(buf < buf_end){

  735.         id = *buf++;

  736.         size = *buf++;

  737.         if(id & WP_IDF_LONG) {

  738.             size |= (*buf++) << 8;

  739.             size |= (*buf++) << 16;

  740.         }

  741.         size <<= 1; // size is specified in words

  742.         ssize = size;

  743.         if(id & WP_IDF_ODD) size--;

  744.         if(size < 0){

  745.             av_log(avctx, AV_LOG_ERROR, "Got incorrect block %02X with size %i\n", id, size);

  746.             break;

  747.         }

  748.         if(buf + ssize > buf_end){

  749.             av_log(avctx, AV_LOG_ERROR, "Block size %i is out of bounds\n", size);

  750.             break;

  751.         }

  752.         if(id & WP_IDF_IGNORE){

  753.             buf += ssize;

  754.             continue;

  755.         }

  756.         switch(id & WP_IDF_MASK){

  757.         case WP_ID_DECTERMS:

  758.             s->terms = size;

  759.             if(s->terms > MAX_TERMS){

  760.                 av_log(avctx, AV_LOG_ERROR, "Too many decorrelation terms\n");

  761.                 buf += ssize;

  762.                 continue;

  763.             }

  764.             for(i = 0; i < s->terms; i++) {

  765.                 s->decorr[s->terms - i - 1].value = (*buf & 0x1F) - 5;

  766.                 s->decorr[s->terms - i - 1].delta = *buf >> 5;

  767.                 buf++;

  768.             }

  769.             got_terms = 1;

  770.             break;

  771.         case WP_ID_DECWEIGHTS:

  772.             if(!got_terms){

  773.                 av_log(avctx, AV_LOG_ERROR, "No decorrelation terms met\n");

  774.                 continue;

  775.             }

  776.             weights = size >> s->stereo_in;

  777.             if(weights > MAX_TERMS || weights > s->terms){

  778.                 av_log(avctx, AV_LOG_ERROR, "Too many decorrelation weights\n");

  779.                 buf += ssize;

  780.                 continue;

  781.             }

  782.             for(i = 0; i < weights; i++) {

  783.                 t = (int8_t)(*buf++);

  784.                 s->decorr[s->terms - i - 1].weightA = t << 3;

  785.                 if(s->decorr[s->terms - i - 1].weightA > 0)

  786.                     s->decorr[s->terms - i - 1].weightA += (s->decorr[s->terms - i - 1].weightA + 64) >> 7;

  787.                 if(s->stereo_in){

  788.                     t = (int8_t)(*buf++);

  789.                     s->decorr[s->terms - i - 1].weightB = t << 3;

  790.                     if(s->decorr[s->terms - i - 1].weightB > 0)

  791.                         s->decorr[s->terms - i - 1].weightB += (s->decorr[s->terms - i - 1].weightB + 64) >> 7;

  792.                 }

  793.             }

  794.             got_weights = 1;

  795.             break;

  796.         case WP_ID_DECSAMPLES:

  797.             if(!got_terms){

  798.                 av_log(avctx, AV_LOG_ERROR, "No decorrelation terms met\n");

  799.                 continue;

  800.             }

  801.             t = 0;

  802.             for(i = s->terms - 1; (i >= 0) && (t < size); i--) {

  803.                 if(s->decorr[i].value > 8){

  804.                     s->decorr[i].samplesA[0] = wp_exp2(AV_RL16(buf)); buf += 2;

  805.                     s->decorr[i].samplesA[1] = wp_exp2(AV_RL16(buf)); buf += 2;

  806.                     if(s->stereo_in){

  807.                         s->decorr[i].samplesB[0] = wp_exp2(AV_RL16(buf)); buf += 2;

  808.                         s->decorr[i].samplesB[1] = wp_exp2(AV_RL16(buf)); buf += 2;

  809.                         t += 4;

  810.                     }

  811.                     t += 4;

  812.                 }else if(s->decorr[i].value < 0){

  813.                     s->decorr[i].samplesA[0] = wp_exp2(AV_RL16(buf)); buf += 2;

  814.                     s->decorr[i].samplesB[0] = wp_exp2(AV_RL16(buf)); buf += 2;

  815.                     t += 4;

  816.                 }else{

  817.                     for(j = 0; j < s->decorr[i].value; j++){

  818.                         s->decorr[i].samplesA[j] = wp_exp2(AV_RL16(buf)); buf += 2;

  819.                         if(s->stereo_in){

  820.                             s->decorr[i].samplesB[j] = wp_exp2(AV_RL16(buf)); buf += 2;

  821.                         }

  822.                     }

  823.                     t += s->decorr[i].value * 2 * (s->stereo_in + 1);

  824.                 }

  825.             }

  826.             got_samples = 1;

  827.             break;

  828.         case WP_ID_ENTROPY:

  829.             if(size != 6 * (s->stereo_in + 1)){

  830.                 av_log(avctx, AV_LOG_ERROR, "Entropy vars size should be %i, got %i", 6 * (s->stereo_in + 1), size);

  831.                 buf += ssize;

  832.                 continue;

  833.             }

  834.             for(j = 0; j <= s->stereo_in; j++){

  835.                 for(i = 0; i < 3; i++){

  836.                     s->ch[j].median[i] = wp_exp2(AV_RL16(buf));

  837.                     buf += 2;

  838.                 }

  839.             }

  840.             got_entropy = 1;

  841.             break;

  842.         case WP_ID_HYBRID:

  843.             if(s->hybrid_bitrate){

  844.                 for(i = 0; i <= s->stereo_in; i++){

  845.                     s->ch[i].slow_level = wp_exp2(AV_RL16(buf));

  846.                     buf += 2;

  847.                     size -= 2;

  848.                 }

  849.             }

  850.             for(i = 0; i < (s->stereo_in + 1); i++){

  851.                 s->ch[i].bitrate_acc = AV_RL16(buf) << 16;

  852.                 buf += 2;

  853.                 size -= 2;

  854.             }

  855.             if(size > 0){

  856.                 for(i = 0; i < (s->stereo_in + 1); i++){

  857.                     s->ch[i].bitrate_delta = wp_exp2((int16_t)AV_RL16(buf));

  858.                     buf += 2;

  859.                 }

  860.             }else{

  861.                 for(i = 0; i < (s->stereo_in + 1); i++)

  862.                     s->ch[i].bitrate_delta = 0;

  863.             }

  864.             got_hybrid = 1;

  865.             break;

  866.         case WP_ID_INT32INFO:

  867.             if(size != 4){

  868.                 av_log(avctx, AV_LOG_ERROR, "Invalid INT32INFO, size = %i, sent_bits = %i\n", size, *buf);

  869.                 buf += ssize;

  870.                 continue;

  871.             }

  872.             if(buf[0])

  873.                 s->extra_bits = buf[0];

  874.             else if(buf[1])

  875.                 s->shift = buf[1];

  876.             else if(buf[2]){

  877.                 s->and = s->or = 1;

  878.                 s->shift = buf[2];

  879.             }else if(buf[3]){

  880.                 s->and = 1;

  881.                 s->shift = buf[3];

  882.             }

  883.             buf += 4;

  884.             break;

  885.         case WP_ID_FLOATINFO:

  886.             if(size != 4){

  887.                 av_log(avctx, AV_LOG_ERROR, "Invalid FLOATINFO, size = %i\n", size);

  888.                 buf += ssize;

  889.                 continue;

  890.             }

  891.             s->float_flag = buf[0];

  892.             s->float_shift = buf[1];

  893.             s->float_max_exp = buf[2];

  894.             buf += 4;

  895.             got_float = 1;

  896.             break;

  897.         case WP_ID_DATA:

  898.             s->sc.offset = buf - avpkt->data;

  899.             s->sc.size   = size * 8;

  900.             init_get_bits(&s->gb, buf, size * 8);

  901.             s->data_size = size * 8;

  902.             buf += size;

  903.             got_bs = 1;

  904.             break;

  905.         case WP_ID_EXTRABITS:

  906.             if(size <= 4){

  907.                 av_log(avctx, AV_LOG_ERROR, "Invalid EXTRABITS, size = %i\n", size);

  908.                 buf += size;

  909.                 continue;

  910.             }

  911.             s->extra_sc.offset = buf - avpkt->data;

  912.             s->extra_sc.size   = size * 8;

  913.             init_get_bits(&s->gb_extra_bits, buf, size * 8);

  914.             s->crc_extra_bits = get_bits_long(&s->gb_extra_bits, 32);

  915.             buf += size;

  916.             s->got_extra_bits = 1;

  917.             break;

  918.         default:

  919.             buf += size;

  920.         }

  921.         if(id & WP_IDF_ODD) buf++;

  922.     }

  923.     if(!s->samples_left){

  924.         if(!got_terms){

  925.             av_log(avctx, AV_LOG_ERROR, "No block with decorrelation terms\n");

  926.             return -1;

  927.         }

  928.         if(!got_weights){

  929.             av_log(avctx, AV_LOG_ERROR, "No block with decorrelation weights\n");

  930.             return -1;

  931.         }

  932.         if(!got_samples){

  933.             av_log(avctx, AV_LOG_ERROR, "No block with decorrelation samples\n");

  934.             return -1;

  935.         }

  936.         if(!got_entropy){

  937.             av_log(avctx, AV_LOG_ERROR, "No block with entropy info\n");

  938.             return -1;

  939.         }

  940.         if(s->hybrid && !got_hybrid){

  941.             av_log(avctx, AV_LOG_ERROR, "Hybrid config not found\n");

  942.             return -1;

  943.         }

  944.         if(!got_bs){

  945.             av_log(avctx, AV_LOG_ERROR, "Packed samples not found\n");

  946.             return -1;

  947.         }

  948.         if(!got_float && avctx->sample_fmt == SAMPLE_FMT_FLT){

  949.             av_log(avctx, AV_LOG_ERROR, "Float information not found\n");

  950.             return -1;

  951.         }

  952.         if(s->got_extra_bits && avctx->sample_fmt != SAMPLE_FMT_FLT){

  953.             const int size = get_bits_left(&s->gb_extra_bits);

  954.             const int wanted = s->samples * s->extra_bits << s->stereo_in;

  955.             if(size < wanted){

  956.                 av_log(avctx, AV_LOG_ERROR, "Too small EXTRABITS\n");

  957.                 s->got_extra_bits = 0;

  958.             }

  959.         }

  960.         s->samples_left = s->samples;

  961.     }else{

  962.         init_get_bits(&s->gb, avpkt->data + s->sc.offset, s->sc.size);

  963.         skip_bits_long(&s->gb, s->sc.bits_used);

  964.         if(s->got_extra_bits){

  965.             init_get_bits(&s->gb_extra_bits, avpkt->data + s->extra_sc.offset,

  966.                           s->extra_sc.size);

  967.             skip_bits_long(&s->gb_extra_bits, s->extra_sc.bits_used);

  968.         }

  969.     }

  970. 

  971.     if(s->stereo_in){

  972.         if(avctx->sample_fmt == SAMPLE_FMT_S16)

  973.             samplecount = wv_unpack_stereo(s, &s->gb, samples, SAMPLE_FMT_S16);

  974.         else if(avctx->sample_fmt == SAMPLE_FMT_S32)

  975.             samplecount = wv_unpack_stereo(s, &s->gb, samples, SAMPLE_FMT_S32);

  976.         else

  977.             samplecount = wv_unpack_stereo(s, &s->gb, samples, SAMPLE_FMT_FLT);

  978. 

  979.     }else{

  980.         if(avctx->sample_fmt == SAMPLE_FMT_S16)

  981.             samplecount = wv_unpack_mono(s, &s->gb, samples, SAMPLE_FMT_S16);

  982.         else if(avctx->sample_fmt == SAMPLE_FMT_S32)

  983.             samplecount = wv_unpack_mono(s, &s->gb, samples, SAMPLE_FMT_S32);

  984.         else

  985.             samplecount = wv_unpack_mono(s, &s->gb, samples, SAMPLE_FMT_FLT);

  986. 

  987.         if(s->stereo && avctx->sample_fmt == SAMPLE_FMT_S16){

  988.             int16_t *dst = (int16_t*)samples + samplecount * 2;

  989.             int16_t *src = (int16_t*)samples + samplecount;

  990.             int cnt = samplecount;

  991.             while(cnt--){

  992.                 *--dst = *--src;

  993.                 *--dst = *src;

  994.             }

  995.             samplecount *= 2;

  996.         }else if(s->stereo && avctx->sample_fmt == SAMPLE_FMT_S32){

  997.             int32_t *dst = (int32_t*)samples + samplecount * 2;

  998.             int32_t *src = (int32_t*)samples + samplecount;

  999.             int cnt = samplecount;

  1000.             while(cnt--){

  1001.                 *--dst = *--src;

  1002.                 *--dst = *src;

  1003.             }

  1004.             samplecount *= 2;

  1005.         }else if(s->stereo){

  1006.             float *dst = (float*)samples + samplecount * 2;

  1007.             float *src = (float*)samples + samplecount;

  1008.             int cnt = samplecount;

  1009.             while(cnt--){

  1010.                 *--dst = *--src;

  1011.                 *--dst = *src;

  1012.             }

  1013.             samplecount *= 2;

  1014.         }

  1015.     }

  1016.     *data_size = samplecount * bpp;

  1017. 

  1018.     return s->samples_left > 0 ? 0 : buf_size;

  1019. }

  1020. 

  1021. AVCodec wavpack_decoder = {

  1022.     "wavpack",

  1023.     AVMEDIA_TYPE_AUDIO,

  1024.     CODEC_ID_WAVPACK,

  1025.     sizeof(WavpackContext),

  1026.     wavpack_decode_init,

  1027.     NULL,

  1028.     NULL,

  1029.     wavpack_decode_frame,

  1030.     .capabilities = CODEC_CAP_SUBFRAMES,

  1031.     .long_name = NULL_IF_CONFIG_SMALL("WavPack"),

  1032. };