PeerStreamer

/*

 * WavPack lossless audio decoder

 * Copyright (c) 2006,2011 Konstantin Shishkov

 *

 * This file is part of FFmpeg.

 *

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

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

 * License as published by the Free Software Foundation; either

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

 *

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

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

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

 * Lesser General Public License for more details.

 *

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

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

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

 */

#define ALT_BITSTREAM_READER_LE

#include "avcodec.h"

#include "get_bits.h"

#include "unary.h"

#include "libavcore/audioconvert.h"

/**

 * @file

 * WavPack lossless audio decoder

 */

#define WV_MONO         0x00000004

#define WV_JOINT_STEREO 0x00000010

#define WV_FALSE_STEREO 0x40000000

#define WV_HYBRID_MODE    0x00000008

#define WV_HYBRID_SHAPE   0x00000008

#define WV_HYBRID_BITRATE 0x00000200

#define WV_HYBRID_BALANCE 0x00000400

#define WV_FLT_SHIFT_ONES 0x01

#define WV_FLT_SHIFT_SAME 0x02

#define WV_FLT_SHIFT_SENT 0x04

#define WV_FLT_ZERO_SENT  0x08

#define WV_FLT_ZERO_SIGN  0x10

enum WP_ID_Flags{

    WP_IDF_MASK   = 0x1F,

    WP_IDF_IGNORE = 0x20,

    WP_IDF_ODD    = 0x40,

    WP_IDF_LONG   = 0x80

};

enum WP_ID{

    WP_ID_DUMMY = 0,

    WP_ID_ENCINFO,

    WP_ID_DECTERMS,

    WP_ID_DECWEIGHTS,

    WP_ID_DECSAMPLES,

    WP_ID_ENTROPY,

    WP_ID_HYBRID,

    WP_ID_SHAPING,

    WP_ID_FLOATINFO,

    WP_ID_INT32INFO,

    WP_ID_DATA,

    WP_ID_CORR,

    WP_ID_EXTRABITS,

    WP_ID_CHANINFO

};

typedef struct SavedContext {

    int offset;

    int size;

    int bits_used;

    uint32_t crc;

} SavedContext;

#define MAX_TERMS 16

typedef struct Decorr {

    int delta;

    int value;

    int weightA;

    int weightB;

    int samplesA[8];

    int samplesB[8];

} Decorr;

typedef struct WvChannel {

    int median[3];

    int slow_level, error_limit;

    int bitrate_acc, bitrate_delta;

} WvChannel;

typedef struct WavpackFrameContext {

    AVCodecContext *avctx;

    int frame_flags;

    int stereo, stereo_in;

    int joint;

    uint32_t CRC;

    GetBitContext gb;

    int got_extra_bits;

    uint32_t crc_extra_bits;

    GetBitContext gb_extra_bits;

    int data_size; // in bits

    int samples;

    int terms;

    Decorr decorr[MAX_TERMS];

    int zero, one, zeroes;

    int extra_bits;

    int and, or, shift;

    int post_shift;

    int hybrid, hybrid_bitrate;

    int float_flag;

    int float_shift;

    int float_max_exp;

    WvChannel ch[2];

    int samples_left;

    int max_samples;

    int pos;

    SavedContext sc, extra_sc;

} WavpackFrameContext;

#define WV_MAX_FRAME_DECODERS 14

typedef struct WavpackContext {

    AVCodecContext *avctx;

    WavpackFrameContext *fdec[WV_MAX_FRAME_DECODERS];

    int fdec_num;

    int multichannel;

    int mkv_mode;

    int block;

    int samples;

    int samples_left;

    int ch_offset;

} WavpackContext;

// exponent table copied from WavPack source

static const uint8_t wp_exp2_table [256] = {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

};

static const uint8_t wp_log2_table [] = {

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

};

static av_always_inline int wp_exp2(int16_t val)

{

    int res, neg = 0;

    if(val < 0){

        val = -val;

        neg = 1;

    }

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

    val >>= 8;

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

    return neg ? -res : res;

}

static av_always_inline int wp_log2(int32_t val)

{

    int bits;

    if(!val)

        return 0;

    if(val == 1)

        return 256;

    val += val >> 9;

    bits = av_log2(val) + 1;

    if(bits < 9)

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

    else

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

}

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

// macros for manipulating median values

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

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

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

// macros for applying weight

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

        if(samples && in){ \

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

                weight -= delta; \

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

            }else{ \

                weight += delta; \

                if(weight > 1024) weight = 1024; \

            } \

        }

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

{

    int p, e, res;

    if(k<1)return 0;

    p = av_log2(k);

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

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

    if(res >= e){

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

    }

    return res;

}

static void update_error_limit(WavpackFrameContext *ctx)

{

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

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

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

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

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

    }

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

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

        if(balance > br[0]){

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

            br[0] = 0;

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

            br[0] <<= 1;

            br[1] = 0;

        }else{

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

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

        }

    }

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

        if(ctx->hybrid_bitrate){

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

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

            else

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

        }else{

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

        }

    }

}

static int wv_get_value(WavpackFrameContext *ctx, GetBitContext *gb, int channel, int *last)

{

    int t, t2;

    int sign, base, add, ret;

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

    *last = 0;

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

        if(ctx->zeroes){

            ctx->zeroes--;

            if(ctx->zeroes){

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

                return 0;

            }

        }else{

            t = get_unary_0_33(gb);

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

            ctx->zeroes = t;

            if(ctx->zeroes){

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

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

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

                return 0;

            }

        }

    }

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

        *last = 1;

        return 0;

    }

    if(ctx->zero){

        t = 0;

        ctx->zero = 0;

    }else{

        t = get_unary_0_33(gb);

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

            *last = 1;

            return 0;

        }

        if(t == 16) {

            t2 = get_unary_0_33(gb);

            if(t2 < 2) t += t2;

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

        }

        if(ctx->one){

            ctx->one = t&1;

            t = (t>>1) + 1;

        }else{

            ctx->one = t&1;

            t >>= 1;

        }

        ctx->zero = !ctx->one;

    }

    if(ctx->hybrid && !channel)

        update_error_limit(ctx);

    if(!t){

        base = 0;

        add = GET_MED(0) - 1;

        DEC_MED(0);

    }else if(t == 1){

        base = GET_MED(0);

        add = GET_MED(1) - 1;

        INC_MED(0);

        DEC_MED(1);

    }else if(t == 2){

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

        add = GET_MED(2) - 1;

        INC_MED(0);

        INC_MED(1);

        DEC_MED(2);

    }else{

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

        add = GET_MED(2) - 1;

        INC_MED(0);

        INC_MED(1);

        INC_MED(2);

    }

    if(!c->error_limit){

        ret = base + get_tail(gb, add);

    }else{

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

        while(add > c->error_limit){

            if(get_bits1(gb)){

                add -= (mid - base);

                base = mid;

            }else

                add = mid - base - 1;

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

        }

        ret = mid;

    }

    sign = get_bits1(gb);

    if(ctx->hybrid_bitrate)

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

    return sign ? ~ret : ret;

}

static inline int wv_get_value_integer(WavpackFrameContext *s, uint32_t *crc, int S)

{

    int bit;

    if(s->extra_bits){

        S <<= s->extra_bits;

        if(s->got_extra_bits){

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

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

        }

    }

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

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

}

static float wv_get_value_float(WavpackFrameContext *s, uint32_t *crc, int S)

{

    union {

        float    f;

        uint32_t u;

    } value;

    int sign;

    int exp = s->float_max_exp;

    if(s->got_extra_bits){

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

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

        if(left_bits + 8 * FF_INPUT_BUFFER_PADDING_SIZE < max_bits)

            return 0.0;

    }

    if(S){

        S <<= s->float_shift;

        sign = S < 0;

        if(sign)

            S = -S;

        if(S >= 0x1000000){

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

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

            }else{

                S = 0;

            }

            exp = 255;

        }else if(exp){

            int shift = 23 - av_log2(S);

            exp = s->float_max_exp;

            if(exp <= shift){

                shift = --exp;

            }

            exp -= shift;

            if(shift){

                S <<= shift;

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

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

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

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

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

                }

            }

        }else{

            exp = s->float_max_exp;

        }

        S &= 0x7fffff;

    }else{

        sign = 0;

        exp = 0;

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

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

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

                if(s->float_max_exp >= 25)

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

                sign = get_bits1(&s->gb_extra_bits);

            }else{

                if(s->float_flag & WV_FLT_ZERO_SIGN)

                    sign = get_bits1(&s->gb_extra_bits);

            }

        }

    }

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

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

    return value.f;

}

static void wv_reset_saved_context(WavpackFrameContext *s)

{

    s->pos = 0;

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

}

static inline int wv_unpack_stereo(WavpackFrameContext *s, GetBitContext *gb, void *dst, const int type)

{

    int i, j, count = 0;

    int last, t;

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

    int pos = s->pos;

    uint32_t crc = s->sc.crc;

    uint32_t crc_extra_bits = s->extra_sc.crc;

    int16_t *dst16 = dst;

    int32_t *dst32 = dst;

    float   *dstfl = dst;

    const int channel_pad = s->avctx->channels - 2;

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

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

    do{

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

        if(last) break;

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

        if(last) break;

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

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

            if(t > 0){

                if(t > 8){

                    if(t & 1){

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

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

                    }else{

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

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

                    }

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

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

                    j = 0;

                }else{

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

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

                    j = (pos + t) & 7;

                }

                if(type != AV_SAMPLE_FMT_S16){

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

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

                }else{

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

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

                }

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

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

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

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

            }else if(t == -1){

                if(type != AV_SAMPLE_FMT_S16)

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

                else

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

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

                L = L2;

                if(type != AV_SAMPLE_FMT_S16)

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

                else

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

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

                R = R2;

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

            }else{

                if(type != AV_SAMPLE_FMT_S16)

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

                else

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

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

                R = R2;

                if(t == -3){

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

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

                }

                if(type != AV_SAMPLE_FMT_S16)

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

                else

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

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

                L = L2;

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

            }

        }

        pos = (pos + 1) & 7;

        if(s->joint)

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

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

        if(type == AV_SAMPLE_FMT_FLT){

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

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

            dstfl += channel_pad;

        } else if(type == AV_SAMPLE_FMT_S32){

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

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

            dst32 += channel_pad;

        } else {

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

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

            dst16 += channel_pad;

        }

        count++;

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

    s->samples_left -= count;

    if(!s->samples_left){

        if(crc != s->CRC){

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

            return -1;

        }

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

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

            return -1;

        }

        wv_reset_saved_context(s);

    }else{

        s->pos = pos;

        s->sc.crc = crc;

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

        if(s->got_extra_bits){

            s->extra_sc.crc = crc_extra_bits;

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

        }

    }

    return count * 2;

}

static inline int wv_unpack_mono(WavpackFrameContext *s, GetBitContext *gb, void *dst, const int type)

{

    int i, j, count = 0;

    int last, t;

    int A, S, T;

    int pos = s->pos;

    uint32_t crc = s->sc.crc;

    uint32_t crc_extra_bits = s->extra_sc.crc;

    int16_t *dst16 = dst;

    int32_t *dst32 = dst;

    float   *dstfl = dst;

    const int channel_stride = s->avctx->channels;

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

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

    do{

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

        S = 0;

        if(last) break;

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

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

            if(t > 8){

                if(t & 1)

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

                else

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

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

                j = 0;

            }else{

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

                j = (pos + t) & 7;

            }

            if(type != AV_SAMPLE_FMT_S16)

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

            else

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

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

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

        }

        pos = (pos + 1) & 7;

        crc = crc * 3 + S;

        if(type == AV_SAMPLE_FMT_FLT){

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

            dstfl += channel_stride;

        }else if(type == AV_SAMPLE_FMT_S32){

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

            dst32 += channel_stride;

        }else{

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

            dst16 += channel_stride;

        }

        count++;

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

    s->samples_left -= count;

    if(!s->samples_left){

        if(crc != s->CRC){

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

            return -1;

        }

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

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

            return -1;

        }

        wv_reset_saved_context(s);

    }else{

        s->pos = pos;

        s->sc.crc = crc;

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

        if(s->got_extra_bits){

            s->extra_sc.crc = crc_extra_bits;

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

        }

    }

    return count;

}

static av_cold int wv_alloc_frame_context(WavpackContext *c)

{

    if(c->fdec_num == WV_MAX_FRAME_DECODERS)

        return -1;

    c->fdec[c->fdec_num] = av_mallocz(sizeof(**c->fdec));

    if(!c->fdec[c->fdec_num])

        return -1;

    c->fdec_num++;

    c->fdec[c->fdec_num - 1]->avctx = c->avctx;

    wv_reset_saved_context(c->fdec[c->fdec_num - 1]);

    return 0;

}

static av_cold int wavpack_decode_init(AVCodecContext *avctx)

{

    WavpackContext *s = avctx->priv_data;

    s->avctx = avctx;

    if(avctx->bits_per_coded_sample <= 16)

        avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    else

        avctx->sample_fmt = AV_SAMPLE_FMT_S32;

    if(avctx->channels <= 2 && !avctx->channel_layout)

        avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;

    s->multichannel = avctx->channels > 2;

    /* lavf demuxer does not provide extradata, Matroska stores 0x403

       there, use this to detect decoding mode for multichannel */

    s->mkv_mode = 0;

    if(s->multichannel && avctx->extradata && avctx->extradata_size == 2){

        int ver = AV_RL16(avctx->extradata);

        if(ver >= 0x402 && ver <= 0x410)

            s->mkv_mode = 1;

    }

    s->fdec_num = 0;

    return 0;

}

static av_cold int wavpack_decode_end(AVCodecContext *avctx)

{

    WavpackContext *s = avctx->priv_data;

    int i;

    for(i = 0; i < s->fdec_num; i++)

        av_freep(&s->fdec[i]);

    s->fdec_num = 0;

    return 0;

}

static int wavpack_decode_block(AVCodecContext *avctx, int block_no,

                                void *data, int *data_size,

                                const uint8_t *buf, int buf_size)

{

    WavpackContext *wc = avctx->priv_data;

    WavpackFrameContext *s;

    void *samples = data;

    int samplecount;

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

    int got_hybrid = 0;

    const uint8_t* orig_buf = buf;

    const uint8_t* buf_end = buf + buf_size;

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

    int bpp, chan, chmask;

    if (buf_size == 0){

        *data_size = 0;

        return 0;

    }

    if(block_no >= wc->fdec_num && wv_alloc_frame_context(wc) < 0){

        av_log(avctx, AV_LOG_ERROR, "Error creating frame decode context\n");

        return -1;

    }

    s = wc->fdec[block_no];

    if(!s){

        av_log(avctx, AV_LOG_ERROR, "Context for block %d is not present\n", block_no);

        return -1;

    }

    if(!s->samples_left){

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

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

        s->extra_bits = 0;

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

        s->got_extra_bits = 0;

    }

    if(!wc->mkv_mode){

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

        if(!s->samples){

            *data_size = 0;

            return buf_size;

        }

    }else{

        s->samples = wc->samples;

    }

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

    if(s->frame_flags&0x80){

        bpp = sizeof(float);

        avctx->sample_fmt = AV_SAMPLE_FMT_FLT;

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

        bpp = 2;

        avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    } else {

        bpp = 4;

        avctx->sample_fmt = AV_SAMPLE_FMT_S32;

    }

    samples = (uint8_t*)samples + bpp * wc->ch_offset;

    s->stereo = !(s->frame_flags & WV_MONO);

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

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

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

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

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

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

    if(wc->mkv_mode)

        buf += 4; //skip block size;

    wc->ch_offset += 1 + s->stereo;

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

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

    if(s->samples_left > 0){

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

        buf = buf_end;

    }

    // parse metadata blocks

    while(buf < buf_end){

        id = *buf++;

        size = *buf++;

        if(id & WP_IDF_LONG) {

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

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

        }

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

        ssize = size;

        if(id & WP_IDF_ODD) size--;

        if(size < 0){

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

            break;

        }

        if(buf + ssize > buf_end){

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

            break;

        }

        if(id & WP_IDF_IGNORE){

            buf += ssize;

            continue;

        }

        switch(id & WP_IDF_MASK){

        case WP_ID_DECTERMS:

            s->terms = size;

            if(s->terms > MAX_TERMS){

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

                buf += ssize;

                continue;

            }

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

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

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

                buf++;

            }

            got_terms = 1;

            break;

        case WP_ID_DECWEIGHTS:

            if(!got_terms){

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

                continue;

            }

            weights = size >> s->stereo_in;

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

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

                buf += ssize;

                continue;

            }

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

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

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

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

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

                if(s->stereo_in){

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

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

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

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

                }

            }

            got_weights = 1;

            break;

        case WP_ID_DECSAMPLES:

            if(!got_terms){

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

                continue;

            }

            t = 0;

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

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

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

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

                    if(s->stereo_in){

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

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

                        t += 4;

                    }

                    t += 4;

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

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

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

                    t += 4;

                }else{

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

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

                        if(s->stereo_in){

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

                        }

                    }

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

                }

            }

            got_samples = 1;

            break;

        case WP_ID_ENTROPY:

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

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

                buf += ssize;

                continue;

            }

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

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

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

                    buf += 2;

                }

            }

            got_entropy = 1;

            break;

        case WP_ID_HYBRID:

            if(s->hybrid_bitrate){

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

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

                    buf += 2;

                    size -= 2;

                }

            }

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

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

                buf += 2;

                size -= 2;

            }

            if(size > 0){

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

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

                    buf += 2;

                }

            }else{

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

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

            }

            got_hybrid = 1;

            break;

        case WP_ID_INT32INFO:

            if(size != 4){

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

                buf += ssize;

                continue;

            }

            if(buf[0])

                s->extra_bits = buf[0];

            else if(buf[1])

                s->shift = buf[1];

            else if(buf[2]){

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

                s->shift = buf[2];

            }else if(buf[3]){

                s->and = 1;

                s->shift = buf[3];

            }

            buf += 4;

            break;

        case WP_ID_FLOATINFO:

            if(size != 4){

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

                buf += ssize;

                continue;

            }

            s->float_flag = buf[0];

            s->float_shift = buf[1];

            s->float_max_exp = buf[2];

            buf += 4;

            got_float = 1;

            break;

        case WP_ID_DATA:

            s->sc.offset = buf - orig_buf;

            s->sc.size   = size * 8;

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

            s->data_size = size * 8;

            buf += size;

            got_bs = 1;

            break;

        case WP_ID_EXTRABITS:

            if(size <= 4){

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

                buf += size;

                continue;

            }

            s->extra_sc.offset = buf - orig_buf;

            s->extra_sc.size   = size * 8;

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

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

            buf += size;

            s->got_extra_bits = 1;

            break;

        case WP_ID_CHANINFO:

            if(size <= 1){

                av_log(avctx, AV_LOG_ERROR, "Insufficient channel information\n");

                return -1;

            }

            chan = *buf++;

            switch(size - 2){

            case 0:

                chmask = *buf;

                break;

            case 1:

                chmask = AV_RL16(buf);

                break;

            case 2:

                chmask = AV_RL24(buf);

                break;

            case 3:

                chmask = AV_RL32(buf);

                break;

            case 5:

                chan |= (buf[1] & 0xF) << 8;

                chmask = AV_RL24(buf + 2);

                break;

            default:

                av_log(avctx, AV_LOG_ERROR, "Invalid channel info size %d\n", size);

                chan = avctx->channels;

                chmask = avctx->channel_layout;

            }

            if(chan != avctx->channels){

                av_log(avctx, AV_LOG_ERROR, "Block reports total %d channels, decoder believes it's %d channels\n",

                       chan, avctx->channels);

                return -1;

            }

            if(!avctx->channel_layout)

                avctx->channel_layout = chmask;

            buf += size - 1;

            break;

        default:

            buf += size;

        }

        if(id & WP_IDF_ODD) buf++;

    }

    if(!s->samples_left){

        if(!got_terms){

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

            return -1;

        }

        if(!got_weights){

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

            return -1;

        }

        if(!got_samples){

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

            return -1;

        }

        if(!got_entropy){

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

            return -1;

        }

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

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

            return -1;

        }

        if(!got_bs){

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

            return -1;

        }

        if(!got_float && avctx->sample_fmt == AV_SAMPLE_FMT_FLT){

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

            return -1;

        }

        if(s->got_extra_bits && avctx->sample_fmt != AV_SAMPLE_FMT_FLT){

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

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

            if(size < wanted){

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

                s->got_extra_bits = 0;

            }

        }

        s->samples_left = s->samples;

    }else{

        init_get_bits(&s->gb, orig_buf + s->sc.offset, s->sc.size);

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

        if(s->got_extra_bits){

            init_get_bits(&s->gb_extra_bits, orig_buf + s->extra_sc.offset,

                          s->extra_sc.size);

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

        }

    }

    if(s->stereo_in){

        if(avctx->sample_fmt == AV_SAMPLE_FMT_S16)

            samplecount = wv_unpack_stereo(s, &s->gb, samples, AV_SAMPLE_FMT_S16);

        else if(avctx->sample_fmt == AV_SAMPLE_FMT_S32)

            samplecount = wv_unpack_stereo(s, &s->gb, samples, AV_SAMPLE_FMT_S32);

        else

            samplecount = wv_unpack_stereo(s, &s->gb, samples, AV_SAMPLE_FMT_FLT);

        samplecount >>= 1;

    }else{

        const int channel_stride = avctx->channels;

        if(avctx->sample_fmt == AV_SAMPLE_FMT_S16)

            samplecount = wv_unpack_mono(s, &s->gb, samples, AV_SAMPLE_FMT_S16);

        else if(avctx->sample_fmt == AV_SAMPLE_FMT_S32)

            samplecount = wv_unpack_mono(s, &s->gb, samples, AV_SAMPLE_FMT_S32);

        else

            samplecount = wv_unpack_mono(s, &s->gb, samples, AV_SAMPLE_FMT_FLT);

        if(s->stereo && avctx->sample_fmt == AV_SAMPLE_FMT_S16){

            int16_t *dst = (int16_t*)samples + 1;

            int16_t *src = (int16_t*)samples;

            int cnt = samplecount;

            while(cnt--){

                *dst = *src;

                src += channel_stride;

                dst += channel_stride;

            }

        }else if(s->stereo && avctx->sample_fmt == AV_SAMPLE_FMT_S32){

            int32_t *dst = (int32_t*)samples + 1;

            int32_t *src = (int32_t*)samples;

            int cnt = samplecount;

            while(cnt--){

                *dst = *src;

                src += channel_stride;

                dst += channel_stride;

            }

        }else if(s->stereo){

            float *dst = (float*)samples + 1;

            float *src = (float*)samples;

            int cnt = samplecount;

            while(cnt--){

                *dst = *src;

                src += channel_stride;

                dst += channel_stride;

            }

        }

    }

    wc->samples_left = s->samples_left;

    return samplecount * bpp;

}

static int wavpack_decode_frame(AVCodecContext *avctx,

                            void *data, int *data_size,

                            AVPacket *avpkt)

{

    WavpackContext *s = avctx->priv_data;

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    int frame_size;

    int samplecount = 0;

    s->block = 0;

    s->samples_left = 0;

    s->ch_offset = 0;

    if(s->mkv_mode){

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

    }

    while(buf_size > 0){

        if(!s->multichannel){

            frame_size = buf_size;

        }else{

            if(!s->mkv_mode){

                frame_size = AV_RL32(buf) - 12; buf += 4; buf_size -= 4;

            }else{

                if(buf_size < 12) //MKV files can have zero flags after last block

                    break;

                frame_size = AV_RL32(buf + 8) + 12;

            }

        }

        if(frame_size < 0 || frame_size > buf_size){

            av_log(avctx, AV_LOG_ERROR, "Block %d has invalid size (size %d vs. %d bytes left)\n",

                   s->block, frame_size, buf_size);

            return -1;

        }

        if((samplecount = wavpack_decode_block(avctx, s->block, data,

                                               data_size, buf, frame_size)) < 0)

            return -1;

        s->block++;

        buf += frame_size; buf_size -= frame_size;

    }

    *data_size = samplecount * avctx->channels;

    return s->samples_left > 0 ? 0 : avpkt->size;

}

AVCodec ff_wavpack_decoder = {

    "wavpack",

    AVMEDIA_TYPE_AUDIO,

    CODEC_ID_WAVPACK,

    sizeof(WavpackContext),

    wavpack_decode_init,

    NULL,

    wavpack_decode_end,

    wavpack_decode_frame,

    .capabilities = CODEC_CAP_SUBFRAMES,

    .long_name = NULL_IF_CONFIG_SMALL("WavPack"),

};