shithub: mp3dec

ref: 3d5ff1055544ceb54ab19d68d8f08990b636edd0
dir: /minimp3.c/

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#include "minimp3.h"

#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#define MAX_FREE_FORMAT_FRAME_SIZE  2304    // more than ISO spec's
#define MAX_FRAME_SYNC_MATCHES      10

#define MAX_L3_FRAME_PAYLOAD_BYTES  MAX_FREE_FORMAT_FRAME_SIZE // MUST be >= 320000/8/32000*1152 = 1440

#define MAX_BITRESERVOIR_BYTES      511
#define SHORT_BLOCK_TYPE            2
#define STOP_BLOCK_TYPE             3
#define MODE_MONO                   3
#define MODE_JOINT_STEREO           1
#define HDR_SIZE                    4
#define HDR_IS_MONO(h)              (((h[3]) & 0xC0) == 0xC0)
#define HDR_IS_MS_STEREO(h)         (((h[3]) & 0xE0) == 0x60)
#define HDR_IS_FREE_FORMAT(h)       (((h[2]) & 0xF0) == 0)
#define HDR_IS_CRC(h)               (!((h[1]) & 1))
#define HDR_TEST_PADDING(h)         ((h[2]) & 0x2)
#define HDR_TEST_MPEG1(h)           ((h[1]) & 0x8)
#define HDR_TEST_NOT_MPEG25(h)      ((h[1]) & 0x10)
#define HDR_TEST_I_STEREO(h)        ((h[3]) & 0x10)
#define HDR_TEST_MS_STEREO(h)       ((h[3]) & 0x20)
#define HDR_GET_STEREO_MODE(h)      (((h[3]) >> 6) & 3)
#define HDR_GET_STEREO_MODE_EXT(h)  (((h[3]) >> 4) & 3)
#define HDR_GET_LAYER(h)            (((h[1]) >> 1) & 3)
#define HDR_GET_BITRATE(h)          ((h[2]) >> 4)
#define HDR_GET_SAMPLE_RATE(h)      (((h[2]) >> 2) & 3)
#define HDR_GET_MY_SAMPLE_RATE(h)   (HDR_GET_SAMPLE_RATE(h) + (((h[1] >> 3) & 1) +  ((h[1] >> 4) & 1)) * 3)
#define HDR_IS_FRAME_576(h)         ((h[1] & 14) == 2)
#define HDR_IS_LAYER_1(h)           ((h[1] & 6) == 6)

#define BITS_DEQUANTIZER_OUT        -1
#define MAX_SCF                     (255 + BITS_DEQUANTIZER_OUT * 4 - 210)
#define MAX_SCFI                    ((MAX_SCF + 3) & ~3)

#define MIN(a,b)                    ((a) > (b) ? (b) : (a))
#define MAX(a,b)                    ((a) < (b) ? (b) : (a))

#if defined(_MSC_VER) || defined(__i386__) || defined(__x86_64__)
#   include <immintrin.h>
#   define HAVE_SSE 1
#   define HAVE_SIMD 1
#   define VSTORE _mm_storeu_ps
#   define VLD _mm_loadu_ps
#   define VSET _mm_set1_ps
#   define VADD _mm_add_ps
#   define VSUB _mm_sub_ps
#   define VMUL _mm_mul_ps
#   define VMAC(a, x, y) _mm_add_ps(a, _mm_mul_ps(x, y))
#   define VMSB(a, x, y) _mm_sub_ps(a, _mm_mul_ps(x, y))
#   define VMUL_S(x, s)  _mm_mul_ps(x, _mm_set1_ps(s))
#   define VREV(x) _mm_shuffle_ps(x, x, _MM_SHUFFLE(0, 1, 2, 3))
typedef __m128 f4;
#ifndef _MSC_VER
static __inline__ __attribute__((always_inline)) void __cpuid(int CPUInfo[], const int InfoType)
{
#if defined(__PIC__)
    __asm__ __volatile__(
#if defined(__x86_64__)
        "push %%rbx\n"
        "cpuid\n"
        "xchgl %%ebx, %1\n"
        "pop  %%rbx\n"
#else
        "xchgl %%ebx, %1\n"
        "cpuid\n"
        "xchgl %%ebx, %1\n"
#endif
        : "=a" (CPUInfo[0]), "=r" (CPUInfo[1]), "=c" (CPUInfo[2]), "=d" (CPUInfo[3])
        : "a" (InfoType));
#else
    __asm__ __volatile__(
        "cpuid"
        : "=a" (CPUInfo[0]), "=b" (CPUInfo[1]), "=c" (CPUInfo[2]), "=d" (CPUInfo[3])
        : "a" (InfoType));
#endif
}
#endif
static int have_simd()
{
    int CPUInfo[4];
    __cpuid(CPUInfo, 0);
    if (CPUInfo[0] > 0)
    {
        __cpuid(CPUInfo, 1);
        return (CPUInfo[3] & (1 << 26)); // SSE2
    }
    return 0;
}
#elif defined    __arm
#   include <arm_neon.h>
#   define HAVE_NEON 1
#   define HAVE_SIMD 1
#   define VSTORE vst1q_f32
#   define VLD vld1q_f32
#   define VSET vmovq_n_f32
#   define VADD vaddq_f32
#   define VSUB vsubq_f32
#   define VMUL vmulq_f32
#   define VMAC(a, x, y) vmlaq_f32(a, x, y)
#   define VMSB(a, x, y) vmlsq_f32(a, x, y)
#   define VMUL_S(x, s)  vmulq_f32(x, vmovq_n_f32(s))
#   define VREV(x) vrev64q_f32(x)
typedef float32x4_t f4;
static int have_simd()
{
    return 1;
}
#else
#   define HAVE_SIMD 0
#endif

typedef struct
{
    const uint8_t *buf;
    int pos;
    int limit;
} bs_t;

typedef struct
{
    uint8_t total_bands;
    uint8_t stereo_bands;
    uint8_t bitalloc[64];
    uint8_t scfcod[64];
    float scf[3*64];
} L12_scale_info;

typedef struct
{
    uint8_t tab_offset;
    uint8_t code_tab_width;
    uint8_t band_count;
} L12_subband_alloc_t;

typedef struct
{
    const uint8_t *sfbtab;
    uint16_t part_23_length;
    uint16_t big_values;
    uint16_t scalefac_compress;
    uint8_t global_gain;
    uint8_t block_type;
    uint8_t mixed_block_flag;
    uint8_t n_long_sfb;
    uint8_t n_short_sfb;
    uint8_t table_select[3];
    uint8_t region_count[3];
    uint8_t subblock_gain[3];
    uint8_t preflag;
    uint8_t scalefac_scale;
    uint8_t count1_table;
    uint8_t scfsi;
} L3_gr_info_t;

typedef struct
{
    bs_t bs;
    uint8_t maindata[MAX_BITRESERVOIR_BYTES + MAX_L3_FRAME_PAYLOAD_BYTES];
    L3_gr_info_t gr_info[4];
    float grbuf[2][576];
    float scf[40];
    uint8_t ist_pos[2][39];
    float syn[18 + 15][2*32];
} mp3dec_scratch_t;

static void bs_init(bs_t *bs, const uint8_t *data, int bytes)
{
    bs->buf   = data;
    bs->pos   = 0;
    bs->limit = bytes*8;
}

static uint32_t get_bits(bs_t *bs, int n)
{
    uint32_t next, cache = 0, s = bs->pos & 7;
    int shl = n + s;
    const uint8_t * p = bs->buf + (bs->pos >> 3);
    next = *p++ & (255 >> s);
    while ((shl -= 8) > 0)
    {
        cache |= next << shl;
        next = *p++;
    }
    bs->pos += n;
    return cache | (next >> -shl);
}

static int hdr_valid(const uint8_t *h)
{
    return h[0] == 0xff &&
        ((h[1] & 0xF0) == 0xf0 || (h[1] & 0xFE) == 0xe2) &&
        (HDR_GET_BITRATE(h) != 15) &&
        (HDR_GET_SAMPLE_RATE(h) != 3);
}

static int hdr_compare(const uint8_t *h1, const uint8_t *h2)
{
    return hdr_valid(h2) &&
        ((h1[1] ^ h2[1]) & 0xFE) == 0 &&
        ((h1[2] ^ h2[2]) & 0x0C) == 0 &&
        !(HDR_IS_FREE_FORMAT(h1) ^ HDR_IS_FREE_FORMAT(h2));
}

static unsigned hdr_bitrate_kbps(const uint8_t *h)
{
    static const uint8_t halfrate[2][3][15] = {
        { { 0,4,8,12,16,20,24,28,32,40,48,56,64,72,80 }, { 0,4,8,12,16,20,24,28,32,40,48,56,64,72,80 }, { 0,16,24,28,32,40,48,56,64,72,80,88,96,112,128 } },
        { { 0,16,20,24,28,32,40,48,56,64,80,96,112,128,160 }, { 0,16,24,28,32,40,48,56,64,80,96,112,128,160,192 }, { 0,16,32,48,64,80,96,112,128,144,160,176,192,208,224 } },
    };
    return 2*halfrate[!!HDR_TEST_MPEG1(h)][HDR_GET_LAYER(h) - 1][HDR_GET_BITRATE(h)];
}

static unsigned hdr_sample_rate_hz(const uint8_t *h)
{
    static const unsigned g_hz[3] = { 44100, 48000, 32000 };
    return g_hz[HDR_GET_SAMPLE_RATE(h)] >> !HDR_TEST_MPEG1(h) >> !HDR_TEST_NOT_MPEG25(h);
}

static unsigned hdr_frame_samples(const uint8_t *h)
{
    return HDR_IS_LAYER_1(h) ? 384 : (1152 >> HDR_IS_FRAME_576(h));
}

static int hdr_frame_bytes(const uint8_t *h, int free_format_size)
{
    int frame_bytes = hdr_frame_samples(h) * hdr_bitrate_kbps(h) * 125 / hdr_sample_rate_hz(h);
    if (HDR_IS_LAYER_1(h))
    {
        frame_bytes &= ~3; //Slot align
    }
    return frame_bytes ? frame_bytes : free_format_size;
}

static int hdr_padding(const uint8_t *h)
{
    return HDR_TEST_PADDING(h) ? (HDR_IS_LAYER_1(h) ? 4 : 1) : 0;
}

static const L12_subband_alloc_t * L12_subband_alloc_table(const uint8_t *hdr, L12_scale_info *sci)
{
    const L12_subband_alloc_t *alloc;
    int mode = HDR_GET_STEREO_MODE(hdr);
    int nbands, stereo_bands = (mode == MODE_MONO) ? 0 : (mode == MODE_JOINT_STEREO) ? (HDR_GET_STEREO_MODE_EXT(hdr) << 2) + 4 : 32;

    if (HDR_IS_LAYER_1(hdr))
    {
        static const L12_subband_alloc_t g_alloc_L1[] = { { 76, 4, 32 } };
        alloc = g_alloc_L1;
        nbands = 32;
    } else if (!HDR_TEST_MPEG1(hdr))
    {
        static const L12_subband_alloc_t g_alloc_L2M2[] = { { 60, 4, 4 }, { 44, 3, 7 }, { 44, 2, 19 } };
        alloc = g_alloc_L2M2;
        nbands = 30;
    } else
    {
        static const L12_subband_alloc_t g_alloc_L2M1[] = { { 0, 4, 3 }, { 16, 4, 8 }, { 32, 3, 12 }, { 40, 2, 7 } };
        int sample_rate_idx = HDR_GET_SAMPLE_RATE(hdr);
        unsigned kbps = hdr_bitrate_kbps(hdr) >> (mode != MODE_MONO);
        if (!kbps) // free-format
        {
            kbps = 192;
        }

        alloc = g_alloc_L2M1;
        nbands = 27;
        if (kbps < 56)
        {
            static const L12_subband_alloc_t g_alloc_L2M1_lowrate[] = { { 44, 4, 2 }, { 44, 3, 10 } };
            alloc = g_alloc_L2M1_lowrate;
            nbands = sample_rate_idx == 2 ? 12 : 8;
        } else if (kbps >= 96 && sample_rate_idx != 1)
        {
            nbands = 30;
        }
    }

    sci->total_bands = (uint8_t)nbands;
    sci->stereo_bands = (uint8_t)MIN(stereo_bands, nbands);

    return alloc;
}

static void L12_read_scalefactors(bs_t *bs, uint8_t *pba, uint8_t *scfcod, int bands, float *scf)
{
    static const float g_deq_L12[18*3] = {
#define DQ(x) 9.53674316e-07f/x, 7.56931807e-07f/x, 6.00777173e-07f/x
        DQ(3),DQ(7),DQ(15),DQ(31),DQ(63),DQ(127),DQ(255),DQ(511),DQ(1023),DQ(2047),DQ(4095),DQ(8191),DQ(16383),DQ(32767),DQ(65535),DQ(3),DQ(5),DQ(9)
    };
    int i, m;
    for (i = 0; i < bands; i++)
    {
        float s = 0;
        int ba = *pba++;
        int mask = ba ? 4 + ((19 >> scfcod[i]) & 3) : 0;
        for (m = 4; m; m >>= 1)
        {
            if (mask & m)
            {
                int b = get_bits(bs, 6);
                s = g_deq_L12[ba*3 - 6 + b % 3] * (1 << 21 >> b/3);
            }
            *scf++ = s;
        }
    }
}

static void L12_read_scale_info(const uint8_t *hdr, bs_t *bs, L12_scale_info *sci)
{
    static const uint8_t g_bitalloc_code_tab[] = {
        0,17, 3, 4, 5,6,7, 8,9,10,11,12,13,14,15,16,
        0,17,18, 3,19,4,5, 6,7, 8, 9,10,11,12,13,16,
        0,17,18, 3,19,4,5,16,
        0,17,18,16,
        0,17,18,19, 4,5,6, 7,8, 9,10,11,12,13,14,15,
        0,17,18, 3,19,4,5, 6,7, 8, 9,10,11,12,13,14,
        0, 2, 3, 4, 5,6,7, 8,9,10,11,12,13,14,15,16
    };
    const L12_subband_alloc_t * subband_alloc = L12_subband_alloc_table(hdr, sci);

    int i, k = 0, ba_bits = 0;
    const uint8_t *ba_code_tab = g_bitalloc_code_tab;

    for (i = 0; i < sci->total_bands; i++)
    {
        uint8_t ba;
        if (i == k)
        {
            k += subband_alloc->band_count;
            ba_bits = subband_alloc->code_tab_width;
            ba_code_tab = g_bitalloc_code_tab + subband_alloc->tab_offset;
            subband_alloc++;
        }
        ba = ba_code_tab[get_bits(bs, ba_bits)];
        sci->bitalloc[2*i] = ba;
        if (i < sci->stereo_bands)
        {
            ba = ba_code_tab[get_bits(bs, ba_bits)];
        }
        sci->bitalloc[2*i+1] = sci->stereo_bands ? ba : 0;
    }

    for (i = 0; i < 2 * sci->total_bands; i++)
    {
        sci->scfcod[i] = sci->bitalloc[i] ? HDR_IS_LAYER_1(hdr) ? 2 : get_bits(bs, 2) : 6;
    }

    L12_read_scalefactors(bs, sci->bitalloc, sci->scfcod, sci->total_bands * 2, sci->scf);

    for (i = sci->stereo_bands; i < sci->total_bands; i++)
    {
        sci->bitalloc[2*i + 1] = 0;
    }
}

static int L12_dequantize_granule(float *grbuf, bs_t *bs, L12_scale_info *sci, int group_size)
{
    int i, j, k, choff = 576;
    for (j = 0; j < 4; j++)
    {
        float *dst = grbuf + group_size*j;
        for (i = 0; i < 2*sci->total_bands; i++)
        {
            int ba = sci->bitalloc[i];
            if (ba != 0)
            {
                if (ba < 17)
                {
                    int half = (1 << (ba - 1)) - 1;
                    for (k = 0; k < group_size; k++)
                    {
                        dst[k] = (float)((int)get_bits(bs, ba) - half);
                    }
                } else
                {
                    unsigned mod = (2 << (ba - 17)) + 1;    // 3, 5, 9
                    unsigned code = get_bits(bs, mod + 2 - (mod >> 3));  // 5, 7, 10
                    for (k = 0; k < group_size; k++, code /= mod)
                    {
                        dst[k] = (float)((int)(code % mod - mod/2));
                    }
                }
            }
            dst += choff;
            choff = 18 - choff;
        }
    }
    return group_size*4;
}

static void L12_apply_scf_384(L12_scale_info *sci, const float *scf, float *dst)
{
    int i, k;
    memcpy(dst + 576 + sci->stereo_bands*18, dst + sci->stereo_bands*18, (sci->total_bands - sci->stereo_bands)*18*sizeof(float));
    for (i = 0; i < sci->total_bands; i++, dst += 18, scf += 6)
    {
        for (k = 0; k < 12; k++)
        {
            dst[k + 0]   *= scf[0];
            dst[k + 576] *= scf[3];
        }
    }
}

static int L3_read_side_info(bs_t *bs, L3_gr_info_t *gr, const uint8_t *hdr)
{
    static const uint8_t g_scf_long[9][23] = {
        { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
        { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
        { 12,12,12,12,12,12,16,20,24,28,32,40,48,56,64,76,90,2,2,2,2,2,0 },
        { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
        { 6,6,6,6,6,6,8,10,12,14,16,18,22,26,32,38,46,54,62,70,76,36,0 },
        { 6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54,0 },
        { 4,4,4,4,4,4,6,6,8,8,10,12,16,20,24,28,34,42,50,54,76,158,0 },
        { 4,4,4,4,4,4,6,6,6,8,10,12,16,18,22,28,34,40,46,54,54,192,0 },
        { 4,4,4,4,4,4,6,6,8,10,12,16,20,24,30,38,46,56,68,84,102,26,0 }
    };
    static const uint8_t g_scf_short[9][40] = {
        { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 8,8,8,8,8,8,8,8,8,12,12,12,16,16,16,20,20,20,24,24,24,28,28,28,36,36,36,2,2,2,2,2,2,2,2,2,26,26,26,0 },
        { 4,4,4,4,4,4,4,4,4,6,6,6,6,6,6,8,8,8,10,10,10,14,14,14,18,18,18,26,26,26,32,32,32,42,42,42,18,18,18,0 },
        { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,32,32,32,44,44,44,12,12,12,0 },
        { 4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,22,22,22,30,30,30,56,56,56,0 },
        { 4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,6,6,6,10,10,10,12,12,12,14,14,14,16,16,16,20,20,20,26,26,26,66,66,66,0 },
        { 4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,8,8,8,12,12,12,16,16,16,20,20,20,26,26,26,34,34,34,42,42,42,12,12,12,0 }
    };
    static const uint8_t g_scf_mixed[9][40] = {
        { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 12,12,12,4,4,4,8,8,8,12,12,12,16,16,16,20,20,20,24,24,24,28,28,28,36,36,36,2,2,2,2,2,2,2,2,2,26,26,26,0 },
        { 6,6,6,6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,14,14,14,18,18,18,26,26,26,32,32,32,42,42,42,18,18,18,0 },
        { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,32,32,32,44,44,44,12,12,12,0 },
        { 6,6,6,6,6,6,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,24,24,24,30,30,30,40,40,40,18,18,18,0 },
        { 4,4,4,4,4,4,6,6,4,4,4,6,6,6,8,8,8,10,10,10,12,12,12,14,14,14,18,18,18,22,22,22,30,30,30,56,56,56,0 },
        { 4,4,4,4,4,4,6,6,4,4,4,6,6,6,6,6,6,10,10,10,12,12,12,14,14,14,16,16,16,20,20,20,26,26,26,66,66,66,0 },
        { 4,4,4,4,4,4,6,6,4,4,4,6,6,6,8,8,8,12,12,12,16,16,16,20,20,20,26,26,26,34,34,34,42,42,42,12,12,12,0 }
    };

    unsigned tables, scfsi = 0;
    int main_data_begin, part_23_sum = 0;
    int sr_idx = HDR_GET_MY_SAMPLE_RATE(hdr);
    int gr_count = HDR_IS_MONO(hdr) ? 1 : 2;

    if (HDR_TEST_MPEG1(hdr))
    {
        gr_count *= 2;
        main_data_begin = get_bits(bs, 9);
        scfsi = get_bits(bs, 7 + gr_count);
    } else
    {
        main_data_begin = get_bits(bs, 8 + gr_count) >> gr_count;
    }

    do
    {
        if (HDR_IS_MONO(hdr))
        {
            scfsi <<= 4;
        }
        gr->part_23_length = (uint16_t)get_bits(bs, 12);
        part_23_sum += gr->part_23_length;
        gr->big_values = (uint16_t)get_bits(bs,  9);
        if (gr->big_values > 288)
        {
            return -1;
        }
        gr->global_gain = (uint8_t)get_bits(bs, 8);
        gr->scalefac_compress = (uint16_t)get_bits(bs, HDR_TEST_MPEG1(hdr) ? 4 : 9);
        gr->sfbtab = g_scf_long[sr_idx];
        gr->n_long_sfb  = 22;
        gr->n_short_sfb = 0;
        if (get_bits(bs, 1))
        {
            gr->block_type = (uint8_t)get_bits(bs, 2);
            if (!gr->block_type)
            {
                return -1;
            }
            gr->mixed_block_flag = (uint8_t)get_bits(bs, 1);
            gr->region_count[0] = 7;
            gr->region_count[1] = 255;
            if (gr->block_type == SHORT_BLOCK_TYPE)
            {
                scfsi &= 0x0F0F;
                if (!gr->mixed_block_flag)
                {
                    gr->region_count[0] = 8;
                    gr->sfbtab = g_scf_short[sr_idx];
                    gr->n_long_sfb = 0;
                    gr->n_short_sfb = 39;
                } else
                {
                    gr->sfbtab = g_scf_mixed[sr_idx];
                    gr->n_long_sfb = HDR_TEST_MPEG1(hdr) ? 8 : 6;
                    gr->n_short_sfb = 30;
                }
            }
            tables = get_bits(bs, 10);
            tables <<= 5;
            gr->subblock_gain[0] = (uint8_t)get_bits(bs, 3);
            gr->subblock_gain[1] = (uint8_t)get_bits(bs, 3);
            gr->subblock_gain[2] = (uint8_t)get_bits(bs, 3);
        } else
        {
            gr->block_type = 0;
            gr->mixed_block_flag = 0;
            tables = get_bits(bs, 15);
            gr->region_count[0] = (uint8_t)get_bits(bs, 4);
            gr->region_count[1] = (uint8_t)get_bits(bs, 3);
            gr->region_count[2] = 255;
        }
        gr->table_select[0] = (uint8_t)(tables >> 10);
        gr->table_select[1] = (uint8_t)((tables >> 5) & 31);
        gr->table_select[2] = (uint8_t)((tables) & 31);
        gr->preflag = HDR_TEST_MPEG1(hdr) ? get_bits(bs, 1) : (gr->scalefac_compress >= 500);
        gr->scalefac_scale = (uint8_t)get_bits(bs, 1);
        gr->count1_table = (uint8_t)get_bits(bs, 1);
        gr->scfsi = (uint8_t)((scfsi >> 12) & 15);
        scfsi <<= 4;
        gr++;
    } while(--gr_count);

    if (part_23_sum + bs->pos > bs->limit + main_data_begin*8)
    {
        return -1;
    }

    return main_data_begin;
}

static void L3_read_scalefactors(uint8_t *scf, uint8_t *ist_pos, const uint8_t *scf_size, const uint8_t *scf_count, bs_t *bitbuf, int scfsi)
{
    int i, k;
    for (i = 0; i < 4 && scf_count[i]; i++, scfsi <<= 1)
    {
        int cnt = scf_count[i];
        if (scfsi & 8)
        {
            memcpy(scf, ist_pos, cnt);
        } else
        {
            int bits = scf_size[i];
            if (!bits)
            {
                memset(scf, 0, cnt);
                memset(ist_pos, 0, cnt);
            } else
            {
                int max_scf = (scfsi < 0) ? (1 << bits) - 1 : -1;
                for (k = 0; k < cnt; k++)
                {
                    int s = get_bits(bitbuf, bits);
                    ist_pos[k] = (s == max_scf ? -1 : s);
                    scf[k] = s;
                }
            }
        }
        ist_pos += cnt;
        scf += cnt;
    }
    scf[0] = scf[1] = scf[2] = 0;
}

static float L3_ldexp_q2(int e)
{
    static const float g_expfrac[4] = { 9.31322575e-10f,7.83145814e-10f,6.58544508e-10f,5.53767716e-10f };
    return g_expfrac[e & 3]*(1 << 30 >> (e >> 2));
}

static void L3_decode_scalefactors(const uint8_t *hdr, uint8_t *ist_pos, bs_t *bs, const L3_gr_info_t *gr, float *scf, int ch)
{
    static const uint8_t g_scf_partitions[3][28] = {
        { 6,5,5, 5,6,5,5,5,6,5, 7,3,11,10,0,0, 7, 7, 7,0, 6, 6,6,3, 8, 8,5,0 },
        { 8,9,6,12,6,9,9,9,6,9,12,6,15,18,0,0, 6,15,12,0, 6,12,9,6, 6,18,9,0 },
        { 9,9,6,12,9,9,9,9,9,9,12,6,18,18,0,0,12,12,12,0,12, 9,9,6,15,12,9,0 }
    };
    const uint8_t *scf_partition = g_scf_partitions[!!gr->n_short_sfb + !gr->n_long_sfb];
    uint8_t scf_size[4], iscf[40];
    int i, scf_shift = gr->scalefac_scale + 1, gain_exp, scfsi = gr->scfsi;
    float gain;

    if (HDR_TEST_MPEG1(hdr))
    {
        static const uint8_t g_scfc_decode[16] = { 0,1,2,3, 12,5,6,7, 9,10,11,13, 14,15,18,19 };
        int part = g_scfc_decode[gr->scalefac_compress];
        scf_size[1] = scf_size[0] = (uint8_t)(part >> 2);
        scf_size[3] = scf_size[2] = (uint8_t)(part & 3);
    } else
    {
        static const uint8_t g_mod[6*4] = { 5,5,4,4,5,5,4,1,4,3,1,1,5,6,6,1,4,4,4,1,4,3,1,1 };
        int k, modprod, sfc, ist = HDR_TEST_I_STEREO(hdr) && ch;
        sfc = gr->scalefac_compress >> ist;
        for (k = ist*3*4; sfc >= 0; sfc -= modprod, k += 4)
        {
            for (modprod = 1, i = 3; i >= 0; i--)
            {
                scf_size[i] = (uint8_t)(sfc / modprod % g_mod[k + i]);
                modprod *= g_mod[k + i];
            }
        }
        scf_partition += k;
        scfsi = -16;
    }
    L3_read_scalefactors(iscf, ist_pos, scf_size, scf_partition, bs, scfsi);

    if (gr->n_short_sfb)
    {
        int sh = 3 - scf_shift;
        for (i = 0; i < gr->n_short_sfb; i += 3)
        {
            iscf[gr->n_long_sfb + i + 0] += gr->subblock_gain[0] << sh;
            iscf[gr->n_long_sfb + i + 1] += gr->subblock_gain[1] << sh;
            iscf[gr->n_long_sfb + i + 2] += gr->subblock_gain[2] << sh;
        }
    }
    else if (gr->preflag)
    {
        static const uint8_t g_preamp[10] = { 1,1,1,1,2,2,3,3,3,2 };
        for (i = 0; i < 10; i++)
        {
            iscf[11 + i] += g_preamp[i];
        }
    }

    gain_exp = gr->global_gain + BITS_DEQUANTIZER_OUT*4 - 210 - (HDR_IS_MS_STEREO(hdr) ? 2 : 0);
    gain = 1 << (MAX_SCFI/4);

    while (gain_exp < MAX_SCFI)
    {
        int dexp = MIN(30*4, MAX_SCFI - gain_exp);
        gain *= L3_ldexp_q2(dexp);
        gain_exp += dexp;
    }

    for (i = 0; i < (int)(gr->n_long_sfb + gr->n_short_sfb); i++)
    {
        scf[i] = gain*L3_ldexp_q2(iscf[i] << scf_shift);
    }
}


static float L3_pow_43(int x)
{
    static const float g_pow43[129] = {
        0,1,2.519842f,4.326749f,6.349604f,8.549880f,10.902724f,13.390518f,16.000000f,18.720754f,21.544347f,24.463781f,27.473142f,30.567351f,33.741992f,36.993181f,40.317474f,43.711787f,47.173345f,50.699631f,54.288352f,57.937408f,61.644865f,65.408941f,69.227979f,73.100443f,77.024898f,81.000000f,85.024491f,89.097188f,93.216975f,97.382800f,101.593667f,105.848633f,110.146801f,114.487321f,118.869381f,123.292209f,127.755065f,132.257246f,136.798076f,141.376907f,145.993119f,150.646117f,155.335327f,160.060199f,164.820202f,169.614826f,174.443577f,179.305980f,184.201575f,189.129918f,194.090580f,199.083145f,204.107210f,209.162385f,214.248292f,219.364564f,224.510845f,229.686789f,234.892058f,240.126328f,245.389280f,250.680604f,256.000000f,261.347174f,266.721841f,272.123723f,277.552547f,283.008049f,288.489971f,293.998060f,299.532071f,305.091761f,310.676898f,316.287249f,321.922592f,327.582707f,333.267377f,338.976394f,344.709550f,350.466646f,356.247482f,362.051866f,367.879608f,373.730522f,379.604427f,385.501143f,391.420496f,397.362314f,403.326427f,409.312672f,415.320884f,421.350905f,427.402579f,433.475750f,439.570269f,445.685987f,451.822757f,457.980436f,464.158883f,470.357960f,476.577530f,482.817459f,489.077615f,495.357868f,501.658090f,507.978156f,514.317941f,520.677324f,527.056184f,533.454404f,539.871867f,546.308458f,552.764065f,559.238575f,565.731879f,572.243870f,578.774440f,585.323483f,591.890898f,598.476581f,605.080431f,611.702349f,618.342238f,625.000000f,631.675540f,638.368763f,645.079578f
    };
    float frac;
    int sign, mult = 256;

    if (x < 129)
    {
        return g_pow43[x];
    }

    if (x < 1024)
    {
        mult = 16;
        x <<= 3;
    }

    sign = 2*x & 64;
    frac = (float)((x & 63) - sign) / ((x & ~63) + sign);
    return g_pow43[(x + sign) >> 6] * (1.f + frac * ((4.f/3) + frac * (2.f/9))) * mult;
}

static void L3_huffman(float *dst, bs_t *bs, const L3_gr_info_t *gr_info, const float *scf, int layer3gr_limit)
{
    static const float g_pow43_signed[32] = { 0,0,1,-1,2.519842f,-2.519842f,4.326749f,-4.326749f,6.349604f,-6.349604f,8.549880f,-8.549880f,10.902724f,-10.902724f,13.390518f,-13.390518f,16.000000f,-16.000000f,18.720754f,-18.720754f,21.544347f,-21.544347f,24.463781f,-24.463781f,27.473142f,-27.473142f,30.567351f,-30.567351f,33.741992f,-33.741992f,36.993181f,-36.993181f };
    static const int16_t tab0[32] = { 0, };
    static const int16_t tab1[] = { 785,785,785,785,784,784,784,784,513,513,513,513,513,513,513,513,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256 };
    static const int16_t tab2[] = { -255,1313,1298,1282,785,785,785,785,784,784,784,784,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,290,288 };
    static const int16_t tab3[] = { -255,1313,1298,1282,769,769,769,769,529,529,529,529,529,529,529,529,528,528,528,528,528,528,528,528,512,512,512,512,512,512,512,512,290,288 };
    static const int16_t tab5[] = { -253,-318,-351,-367,785,785,785,785,784,784,784,784,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,819,818,547,547,275,275,275,275,561,560,515,546,289,274,288,258 };
    static const int16_t tab6[] = { -254,-287,1329,1299,1314,1312,1057,1057,1042,1042,1026,1026,784,784,784,784,529,529,529,529,529,529,529,529,769,769,769,769,768,768,768,768,563,560,306,306,291,259 };
    static const int16_t tab7[] = { -252,-413,-477,-542,1298,-575,1041,1041,784,784,784,784,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,-383,-399,1107,1092,1106,1061,849,849,789,789,1104,1091,773,773,1076,1075,341,340,325,309,834,804,577,577,532,532,516,516,832,818,803,816,561,561,531,531,515,546,289,289,288,258 };
    static const int16_t tab8[] = { -252,-429,-493,-559,1057,1057,1042,1042,529,529,529,529,529,529,529,529,784,784,784,784,769,769,769,769,512,512,512,512,512,512,512,512,-382,1077,-415,1106,1061,1104,849,849,789,789,1091,1076,1029,1075,834,834,597,581,340,340,339,324,804,833,532,532,832,772,818,803,817,787,816,771,290,290,290,290,288,258 };
    static const int16_t tab9[] = { -253,-349,-414,-447,-463,1329,1299,-479,1314,1312,1057,1057,1042,1042,1026,1026,785,785,785,785,784,784,784,784,769,769,769,769,768,768,768,768,-319,851,821,-335,836,850,805,849,341,340,325,336,533,533,579,579,564,564,773,832,578,548,563,516,321,276,306,291,304,259 };
    static const int16_t tab10[] = { -251,-572,-733,-830,-863,-879,1041,1041,784,784,784,784,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,-511,-527,-543,1396,1351,1381,1366,1395,1335,1380,-559,1334,1138,1138,1063,1063,1350,1392,1031,1031,1062,1062,1364,1363,1120,1120,1333,1348,881,881,881,881,375,374,359,373,343,358,341,325,791,791,1123,1122,-703,1105,1045,-719,865,865,790,790,774,774,1104,1029,338,293,323,308,-799,-815,833,788,772,818,803,816,322,292,307,320,561,531,515,546,289,274,288,258 };
    static const int16_t tab11[] = { -251,-525,-605,-685,-765,-831,-846,1298,1057,1057,1312,1282,785,785,785,785,784,784,784,784,769,769,769,769,512,512,512,512,512,512,512,512,1399,1398,1383,1367,1382,1396,1351,-511,1381,1366,1139,1139,1079,1079,1124,1124,1364,1349,1363,1333,882,882,882,882,807,807,807,807,1094,1094,1136,1136,373,341,535,535,881,775,867,822,774,-591,324,338,-671,849,550,550,866,864,609,609,293,336,534,534,789,835,773,-751,834,804,308,307,833,788,832,772,562,562,547,547,305,275,560,515,290,290 };
    static const int16_t tab12[] = { -252,-397,-477,-557,-622,-653,-719,-735,-750,1329,1299,1314,1057,1057,1042,1042,1312,1282,1024,1024,785,785,785,785,784,784,784,784,769,769,769,769,-383,1127,1141,1111,1126,1140,1095,1110,869,869,883,883,1079,1109,882,882,375,374,807,868,838,881,791,-463,867,822,368,263,852,837,836,-543,610,610,550,550,352,336,534,534,865,774,851,821,850,805,593,533,579,564,773,832,578,578,548,548,577,577,307,276,306,291,516,560,259,259 };
    static const int16_t tab13[] = { -250,-2107,-2507,-2764,-2909,-2974,-3007,-3023,1041,1041,1040,1040,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,-767,-1052,-1213,-1277,-1358,-1405,-1469,-1535,-1550,-1582,-1614,-1647,-1662,-1694,-1726,-1759,-1774,-1807,-1822,-1854,-1886,1565,-1919,-1935,-1951,-1967,1731,1730,1580,1717,-1983,1729,1564,-1999,1548,-2015,-2031,1715,1595,-2047,1714,-2063,1610,-2079,1609,-2095,1323,1323,1457,1457,1307,1307,1712,1547,1641,1700,1699,1594,1685,1625,1442,1442,1322,1322,-780,-973,-910,1279,1278,1277,1262,1276,1261,1275,1215,1260,1229,-959,974,974,989,989,-943,735,478,478,495,463,506,414,-1039,1003,958,1017,927,942,987,957,431,476,1272,1167,1228,-1183,1256,-1199,895,895,941,941,1242,1227,1212,1135,1014,1014,490,489,503,487,910,1013,985,925,863,894,970,955,1012,847,-1343,831,755,755,984,909,428,366,754,559,-1391,752,486,457,924,997,698,698,983,893,740,740,908,877,739,739,667,667,953,938,497,287,271,271,683,606,590,712,726,574,302,302,738,736,481,286,526,725,605,711,636,724,696,651,589,681,666,710,364,467,573,695,466,466,301,465,379,379,709,604,665,679,316,316,634,633,436,436,464,269,424,394,452,332,438,363,347,408,393,448,331,422,362,407,392,421,346,406,391,376,375,359,1441,1306,-2367,1290,-2383,1337,-2399,-2415,1426,1321,-2431,1411,1336,-2447,-2463,-2479,1169,1169,1049,1049,1424,1289,1412,1352,1319,-2495,1154,1154,1064,1064,1153,1153,416,390,360,404,403,389,344,374,373,343,358,372,327,357,342,311,356,326,1395,1394,1137,1137,1047,1047,1365,1392,1287,1379,1334,1364,1349,1378,1318,1363,792,792,792,792,1152,1152,1032,1032,1121,1121,1046,1046,1120,1120,1030,1030,-2895,1106,1061,1104,849,849,789,789,1091,1076,1029,1090,1060,1075,833,833,309,324,532,532,832,772,818,803,561,561,531,560,515,546,289,274,288,258 };
    static const int16_t tab15[] = { -250,-1179,-1579,-1836,-1996,-2124,-2253,-2333,-2413,-2477,-2542,-2574,-2607,-2622,-2655,1314,1313,1298,1312,1282,785,785,785,785,1040,1040,1025,1025,768,768,768,768,-766,-798,-830,-862,-895,-911,-927,-943,-959,-975,-991,-1007,-1023,-1039,-1055,-1070,1724,1647,-1103,-1119,1631,1767,1662,1738,1708,1723,-1135,1780,1615,1779,1599,1677,1646,1778,1583,-1151,1777,1567,1737,1692,1765,1722,1707,1630,1751,1661,1764,1614,1736,1676,1763,1750,1645,1598,1721,1691,1762,1706,1582,1761,1566,-1167,1749,1629,767,766,751,765,494,494,735,764,719,749,734,763,447,447,748,718,477,506,431,491,446,476,461,505,415,430,475,445,504,399,460,489,414,503,383,474,429,459,502,502,746,752,488,398,501,473,413,472,486,271,480,270,-1439,-1455,1357,-1471,-1487,-1503,1341,1325,-1519,1489,1463,1403,1309,-1535,1372,1448,1418,1476,1356,1462,1387,-1551,1475,1340,1447,1402,1386,-1567,1068,1068,1474,1461,455,380,468,440,395,425,410,454,364,467,466,464,453,269,409,448,268,432,1371,1473,1432,1417,1308,1460,1355,1446,1459,1431,1083,1083,1401,1416,1458,1445,1067,1067,1370,1457,1051,1051,1291,1430,1385,1444,1354,1415,1400,1443,1082,1082,1173,1113,1186,1066,1185,1050,-1967,1158,1128,1172,1097,1171,1081,-1983,1157,1112,416,266,375,400,1170,1142,1127,1065,793,793,1169,1033,1156,1096,1141,1111,1155,1080,1126,1140,898,898,808,808,897,897,792,792,1095,1152,1032,1125,1110,1139,1079,1124,882,807,838,881,853,791,-2319,867,368,263,822,852,837,866,806,865,-2399,851,352,262,534,534,821,836,594,594,549,549,593,593,533,533,848,773,579,579,564,578,548,563,276,276,577,576,306,291,516,560,305,305,275,259 };
    static const int16_t tab16[] = { -251,-892,-2058,-2620,-2828,-2957,-3023,-3039,1041,1041,1040,1040,769,769,769,769,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,256,-511,-527,-543,-559,1530,-575,-591,1528,1527,1407,1526,1391,1023,1023,1023,1023,1525,1375,1268,1268,1103,1103,1087,1087,1039,1039,1523,-604,815,815,815,815,510,495,509,479,508,463,507,447,431,505,415,399,-734,-782,1262,-815,1259,1244,-831,1258,1228,-847,-863,1196,-879,1253,987,987,748,-767,493,493,462,477,414,414,686,669,478,446,461,445,474,429,487,458,412,471,1266,1264,1009,1009,799,799,-1019,-1276,-1452,-1581,-1677,-1757,-1821,-1886,-1933,-1997,1257,1257,1483,1468,1512,1422,1497,1406,1467,1496,1421,1510,1134,1134,1225,1225,1466,1451,1374,1405,1252,1252,1358,1480,1164,1164,1251,1251,1238,1238,1389,1465,-1407,1054,1101,-1423,1207,-1439,830,830,1248,1038,1237,1117,1223,1148,1236,1208,411,426,395,410,379,269,1193,1222,1132,1235,1221,1116,976,976,1192,1162,1177,1220,1131,1191,963,963,-1647,961,780,-1663,558,558,994,993,437,408,393,407,829,978,813,797,947,-1743,721,721,377,392,844,950,828,890,706,706,812,859,796,960,948,843,934,874,571,571,-1919,690,555,689,421,346,539,539,944,779,918,873,932,842,903,888,570,570,931,917,674,674,-2575,1562,-2591,1609,-2607,1654,1322,1322,1441,1441,1696,1546,1683,1593,1669,1624,1426,1426,1321,1321,1639,1680,1425,1425,1305,1305,1545,1668,1608,1623,1667,1592,1638,1666,1320,1320,1652,1607,1409,1409,1304,1304,1288,1288,1664,1637,1395,1395,1335,1335,1622,1636,1394,1394,1319,1319,1606,1621,1392,1392,1137,1137,1137,1137,345,390,360,375,404,373,1047,-2751,-2767,-2783,1062,1121,1046,-2799,1077,-2815,1106,1061,789,789,1105,1104,263,355,310,340,325,354,352,262,339,324,1091,1076,1029,1090,1060,1075,833,833,788,788,1088,1028,818,818,803,803,561,561,531,531,816,771,546,546,289,274,288,258 };
    static const int16_t tab24[] = { -253,-317,-381,-446,-478,-509,1279,1279,-811,-1179,-1451,-1756,-1900,-2028,-2189,-2253,-2333,-2414,-2445,-2511,-2526,1313,1298,-2559,1041,1041,1040,1040,1025,1025,1024,1024,1022,1007,1021,991,1020,975,1019,959,687,687,1018,1017,671,671,655,655,1016,1015,639,639,758,758,623,623,757,607,756,591,755,575,754,559,543,543,1009,783,-575,-621,-685,-749,496,-590,750,749,734,748,974,989,1003,958,988,973,1002,942,987,957,972,1001,926,986,941,971,956,1000,910,985,925,999,894,970,-1071,-1087,-1102,1390,-1135,1436,1509,1451,1374,-1151,1405,1358,1480,1420,-1167,1507,1494,1389,1342,1465,1435,1450,1326,1505,1310,1493,1373,1479,1404,1492,1464,1419,428,443,472,397,736,526,464,464,486,457,442,471,484,482,1357,1449,1434,1478,1388,1491,1341,1490,1325,1489,1463,1403,1309,1477,1372,1448,1418,1433,1476,1356,1462,1387,-1439,1475,1340,1447,1402,1474,1324,1461,1371,1473,269,448,1432,1417,1308,1460,-1711,1459,-1727,1441,1099,1099,1446,1386,1431,1401,-1743,1289,1083,1083,1160,1160,1458,1445,1067,1067,1370,1457,1307,1430,1129,1129,1098,1098,268,432,267,416,266,400,-1887,1144,1187,1082,1173,1113,1186,1066,1050,1158,1128,1143,1172,1097,1171,1081,420,391,1157,1112,1170,1142,1127,1065,1169,1049,1156,1096,1141,1111,1155,1080,1126,1154,1064,1153,1140,1095,1048,-2159,1125,1110,1137,-2175,823,823,1139,1138,807,807,384,264,368,263,868,838,853,791,867,822,852,837,866,806,865,790,-2319,851,821,836,352,262,850,805,849,-2399,533,533,835,820,336,261,578,548,563,577,532,532,832,772,562,562,547,547,305,275,560,515,290,290,288,258 };
    static const uint8_t tab32[] = { 130,162,193,209,44,28,76,140,9,9,9,9,9,9,9,9,190,254,222,238,126,94,157,157,109,61,173,205};
    static const uint8_t tab33[] = { 252,236,220,204,188,172,156,140,124,108,92,76,60,44,28,12 };
    static const int16_t * const tabindex[2*16] = { tab0,tab1,tab2,tab3,tab0,tab5,tab6,tab7,tab8,tab9,tab10,tab11,tab12,tab13,tab0,tab15,tab16,tab16,tab16,tab16,tab16,tab16,tab16,tab16,tab24,tab24,tab24,tab24,tab24,tab24,tab24,tab24 };
    static const uint8_t g_linbits[] =  { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,2,3,4,6,8,10,13,4,5,6,7,8,9,11,13 };

#define PEEK_BITS(n)    (bs_cache >> (32 - n))
#define FLUSH_BITS(n)   {bs_cache <<= (n); bs_sh += (n);}
#define CHECK_BITS      while (bs_sh >= 0) { bs_cache |= (uint32_t)*bs_next_ptr++ << bs_sh; bs_sh -= 8; }
#define BSPOS           ((bs_next_ptr - bs->buf)*8 - 24 + bs_sh)

    float one;
    int ireg = 0, big_val_cnt = gr_info->big_values;
    const uint8_t *sfb = gr_info->sfbtab;
    const uint8_t *bs_next_ptr = bs->buf + bs->pos/8;
    uint32_t bs_cache = (((bs_next_ptr[0]*256 + bs_next_ptr[1])*256 + bs_next_ptr[2])*256 + bs_next_ptr[3]) << (bs->pos & 7);
    int pairs_to_decode, np, bs_sh = (bs->pos & 7) - 8;
    bs_next_ptr += 4;

    while (big_val_cnt > 0)
    {
        int tab_num = gr_info->table_select[ireg];
        int sfb_cnt = gr_info->region_count[ireg++];
        const short * codebook = tabindex[tab_num];
        int linbits = g_linbits[tab_num];
        do
        {
            np = *sfb++ / 2;
            pairs_to_decode = MIN(big_val_cnt, np);
            one = *scf++;
            do
            {
                int j, w = 5;
                int leaf = codebook[PEEK_BITS(w)];
                while (leaf < 0)
                {
                    FLUSH_BITS(w);
                    w = leaf & 7;
                    leaf = codebook[PEEK_BITS(w) - (leaf >> 3)];
                }
                FLUSH_BITS(leaf >> 8);

                for (j = 0; j < 2; j++, dst++, leaf >>= 4)
                {
                    int lsb = leaf & 0x0F;
                    if (lsb)
                    {
                        if (lsb == 15 && linbits)
                        {
                            lsb += PEEK_BITS(linbits);
                            FLUSH_BITS(linbits);
                            CHECK_BITS;
                            *dst = one*L3_pow_43(lsb)*((int32_t)bs_cache < 0 ? -1: 1);
                        } else
                        {
                            *dst = g_pow43_signed[lsb*2 + (bs_cache >> 31)]*one;
                        }
                        FLUSH_BITS(1);
                    }
                }
                CHECK_BITS;
            } while (--pairs_to_decode);
        } while ((big_val_cnt -= np) > 0 && --sfb_cnt >= 0 );
    }

    for (np = 1 - big_val_cnt;; dst += 4)
    {
        const uint8_t *codebook_count1 = (gr_info->count1_table) ? tab33 : tab32;
        int leaf = codebook_count1[PEEK_BITS(4)];
        if (!(leaf & 8))
        {
            leaf = codebook_count1[(leaf >> 3) + (bs_cache << 4 >> (32 - (leaf & 3)))];
        }
        FLUSH_BITS(leaf & 7);
        if (BSPOS > layer3gr_limit)
        {
            break;
        }
#define RELOAD_SCALEFACTOR  if (!--np) {np = *sfb++/2; if (!np) break; one = *scf++;}
#define DEQ_COUNT1(s) if (leaf & (128 >> s)) {dst[s] = ((int32_t)bs_cache < 0)?-one:one; FLUSH_BITS(1)}
        RELOAD_SCALEFACTOR;
        DEQ_COUNT1(0);
        DEQ_COUNT1(1);
        RELOAD_SCALEFACTOR;
        DEQ_COUNT1(2);
        DEQ_COUNT1(3);
        CHECK_BITS;
    }

    bs->pos = layer3gr_limit;
}

static void L3_midside_stereo(float *left, int n)
{
    int i = 0;
    float * right = left + 576;
#if HAVE_SIMD
    if (have_simd()) for (; i < n - 3; i += 4)
    {
        f4 vl = VLD(left+i);
        f4 vr = VLD(right+i);
        VSTORE(left+i, VADD(vl, vr));
        VSTORE(right+i, VSUB(vl, vr));
    }
#endif
    for (; i < n; i++)
    {
        float a = left[i];
        float b = right[i];
        left[i] = a + b;
        right[i] = a - b;
    }
}

static void L3_intensity_stereo_band(float *left, int n, float kl, float kr)
{
    int i;
    for (i = 0; i < n; i++)
    {
        left[i + 576] = left[i]*kr;
        left[i] = left[i]*kl;
    }
}

static void L3_stereo_top_band(const float *right, const uint8_t *sfb, int nbands, int max_band[3])
{
    int i, k;

    max_band[0] = max_band[1] = max_band[2] = -1;

    for (i = 0; i < nbands; i++)
    {
        for (k = 0; k < sfb[i]; k += 2)
        {
            if (right[k] != 0 || right[k + 1] != 0)
            {
                max_band[i % 3] = i;
                break;
            }
        }
        right += sfb[i];
    }
}

static void L3_stereo_process(float *left, const uint8_t *ist_pos, const uint8_t *sfb, const uint8_t *hdr, int max_band[3], int mpeg2_sh)
{
    static const float g_pan[7*2] = { 0,1,0.21132487f,0.78867513f,0.36602540f,0.63397460f,0.5f,0.5f,0.63397460f,0.36602540f,0.78867513f,0.21132487f,1,0 };
    unsigned i, max_pos = HDR_TEST_MPEG1(hdr) ? 7 : 64;

    for (i = 0; sfb[i]; i++)
    {
        unsigned ipos = ist_pos[i];
        if ((int)i > max_band[i % 3] && ipos < max_pos)
        {
            float kl,kr,s=HDR_TEST_MS_STEREO(hdr) ? 1.41421356f : 1;
            if (HDR_TEST_MPEG1(hdr))
            {
                kl = g_pan[2*ipos];
                kr = g_pan[2*ipos + 1];
            } else
            {
                kl = 1;
                kr = L3_ldexp_q2((ipos + 1) >> 1 << mpeg2_sh);
                if (ipos & 1)
                {
                    kl = kr;
                    kr = 1;
                }
            }
            L3_intensity_stereo_band(left, sfb[i], kl*s, kr*s);
        } else if (HDR_TEST_MS_STEREO(hdr))
        {
            L3_midside_stereo(left, sfb[i]);
        }
        left += sfb[i];
    }
}

static void L3_intensity_stereo(float *left, uint8_t *ist_pos, const L3_gr_info_t *gr, const uint8_t *hdr)
{
    int max_band[3], n_sfb = gr->n_long_sfb + gr->n_short_sfb;
    int i, max_blocks = gr->n_short_sfb ? 3 : 1;

    L3_stereo_top_band(left + 576, gr->sfbtab, n_sfb, max_band);
    if (gr->n_long_sfb)
    {
        max_band[0] = max_band[1] = max_band[2] = MAX(MAX(max_band[0], max_band[1]), max_band[2]);
    }
    for (i = 0; i < max_blocks; i++)
    {
        int default_pos = HDR_TEST_MPEG1(hdr) ? 3 : 0;
        int itop = n_sfb - max_blocks + i;
        int prev = itop - max_blocks;
        ist_pos[itop] = max_band[i] >= prev ? default_pos : ist_pos[prev];
    }
    L3_stereo_process(left, ist_pos, gr->sfbtab, hdr, max_band, gr[1].scalefac_compress&1);
}

static void L3_reorder(float *grbuf, float *scratch, const uint8_t *sfb)
{
    int i, len;
    float *src = grbuf, *dst = scratch;

    for (;0 != (len = *sfb); sfb += 3, src += 2*len)
    {
        for (i = 0; i < len; i++, src++)
        {
            *dst++ = src[0*len];
            *dst++ = src[1*len];
            *dst++ = src[2*len];
        }
    }
    memcpy(grbuf, scratch, (dst - scratch) * sizeof(float));
}

static void L3_antialias(float *grbuf, int nbands)
{
    static const float g_aa[2][8] = {
        {0.85749293f,0.88174200f,0.94962865f,0.98331459f,0.99551782f,0.99916056f,0.99989920f,0.99999316f},
        {0.51449576f,0.47173197f,0.31337745f,0.18191320f,0.09457419f,0.04096558f,0.01419856f,0.00369997f}
    };

    for (; nbands > 0; nbands--, grbuf += 18)
    {
        int i = 0;
#if HAVE_SIMD
        if (have_simd()) for (; i < 8; i += 4)
        {
            f4 vu = VLD(grbuf + 18 + i);
            f4 vd = VLD(grbuf + 14 - i);
            f4 vc0 = VLD(g_aa[0] + i);
            f4 vc1 = VLD(g_aa[1] + i);
            vd = VREV(vd);
            VSTORE(grbuf + 18 + i, VSUB(VMUL(vu, vc0), VMUL(vd, vc1)));
            vd = VADD(VMUL(vu, vc1), VMUL(vd, vc0));
            VSTORE(grbuf + 14 - i, VREV(vd));
        }
#endif
        for(; i < 8; i++)
        {
            float u = grbuf[18 + i];
            float d = grbuf[17 - i];
            grbuf[18 + i] = u*g_aa[0][i] - d*g_aa[1][i];
            grbuf[17 - i] = u*g_aa[1][i] + d*g_aa[0][i];
        }
    }
}

static void L3_dct3_9(float *y)
{
    float s0, s1, s2, s3, s4, s5, s6, s7, s8, t0, t2, t4;

    s0 = y[0]; s2 = y[2]; s4 = y[4]; s6 = y[6]; s8 = y[8];
    t0 = s0 + s6*0.5f;
    s0 -= s6;
    t4 = (s4 + s2)*0.93969262f;
    t2 = (s8 + s2)*0.76604444f;
    s6 = (s4 - s8)*0.17364818f;
    s4 += s8 - s2;

    s2 = s0 - s4*0.5f;
    y[4] = s4 + s0;
    s8 = t0 - t2 + s6;
    s0 = t0 - t4 + t2;
    s4 = t0 + t4 - s6;

    s1 = y[1]; s3 = y[3]; s5 = y[5]; s7 = y[7];

    s3 *= 0.86602540f;
    t0 = (s5 + s1)*0.98480775f;
    t4 = (s5 - s7)*0.34202014f;
    t2 = (s1 + s7)*0.64278761f;
    s1 = (s1 - s5 - s7)*0.86602540f;

    s5 = t0 - s3 - t2;
    s7 = t4 - s3 - t0;
    s3 = t4 + s3 - t2;

    y[0] = s4 - s7;
    y[1] = s2 + s1;
    y[2] = s0 - s3;
    y[3] = s8 + s5;
    y[5] = s8 - s5;
    y[6] = s0 + s3;
    y[7] = s2 - s1;
    y[8] = s4 + s7;
}

static void L3_imdct36(float *grbuf, float *overlap, const float *window, int nbands)
{
    int i, j;
    static const float g_twid9[18] = {
        0.73727734f,0.79335334f,0.84339145f,0.88701083f,0.92387953f,0.95371695f,0.97629601f,0.99144486f,0.99904822f,0.67559021f,0.60876143f,0.53729961f,0.46174861f,0.38268343f,0.30070580f,0.21643961f,0.13052619f,0.04361938f
    };

    for (j = 0; j < nbands; j++, grbuf += 18, overlap += 9)
    {
        float co[9], si[9];
        co[0] = -grbuf[0];
        si[0] = grbuf[17];
        for (i = 0; i < 4; i++)
        {
            si[8-2*i] = grbuf[4*i+1] - grbuf[4*i+2];
            co[1+2*i] = grbuf[4*i+1] + grbuf[4*i+2];
            si[7-2*i] = grbuf[4*i+4] - grbuf[4*i+3];
            co[2+2*i] = -(grbuf[4*i+3] + grbuf[4*i+4]);
        }
        L3_dct3_9(co);
        L3_dct3_9(si);

        si[1] = -si[1];
        si[3] = -si[3];
        si[5] = -si[5];
        si[7] = -si[7];

        i = 0;

#if HAVE_SIMD
        if (have_simd()) for (; i < 8; i += 4)
        {
            f4 vovl = VLD(overlap + i);
            f4 vc = VLD(co + i);
            f4 vs = VLD(si + i);
            f4 vr0 = VLD(g_twid9 + i);
            f4 vr1 = VLD(g_twid9 + 9 + i);
            f4 vw0 = VLD(window + i);
            f4 vw1 = VLD(window + 9 + i);
            f4 vsum = VADD(VMUL(vc, vr1), VMUL(vs, vr0));
            VSTORE(overlap + i, VSUB(VMUL(vc, vr0), VMUL(vs, vr1)));
            VSTORE(grbuf + i, VSUB(VMUL(vovl, vw0), VMUL(vsum, vw1)));
            vsum = VADD(VMUL(vovl, vw1), VMUL(vsum, vw0));
            VSTORE(grbuf + 14 - i, VREV(vsum));
        }
#endif
        for (; i < 9; i++)
        {
            float ovl = overlap[i];
            float sum  = co[i]*g_twid9[9 + i] + si[i]*g_twid9[0 + i];
            overlap[i] = co[i]*g_twid9[0 + i] - si[i]*g_twid9[9 + i];
            grbuf[i]    = ovl*window[0 + i] - sum*window[9 + i];
            grbuf[17-i] = ovl*window[9 + i] + sum*window[0 + i];
        }
    }
}

static void L3_idct3(float x0, float x1, float x2, float *dst)
{
    float m1 = x1*0.86602540f;
    float a1 = x0 - x2*0.5f;
    dst[1] = x0 + x2;
    dst[0] = a1 + m1;
    dst[2] = a1 - m1;
}

static void L3_imdct12(float *x, float *dst, float *overlap)
{
    static const float g_twid3[6] = { 0.79335334f,0.92387953f,0.99144486f, 0.60876143f,0.38268343f,0.13052619f };
    float co[3], si[3];
    int i;

    L3_idct3(-x[0], x[6] + x[3], x[12] + x[9], co);
    L3_idct3(x[15], x[12] - x[9], x[6] - x[3], si);
    si[1] = -si[1];

    for (i = 0; i < 3; i++)
    {
        float ovl  = overlap[i];
        float sum  = co[i]*g_twid3[3 + i] + si[i]*g_twid3[0 + i];
        overlap[i] = co[i]*g_twid3[0 + i] - si[i]*g_twid3[3 + i];
        dst[i]     = ovl*g_twid3[2 - i] - sum*g_twid3[5 - i];
        dst[5 - i] = ovl*g_twid3[5 - i] + sum*g_twid3[2 - i];
    }
}

static void L3_imdct_short(float *grbuf, float *overlap, int nbands)
{
    for (;nbands > 0; nbands--, overlap += 9, grbuf += 18)
    {
        float tmp[18];
        memcpy(tmp, grbuf, sizeof(tmp));
        memcpy(grbuf, overlap, 6*sizeof(float));
        L3_imdct12(tmp, grbuf + 6, overlap + 6);
        L3_imdct12(tmp + 1, grbuf + 12, overlap + 6);
        L3_imdct12(tmp + 2, overlap, overlap + 6);
    }
}

static void L3_change_sign(float *grbuf)
{
    int b, i;
    for (b = 0, grbuf += 18; b < 32; b += 2, grbuf += 36)
        for (i = 1; i < 18; i += 2)
            grbuf[i] = -grbuf[i];
}

static void L3_imdct_gr(float *grbuf, float *overlap, unsigned block_type, unsigned n_long_bands)
{
    static const float g_mdct_window[2][18] = {
        { 0.99904822f,0.99144486f,0.97629601f,0.95371695f,0.92387953f,0.88701083f,0.84339145f,0.79335334f,0.73727734f,0.04361938f,0.13052619f,0.21643961f,0.30070580f,0.38268343f,0.46174861f,0.53729961f,0.60876143f,0.67559021f },
        { 1,1,1,1,1,1,0.99144486f,0.92387953f,0.79335334f,0,0,0,0,0,0,0.13052619f,0.38268343f,0.60876143f }
    };
    if (n_long_bands)
    {
        L3_imdct36(grbuf, overlap, g_mdct_window[0], n_long_bands);
        grbuf += 18*n_long_bands;
        overlap += 9*n_long_bands;
    }
    if (block_type == SHORT_BLOCK_TYPE)
        L3_imdct_short(grbuf, overlap, 32 - n_long_bands);
    else
        L3_imdct36(grbuf, overlap, g_mdct_window[block_type == STOP_BLOCK_TYPE], 32 - n_long_bands);
}

static void L3_save_reservoir(mp3dec_t *h, mp3dec_scratch_t *s)
{
    int pos = (s->bs.pos + 7)/8u;
    int remains = s->bs.limit/8u - pos;
    if (remains > MAX_BITRESERVOIR_BYTES)
    {
        pos += remains - MAX_BITRESERVOIR_BYTES;
        remains = MAX_BITRESERVOIR_BYTES;
    }
    if (remains > 0)
    {
        memmove(h->reserv_buf, s->maindata + pos, remains);
    }
    h->reserv = remains;
}

static int L3_restore_reservoir(mp3dec_t *h, bs_t *bs, mp3dec_scratch_t *s, int main_data_begin)
{
    int frame_bytes = (bs->limit - bs->pos)/8;
    int bytes_have = MIN(h->reserv, main_data_begin);
    memcpy(s->maindata, h->reserv_buf + MAX(0, h->reserv - main_data_begin), MIN(h->reserv, main_data_begin));
    memcpy(s->maindata + bytes_have, bs->buf + bs->pos/8, frame_bytes);
    bs_init(&s->bs, s->maindata, bytes_have + frame_bytes);
    return h->reserv >= main_data_begin;
}

static void L3_decode(mp3dec_t *h, mp3dec_scratch_t *s, L3_gr_info_t *gr_info, int nch)
{
    int ch;

    for (ch = 0; ch < nch; ch++)
    {
        int layer3gr_limit = s->bs.pos + gr_info[ch].part_23_length;
        L3_decode_scalefactors(h->header, s->ist_pos[ch], &s->bs, gr_info + ch, s->scf, ch);
        L3_huffman(s->grbuf[ch], &s->bs, gr_info + ch, s->scf, layer3gr_limit);
    }

    if (HDR_TEST_I_STEREO(h->header))
    {
        L3_intensity_stereo(s->grbuf[0], s->ist_pos[1], gr_info, h->header);
    } else if (HDR_IS_MS_STEREO(h->header))
    {
        L3_midside_stereo(s->grbuf[0], 576);
    }

    for (ch = 0; ch < nch; ch++, gr_info++)
    {
        int aa_bands = 31;
        int n_long_bands = (gr_info->mixed_block_flag ? 2 : 0) << (HDR_GET_MY_SAMPLE_RATE(h->header) == 2);

        if (gr_info->n_short_sfb)
        {
            aa_bands = n_long_bands - 1;
            L3_reorder(s->grbuf[ch] + n_long_bands*18, s->syn[0], gr_info->sfbtab + gr_info->n_long_sfb);
        }

        L3_antialias(s->grbuf[ch], aa_bands);
        L3_imdct_gr(s->grbuf[ch], h->mdct_overlap[ch], gr_info->block_type, n_long_bands);
        L3_change_sign(s->grbuf[ch]);
    }
}

static void mp3d_DCT_II(float *grbuf, int n)
{
    static const float g_sec[24] = {
        10.19000816f,0.50060302f,0.50241929f,3.40760851f,0.50547093f,0.52249861f,2.05778098f,0.51544732f,0.56694406f,1.48416460f,0.53104258f,0.64682180f,1.16943991f,0.55310392f,0.78815460f,0.97256821f,0.58293498f,1.06067765f,0.83934963f,0.62250412f,1.72244716f,0.74453628f,0.67480832f,5.10114861f
    };
    int i, k = 0;
#if HAVE_SIMD
    if (have_simd()) for (; k < n; k += 4)
    {
        f4 t[4][8], *x;
        float * y = grbuf + k;

        for (x = t[0], i = 0; i < 8; i++, x++)
        {
            f4 x0 = VLD(&y[i*18]);
            f4 x1 = VLD(&y[(15-i)*18]);
            f4 x2 = VLD(&y[(16+i)*18]);
            f4 x3 = VLD(&y[(31-i)*18]);
            f4 t0 = VADD(x0, x3);
            f4 t1 = VADD(x1, x2);
            f4 t2 = VMUL_S(VSUB(x1, x2), g_sec[3*i+0]);
            f4 t3 = VMUL_S(VSUB(x0, x3), g_sec[3*i+1]);
            x[0] = VADD(t0, t1);
            x[8] = VMUL_S(VSUB(t0, t1), g_sec[3*i+2]);
            x[16] = VADD(t3, t2);
            x[24] = VMUL_S(VSUB(t3, t2), g_sec[3*i+2]);
        }
        for (x = t[0], i = 0; i < 4; i++, x += 8)
        {
            f4 x0 = x[0], x1 = x[1], x2 = x[2], x3 = x[3], x4 = x[4], x5 = x[5], x6 = x[6], x7 = x[7], xt;
            xt = VSUB(x0, x7); x0 = VADD(x0, x7);
            x7 = VSUB(x1, x6); x1 = VADD(x1, x6);
            x6 = VSUB(x2, x5); x2 = VADD(x2, x5);
            x5 = VSUB(x3, x4); x3 = VADD(x3, x4);
            x4 = VSUB(x0, x3); x0 = VADD(x0, x3);
            x3 = VSUB(x1, x2); x1 = VADD(x1, x2);
            x[0] = VADD(x0, x1);
            x[4] = VMUL_S(VSUB(x0, x1), 0.70710677f);
            x5 = VADD(x5, x6);
            x6 = VMUL_S(VADD(x6, x7), 0.70710677f);
            x7 = VADD(x7, xt);
            x3 = VMUL_S(VADD(x3, x4), 0.70710677f);
            x5 = VSUB(x5, VMUL_S(x7, 0.198912367f)); // rotate by PI/8
            x7 = VADD(x7, VMUL_S(x5, 0.382683432f));
            x5 = VSUB(x5, VMUL_S(x7, 0.198912367f));
            x0 = VSUB(xt, x6); xt = VADD(xt, x6);
            x[1] = VMUL_S(VADD(xt, x7), 0.50979561f);
            x[2] = VMUL_S(VADD(x4, x3), 0.54119611f);
            x[3] = VMUL_S(VSUB(x0, x5), 0.60134488f);
            x[5] = VMUL_S(VADD(x0, x5), 0.89997619f);
            x[6] = VMUL_S(VSUB(x4, x3), 1.30656302f);
            x[7] = VMUL_S(VSUB(xt, x7), 2.56291556f);
        }

        if (k > n-3)
        {
#if HAVE_SSE
#define VSAVE2(i, v) _mm_storel_pi((__m64 *)&y[i*18], v)
#else
#define VSAVE2(i, v) vst1_f32((float32_t *)&y[i*18],  vget_low_f32(v))
#endif
            for (i = 0; i < 7; i++, y += 4*18)
            {
                f4 s = VADD(t[3][i], t[3][i + 1]);
                VSAVE2(0, t[0][i]);
                VSAVE2(1, VADD(t[2][i], s));
                VSAVE2(2, VADD(t[1][i], t[1][i + 1]));
                VSAVE2(3, VADD(t[2][1 + i], s));
            }
            VSAVE2(0, t[0][7]);
            VSAVE2(1, VADD(t[2][7], t[3][7]));
            VSAVE2(2, t[1][7]);
            VSAVE2(3, t[3][7]);
        } else
        {
#define VSAVE4(i, v) VSTORE(&y[i*18], v)
            for (i = 0; i < 7; i++, y += 4*18)
            {
                f4 s = VADD(t[3][i], t[3][i + 1]);
                VSAVE4(0, t[0][i]);
                VSAVE4(1, VADD(t[2][i], s));
                VSAVE4(2, VADD(t[1][i], t[1][i + 1]));
                VSAVE4(3, VADD(t[2][1 + i], s));
            }
            VSAVE4(0, t[0][7]);
            VSAVE4(1, VADD(t[2][7], t[3][7]));
            VSAVE4(2, t[1][7]);
            VSAVE4(3, t[3][7]);
        }
    } else
#endif
    for (; k < n; k++)
    {
        float t[4][8], *x, *y = grbuf + k;

        for (x = t[0], i = 0; i < 8; i++, x++)
        {
            float x0 = y[i*18];
            float x1 = y[(15 - i)*18];
            float x2 = y[(16 + i)*18];
            float x3 = y[(31 - i)*18];
            float t0 = x0 + x3;
            float t1 = x1 + x2;
            float t2 = (x1 - x2)*g_sec[3*i + 0];
            float t3 = (x0 - x3)*g_sec[3*i + 1];
            x[0] = t0 + t1;
            x[8] = (t0 - t1)*g_sec[3*i + 2];
            x[16] = t3 + t2;
            x[24] = (t3 - t2)*g_sec[3*i + 2];
        }
        for (x = t[0], i = 0; i < 4; i++, x += 8)
        {
            float x0 = x[0], x1 = x[1], x2 = x[2], x3 = x[3], x4 = x[4], x5 = x[5], x6 = x[6], x7 = x[7], xt;
            xt = x0 - x7; x0 += x7;
            x7 = x1 - x6; x1 += x6;
            x6 = x2 - x5; x2 += x5;
            x5 = x3 - x4; x3 += x4;
            x4 = x0 - x3; x0 += x3;
            x3 = x1 - x2; x1 += x2;
            x[0] = x0 + x1;
            x[4] = (x0 - x1)*0.70710677f;
            x5 =  x5 + x6;
            x6 = (x6 + x7)*0.70710677f;
            x7 =  x7 + xt;
            x3 = (x3 + x4)*0.70710677f;
            x5 -= x7*0.198912367f;  // rotate by PI/8
            x7 += x5*0.382683432f;
            x5 -= x7*0.198912367f;
            x0 = xt - x6; xt += x6;
            x[1] = (xt + x7)*0.50979561f;
            x[2] = (x4 + x3)*0.54119611f;
            x[3] = (x0 - x5)*0.60134488f;
            x[5] = (x0 + x5)*0.89997619f;
            x[6] = (x4 - x3)*1.30656302f;
            x[7] = (xt - x7)*2.56291556f;

        }
        for (i = 0; i < 7; i++, y += 4*18)
        {
            y[0*18] = t[0][i];
            y[1*18] = t[2][i] + t[3][i] + t[3][i + 1];
            y[2*18] = t[1][i] + t[1][i + 1];
            y[3*18] = t[2][i + 1] + t[3][i] + t[3][i + 1];
        }
        y[0*18] = t[0][7];
        y[1*18] = t[2][7] + t[3][7];
        y[2*18] = t[1][7];
        y[3*18] = t[3][7];
    }
}

static short mp3d_scale_pcm(float sample)
{
    int s = (int)(sample + .5f);
    s -= (s < 0);   // away from zero, to be compliant
    if (s >  32767) return (short) 32767;
    if (s < -32768) return (short)-32768;
    return (short)s;
}

static void mp3d_synth_pair(short *pcm, int nch, const float *z)
{
    float a;
    a  = (z[14*64] - z[    0]) * 29;
    a += (z[ 1*64] + z[13*64]) * 213;
    a += (z[12*64] - z[ 2*64]) * 459;
    a += (z[ 3*64] + z[11*64]) * 2037;
    a += (z[10*64] - z[ 4*64]) * 5153;
    a += (z[ 5*64] + z[ 9*64]) * 6574;
    a += (z[ 8*64] - z[ 6*64]) * 37489;
    a +=  z[ 7*64]             * 75038;
    pcm[0] = mp3d_scale_pcm(a);

    z += 2;
    a  = z[14*64] * 104;
    a += z[12*64] * 1567;
    a += z[10*64] * 9727;
    a += z[ 8*64] * 64019;
    a += z[ 6*64] * -9975;
    a += z[ 4*64] * -45;
    a += z[ 2*64] * 146;
    a += z[ 0*64] * -5;
    pcm[16*nch] = mp3d_scale_pcm(a);
}

static void mp3d_synth(float *xl, short *dstl, int nch, float *lins)
{
    int i;
    float *xr = xl + 576*(nch - 1);
    short *dstr = dstl + (nch - 1);

    static const float g_win[] = {
        -1,26,-31,208,218,401,-519,2063,2000,4788,-5517,7134,5959,35640,-39336,74992,
        -1,24,-35,202,222,347,-581,2080,1952,4425,-5879,7640,5288,33791,-41176,74856,
        -1,21,-38,196,225,294,-645,2087,1893,4063,-6237,8092,4561,31947,-43006,74630,
        -1,19,-41,190,227,244,-711,2085,1822,3705,-6589,8492,3776,30112,-44821,74313,
        -1,17,-45,183,228,197,-779,2075,1739,3351,-6935,8840,2935,28289,-46617,73908,
        -1,16,-49,176,228,153,-848,2057,1644,3004,-7271,9139,2037,26482,-48390,73415,
        -2,14,-53,169,227,111,-919,2032,1535,2663,-7597,9389,1082,24694,-50137,72835,
        -2,13,-58,161,224,72,-991,2001,1414,2330,-7910,9592,70,22929,-51853,72169,
        -2,11,-63,154,221,36,-1064,1962,1280,2006,-8209,9750,-998,21189,-53534,71420,
        -2,10,-68,147,215,2,-1137,1919,1131,1692,-8491,9863,-2122,19478,-55178,70590,
        -3,9,-73,139,208,-29,-1210,1870,970,1388,-8755,9935,-3300,17799,-56778,69679,
        -3,8,-79,132,200,-57,-1283,1817,794,1095,-8998,9966,-4533,16155,-58333,68692,
        -4,7,-85,125,189,-83,-1356,1759,605,814,-9219,9959,-5818,14548,-59838,67629,
        -4,7,-91,117,177,-106,-1428,1698,402,545,-9416,9916,-7154,12980,-61289,66494,
        -5,6,-97,111,163,-127,-1498,1634,185,288,-9585,9838,-8540,11455,-62684,65290
    };
    float * zlin = lins + 15*64;
    const float * w = g_win;

    zlin[4*15]     = xl[18*16];
    zlin[4*15 + 1] = xr[18*16];
    zlin[4*15 + 2] = xl[0];
    zlin[4*15 + 3] = xr[0];

    zlin[4*31]     = xl[1 + 18*16];
    zlin[4*31 + 1] = xr[1 + 18*16];
    zlin[4*31 + 2] = xl[1];
    zlin[4*31 + 3] = xr[1];

    mp3d_synth_pair(dstr, nch, lins + 4*15 + 1);
    mp3d_synth_pair(dstr + 32*nch, nch, lins + 4*15 + 64 + 1);
    mp3d_synth_pair(dstl, nch, lins + 4*15);
    mp3d_synth_pair(dstl + 32*nch, nch, lins + 4*15 + 64);

#if HAVE_SIMD
    if (have_simd()) for (i = 14; i >= 0; i--)
    {
#define VLOAD(k) f4 w0 = VSET(*w++); f4 w1 = VSET(*w++); f4 vz = VLD(&zlin[4*i - 64*k]); f4 vy = VLD(&zlin[4*i - 64*(15 - k)]);
#define V0(k) {VLOAD(k) b =         VADD(VMUL(vz, w1), VMUL(vy, w0)) ; a =         VSUB(VMUL(vz, w0),VMUL(vy, w1));  }
#define V1(k) {VLOAD(k) b = VADD(b, VADD(VMUL(vz, w1), VMUL(vy, w0))); a = VADD(a, VSUB(VMUL(vz, w0),VMUL(vy, w1))); }
#define V2(k) {VLOAD(k) b = VADD(b, VADD(VMUL(vz, w1), VMUL(vy, w0))); a = VADD(a, VSUB(VMUL(vy, w1),VMUL(vz, w0))); }
        f4 a,b;
        zlin[4*i]     = xl[18*(31 - i)];
        zlin[4*i + 1] = xr[18*(31 - i)];
        zlin[4*i + 2] = xl[1 + 18*(31 - i)];
        zlin[4*i + 3] = xr[1 + 18*(31 - i)];
        zlin[4*i + 64] = xl[1 + 18*(1 + i)];
        zlin[4*i + 64 + 1] = xr[1 + 18*(1 + i)];
        zlin[4*i - 64 + 2] = xl[18*(1 + i)];
        zlin[4*i - 64 + 3] = xr[18*(1 + i)];

        V0(0) V2(1) V1(2) V2(3) V1(4) V2(5) V1(6) V2(7)

        {
#if HAVE_SSE
            __m128i pcm8 = _mm_packs_epi32(_mm_cvtps_epi32(a), _mm_cvtps_epi32(b));
            dstr[(15 - i)*nch] = _mm_extract_epi16(pcm8, 1);
            dstr[(17 + i)*nch] = _mm_extract_epi16(pcm8, 5);
            dstl[(15 - i)*nch] = _mm_extract_epi16(pcm8, 0);
            dstl[(17 + i)*nch] = _mm_extract_epi16(pcm8, 4);
            dstr[(47 - i)*nch] = _mm_extract_epi16(pcm8, 3);
            dstr[(49 + i)*nch] = _mm_extract_epi16(pcm8, 7);
            dstl[(47 - i)*nch] = _mm_extract_epi16(pcm8, 2);
            dstl[(49 + i)*nch] = _mm_extract_epi16(pcm8, 6);
#else
            int16x4_t pcma, pcmb;
            a = VADD(a, VSET(0.5f));
            b = VADD(b, VSET(0.5f));
            pcma = vqmovn_s32(vaddq_s32(vcvtq_s32_f32(a), vreinterpretq_s32_u32(vcltq_f32(a, VSET(0)))));
            pcmb = vqmovn_s32(vaddq_s32(vcvtq_s32_f32(b), vreinterpretq_s32_u32(vcltq_f32(b, VSET(0)))));
            vst1_lane_s16(dstr + (15 - i)*nch, pcma, 1);
            vst1_lane_s16(dstr + (17 + i)*nch, pcmb, 1);
            vst1_lane_s16(dstl + (15 - i)*nch, pcma, 0);
            vst1_lane_s16(dstl + (17 + i)*nch, pcmb, 0);
            vst1_lane_s16(dstr + (47 - i)*nch, pcma, 3);
            vst1_lane_s16(dstr + (49 + i)*nch, pcmb, 3);
            vst1_lane_s16(dstl + (47 - i)*nch, pcma, 2);
            vst1_lane_s16(dstl + (49 + i)*nch, pcmb, 2);
#endif
        }
    } else
#endif
    for (i = 14; i >= 0; i--)
    {
#define LOAD(k) float w0 = *w++; float w1 = *w++; float * vz = &zlin[4*i-k*64]; float * vy = &zlin[4*i-(15-k)*64];
#define S0(k) {int j; LOAD(k); for (j = 0; j < 4; j++) b[j]  = vz[j] * w1 + vy[j] * w0, a[j]  = vz[j] * w0 - vy[j] * w1;}
#define S1(k) {int j; LOAD(k); for (j = 0; j < 4; j++) b[j] += vz[j] * w1 + vy[j] * w0, a[j] += vz[j] * w0 - vy[j] * w1;}
#define S2(k) {int j; LOAD(k); for (j = 0; j < 4; j++) b[j] += vz[j] * w1 + vy[j] * w0, a[j] += vy[j] * w1 - vz[j] * w0;}
        float a[4], b[4];

        zlin[4*i]     = xl[18*(31 - i)];
        zlin[4*i + 1] = xr[18*(31 - i)];
        zlin[4*i + 2] = xl[1 + 18*(31 - i)];
        zlin[4*i + 3] = xr[1 + 18*(31 - i)];
        zlin[4*(i + 16)]   = xl[1 + 18*(1 + i)];
        zlin[4*(i + 16) + 1] = xr[1 + 18*(1 + i)];
        zlin[4*(i - 16) + 2] = xl[18*(1 + i)];
        zlin[4*(i - 16) + 3] = xr[18*(1 + i)];

        S0(0) S2(1) S1(2) S2(3) S1(4) S2(5) S1(6) S2(7)

        dstr[(15 - i)*nch] = mp3d_scale_pcm(a[1]);
        dstr[(17 + i)*nch] = mp3d_scale_pcm(b[1]);
        dstl[(15 - i)*nch] = mp3d_scale_pcm(a[0]);
        dstl[(17 + i)*nch] = mp3d_scale_pcm(b[0]);
        dstr[(47 - i)*nch] = mp3d_scale_pcm(a[3]);
        dstr[(49 + i)*nch] = mp3d_scale_pcm(b[3]);
        dstl[(47 - i)*nch] = mp3d_scale_pcm(a[2]);
        dstl[(49 + i)*nch] = mp3d_scale_pcm(b[2]);
    }
}

static void mp3d_synth_granule(float *qmf_state, float *grbuf, int nbands, int nch, short *pcm, float *lins)
{
    int i;
    for (i = 0; i < nch; i++)
    {
        mp3d_DCT_II(grbuf + 576*i, nbands);
    }

    memcpy(lins, qmf_state, sizeof(float)*15*64);

    for (i = 0; i < nbands; i += 2)
    {
        mp3d_synth(grbuf + i, pcm + 32*nch*i, nch, lins + i*64);
    }

    if (nch == 1)
    {
        for (i = 0; i < 15*64; i += 2)
        {
            qmf_state[i] = lins[nbands*64 + i];
        }
    } else
    {
        memcpy(qmf_state, lins + nbands*64, sizeof(float)*15*64);
    }
}

static int mp3d_match_frame(const uint8_t *hdr, int mp3_bytes, int frame_bytes)
{
    int i, nmatch;
    for (i = 0, nmatch = 0; nmatch < MAX_FRAME_SYNC_MATCHES; nmatch++)
    {
        i += hdr_frame_bytes(hdr + i, frame_bytes) + hdr_padding(hdr + i);
        if (i + HDR_SIZE > mp3_bytes)
            return nmatch > 0;
        if (!hdr_compare(hdr, hdr + i))
            return 0;
    }
    return 1;
}

static int mp3d_find_frame(const uint8_t *mp3, int mp3_bytes, int *free_format_bytes, int *ptr_frame_bytes)
{
    int i, k;
    for (i = 0; i < mp3_bytes - HDR_SIZE; i++, mp3++)
    {
        if (hdr_valid(mp3))
        {
            int frame_bytes = hdr_frame_bytes(mp3, *free_format_bytes);
            int frame_and_padding = frame_bytes + hdr_padding(mp3);

            for (k = HDR_SIZE; !frame_bytes && k < MAX_FREE_FORMAT_FRAME_SIZE && i + 2*k < mp3_bytes - HDR_SIZE; k++)
            {
                if (hdr_compare(mp3, mp3 + k))
                {
                    int fb = k - hdr_padding(mp3);
                    int nextfb = fb + hdr_padding(mp3 + k);
                    if (i + k + nextfb + HDR_SIZE > mp3_bytes || !hdr_compare(mp3, mp3 + k + nextfb))
                        continue;
                    frame_and_padding = k;
                    frame_bytes = fb;
                    *free_format_bytes = fb;
                }
            }

            if (frame_bytes && i + frame_and_padding <= mp3_bytes &&
                mp3d_match_frame(mp3, MIN((frame_bytes + 1)*4, mp3_bytes - i), frame_bytes))
            {
                *ptr_frame_bytes = frame_and_padding;
                return i;
            }
            *free_format_bytes = 0;
        }
    }
    *ptr_frame_bytes = 0;
    return i;
}

int mp3dec_decode_frame(mp3dec_t *dec, const uint8_t *mp3, int mp3_bytes, short *pcm, mp3dec_frame_info_t *info)
{
    int i = 0, igr, frame_size = 0, success = 1;
    const uint8_t *hdr;
    bs_t bs_frame[1];
    mp3dec_scratch_t scratch;

    if (dec->header[0] == 0xff && hdr_compare(dec->header, mp3))
    {
        frame_size = hdr_frame_bytes(mp3, dec->free_format_bytes) + hdr_padding(mp3);
        if (frame_size != mp3_bytes && (frame_size + HDR_SIZE > mp3_bytes || !hdr_compare(mp3, mp3 + frame_size)))
        {
            frame_size = 0;
        }
    }
    if (!frame_size)
    {
        memset(dec, 0, sizeof(mp3dec_t));
        i = mp3d_find_frame(mp3, mp3_bytes, &dec->free_format_bytes, &frame_size);
        if (!frame_size || i + frame_size > mp3_bytes)
        {
            info->frame_bytes = i;
            return 0;
        }
    }

    hdr = mp3 + i;
    memcpy(dec->header, hdr, HDR_SIZE);
    info->frame_bytes = i + frame_size;
    info->channels = HDR_IS_MONO(hdr) ? 1 : 2;
    info->hz = hdr_sample_rate_hz(hdr);
    info->layer = 4 - HDR_GET_LAYER(hdr);
    info->bitrate_kbps = hdr_bitrate_kbps(hdr);

    bs_init(bs_frame, hdr + HDR_SIZE, frame_size - HDR_SIZE);
    if (HDR_IS_CRC(hdr))
    {
        get_bits(bs_frame, 16);
    }

    if (info->layer == 3)
    {
        int main_data_begin = L3_read_side_info(bs_frame, scratch.gr_info, hdr);
        if (main_data_begin < 0)
        {
            mp3dec_init(dec);
            return 0;
        }
        success = L3_restore_reservoir(dec, bs_frame, &scratch, main_data_begin);
        if (success)
        {
            for (igr = 0; igr < (HDR_TEST_MPEG1(hdr) ? 2 : 1); igr++, pcm += 576*info->channels)
            {
                memset(scratch.grbuf[0], 0, 576*2*sizeof(float));
                L3_decode(dec, &scratch, scratch.gr_info + igr*info->channels, info->channels);
                mp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 18, info->channels, pcm, scratch.syn[0]);
            }
        }
        L3_save_reservoir(dec, &scratch);
    } else
    {
        L12_scale_info sci[1];
        L12_read_scale_info(hdr, bs_frame, sci);

        memset(scratch.grbuf[0], 0, 576*2*sizeof(float));
        for (i = 0, igr = 0; igr < 3; igr++)
        {
            if (12 == (i += L12_dequantize_granule(scratch.grbuf[0] + i, bs_frame, sci, info->layer|1)))
            {
                i = 0;
                L12_apply_scf_384(sci, sci->scf + igr, scratch.grbuf[0]);
                mp3d_synth_granule(dec->qmf_state, scratch.grbuf[0], 12, info->channels, pcm, scratch.syn[0]);
                memset(scratch.grbuf[0], 0, 576*2*sizeof(float));
                pcm += 384*info->channels;
            }
            if (bs_frame->pos > bs_frame->limit)
            {
                mp3dec_init(dec);
                return 0;
            }
        }
    }
    return success*hdr_frame_samples(dec->header);
}

void mp3dec_init(mp3dec_t *dec)
{
    dec->header[0] = 0;
}

#ifdef minimp3_test
#include <stdio.h>
#include <math.h>

static char *wav_header(int hz, int ch, int bips, int data_bytes)
{
    static char hdr[44] = "RIFFsizeWAVEfmt \x10\0\0\0\1\0ch_hz_abpsbabsdatasize";
    unsigned long nAvgBytesPerSec = bips*ch*hz >> 3;
    unsigned int nBlockAlign      = bips*ch >> 3;

    *(int *  )(hdr + 0x04) = 44 + data_bytes - 8;   // File size - 8
    *(short *)(hdr + 0x14) = 1;                     // Integer PCM format
    *(short *)(hdr + 0x16) = ch;
    *(int *  )(hdr + 0x18) = hz;
    *(int *  )(hdr + 0x1C) = nAvgBytesPerSec;
    *(short *)(hdr + 0x20) = nBlockAlign;
    *(short *)(hdr + 0x22) = bips;
    *(int *  )(hdr + 0x28) = data_bytes;
    return hdr;
}

static void decode_file(FILE *file_mp3, FILE *file_wav, FILE *file_ref)
{
    static mp3dec_t mp3d = { 0, };
    mp3dec_frame_info_t info;
    int i, data_bytes, samples, total_samples = 0, nbuf = 0, maxdiff = 0;
    double MSE = 0.0, psnr;
    unsigned char buf[4096];

    mp3dec_init(&mp3d);

    //fwrite(wav_header(0, 0, 0, 0), 1, 44, file_wav);

    do
    {
        short pcm[2*1152], pcm2[2*1152];
        nbuf += fread(buf + nbuf, 1, sizeof(buf) - nbuf, file_mp3);
        samples = mp3dec_decode_frame(&mp3d, buf, nbuf, pcm, &info);
        if (samples)
        {
            fread(pcm2, 1, 2*info.channels*samples, file_ref);
            total_samples += samples*info.channels;
            for (i = 0; i < samples*info.channels; i++)
            {
                int MSEtemp = abs((int)pcm[i] - (int)pcm2[i]);
                if (MSEtemp > maxdiff)
                    maxdiff = MSEtemp;
                MSE += MSEtemp*MSEtemp;
            }
            fwrite(pcm, samples, 2*info.channels, file_wav);
        }
        memmove(buf, buf + info.frame_bytes, nbuf -= info.frame_bytes);
    } while (info.frame_bytes);

    MSE /= total_samples;
    if (0 == MSE)
        psnr = 99.0;
    else
        psnr = 10.0*log10(((double)0x7fff*0x7fff)/MSE);
    printf("samples=%d max_diff=%d PSNR=%f\n", total_samples, maxdiff, psnr);
    if (psnr < 96)
    {
        printf("PSNR compliance failed\n");
        exit(1);
    }

    //data_bytes = ftell(file_wav) - 44;
    //rewind(file_wav);
    //fwrite(wav_header(info.hz, info.channels, 16, data_bytes), 1, 44, file_wav);
    fclose(file_wav);
    fclose(file_mp3);
}

int main(int argc, char *argv[])
{
    char *input_file_name  = (argc > 1) ? argv[1] : NULL;
    char *output_file_name = (argc > 2) ? argv[2] : NULL;
    char *ref_file_name    = (argc > 3) ? argv[3] : NULL;
    if (!input_file_name || !output_file_name || !ref_file_name)
    {
        printf("error: no file names given\n");
        return 1;
    }
    decode_file(fopen(input_file_name, "rb"), fopen(output_file_name, "wb"), fopen(ref_file_name, "rb"));
    return 0;
}
#endif