Fix for MiniMP3 with NEON intrinsics

[alure.git] / src / decoders / minimp3.h

#ifndef MINIMP3_H
#define MINIMP3_H
/*
    https://github.com/lieff/minimp3
    To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this software to the public domain worldwide.
    This software is distributed without any warranty.
    See <http://creativecommons.org/publicdomain/zero/1.0/>.
*/

#define MINIMP3_MAX_SAMPLES_PER_FRAME (1152*2)

typedef struct
{
    int frame_bytes, channels, hz, layer, bitrate_kbps;
} mp3dec_frame_info_t;

typedef struct
{
    float mdct_overlap[2][9*32], qmf_state[15*2*32];
    int reserv, free_format_bytes;
    unsigned char header[4], reserv_buf[511];
} mp3dec_t;

#ifdef __cplusplus
extern "C" {
#endif

void mp3dec_init(mp3dec_t *dec);
int mp3dec_decode_frame(mp3dec_t *dec, const unsigned char *mp3, int mp3_bytes, float *pcm, mp3dec_frame_info_t *info);
int mp3dec_decode_frame_s16(mp3dec_t *dec, const unsigned char *mp3, int mp3_bytes, short *pcm, mp3dec_frame_info_t *info);

#ifdef __cplusplus
}
#endif

#ifdef MINIMP3_IMPLEMENTATION

#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 MINIMP3_MIN(a, b)           ((a) > (b) ? (b) : (a))
#define MINIMP3_MAX(a, b)           ((a) < (b) ? (b) : (a))

#if !defined(MINIMP3_NO_SIMD)

#if !defined(MINIMP3_ONLY_SIMD) && (defined(_M_X64) || defined(_M_ARM64) || defined(__x86_64__) || defined(__aarch64__))
/* x64 always have SSE2, arm64 always have neon, no need for generic code */
#define MINIMP3_ONLY_SIMD
#endif

#if (defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))) || ((defined(__i386__) || defined(__x86_64__)) && defined(__SSE2__))
#if defined(_MSC_VER)
#include <intrin.h>
#endif
#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;
#if defined(_MSC_VER) || defined(MINIMP3_ONLY_SIMD)
#define minimp3_cpuid __cpuid
#else
static __inline__ __attribute__((always_inline)) void minimp3_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()
{
#ifdef MINIMP3_ONLY_SIMD
    return 1;
#else
    static int g_have_simd;
    int CPUInfo[4];
#ifdef MINIMP3_TEST
    static int g_counter;
    if (g_counter++ > 100)
        return 0;
#endif
    if (g_have_simd)
        goto end;
    minimp3_cpuid(CPUInfo, 0);
    g_have_simd = 1;
    if (CPUInfo[0] > 0)
    {
        minimp3_cpuid(CPUInfo, 1);
        g_have_simd = (CPUInfo[3] & (1 << 26)) + 1; /* SSE2 */
    }
end:
    return g_have_simd - 1;
#endif
}
#elif defined(__ARM_NEON) || defined(__aarch64__)
#include <arm_neon.h>
#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) vcombine_f32(vget_high_f32(vrev64q_f32(x)), vget_low_f32(vrev64q_f32(x)))
typedef float32x4_t f4;
static int have_simd()
{   /* TODO: detect neon for !MINIMP3_ONLY_SIMD */
    return 1;
}
#else
#define HAVE_SIMD 0
#ifdef MINIMP3_ONLY_SIMD
#error MINIMP3_ONLY_SIMD used, but SSE/NEON not enabled
#endif
#endif

#else

#define HAVE_SIMD 0

#endif

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

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

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

typedef struct
{
    const uint8_t *sfbtab;
    uint16_t part_23_length, big_values, scalefac_compress;
    uint8_t global_gain, block_type, mixed_block_flag, n_long_sfb, n_short_sfb;
    uint8_t table_select[3], region_count[3], subblock_gain[3];
    uint8_t preflag, scalefac_scale, count1_table, 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], scf[40], syn[18 + 15][2*32];
    uint8_t ist_pos[2][39];
} 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);
    if ((bs->pos += n) > bs->limit)
        return 0;
    next = *p++ & (255 >> s);
    while ((shl -= 8) > 0)
    {
        cache |= next << shl;
        next = *p++;
    }
    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_LAYER(h) != 0) &&
        (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)] >> (int)!HDR_TEST_MPEG1(h) >> (int)!HDR_TEST_NOT_MPEG25(h);
}

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

#ifndef MINIMP3_ONLY_MP3
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) >> (int)(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)MINIMP3_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];
        }
    }
}
#endif

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[8][23] = {
        { 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[8][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 },
        { 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[8][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 },
        { 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); sr_idx -= (sr_idx != 0);
    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 *= 2)
    {
        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(float y, int exp_q2)
{
    static const float g_expfrac[4] = { 9.31322575e-10f,7.83145814e-10f,6.58544508e-10f,5.53767716e-10f };
    int e;
    do
    {
        e = MINIMP3_MIN(30*4, exp_q2);
        y *= g_expfrac[e & 3]*(1 << 30 >> (e >> 2));
    } while ((exp_q2 -= e) > 0);
    return y;
}

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 = L3_ldexp_q2(1 << (MAX_SCFI/4),  MAX_SCFI - gain_exp);
    for (i = 0; i < (int)(gr->n_long_sfb + gr->n_short_sfb); i++)
    {
        scf[i] = L3_ldexp_q2(gain, iscf[i] << scf_shift);
    }
}

static const float g_pow43[129 + 16] = {
    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,
    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
};

static float L3_pow_43(int x)
{
    float frac;
    int sign, mult = 256;

    if (x < 129)
    {
        return g_pow43[16 + x];
    }

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

    sign = 2*x & 64;
    frac = (float)((x & 63) - sign) / ((x & ~63) + sign);
    return g_pow43[16 + ((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 int16_t tabs[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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,
        -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 tabindex[2*16] = { 0,32,64,98,0,132,180,218,292,364,426,538,648,746,0,1126,1460,1460,1460,1460,1460,1460,1460,1460,1842,1842,1842,1842,1842,1842,1842,1842 };
    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 = 0.0f;
    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]*256u + bs_next_ptr[1])*256u + bs_next_ptr[2])*256u + 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 = tabs + tabindex[tab_num];
        int linbits = g_linbits[tab_num];
        do
        {
            np = *sfb++ / 2;
            pairs_to_decode = MINIMP3_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 == 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[16 + lsb - 16*(bs_cache >> 31)]*one;
                    }
                    FLUSH_BITS(lsb ? 1 : 0);
                }
                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(1, (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] = MINIMP3_MAX(MINIMP3_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
#ifndef MINIMP3_ONLY_SIMD
        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];
        }
#endif
    }
}

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 = MINIMP3_MIN(h->reserv, main_data_begin);
    memcpy(s->maindata, h->reserv_buf + MINIMP3_MAX(0, h->reserv - main_data_begin), MINIMP3_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) << (int)(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 *)(void*)&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
#ifdef MINIMP3_ONLY_SIMD
    {}
#else
    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];
    }
#endif
}

static float mp3d_scale_pcm(float sample)
{
    return sample / 32768.0f;
}

static void mp3d_synth_pair(float *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, float *dstl, int nch, float *lins)
{
    int i;
    float *xr = xl + 576*(nch - 1);
    float *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)

        {
            static const f4 g_scale = { 1.0f/32768.0f, 1.0f/32768.0f, 1.0f/32768.0f, 1.0f/32768.0f };
            a = VMUL(a, g_scale);
            b = VMUL(b, g_scale);

#if HAVE_SSE
            _mm_store_ss(dstr + (15 - i)*nch, _mm_shuffle_ps(a, a, _MM_SHUFFLE(1, 1, 1, 1)));
            _mm_store_ss(dstr + (17 + i)*nch, _mm_shuffle_ps(b, b, _MM_SHUFFLE(1, 1, 1, 1)));
            _mm_store_ss(dstl + (15 - i)*nch, _mm_shuffle_ps(a, a, _MM_SHUFFLE(0, 0, 0, 0)));
            _mm_store_ss(dstl + (17 + i)*nch, _mm_shuffle_ps(b, b, _MM_SHUFFLE(0, 0, 0, 0)));
            _mm_store_ss(dstr + (47 - i)*nch, _mm_shuffle_ps(a, a, _MM_SHUFFLE(3, 3, 3, 3)));
            _mm_store_ss(dstr + (49 + i)*nch, _mm_shuffle_ps(b, b, _MM_SHUFFLE(3, 3, 3, 3)));
            _mm_store_ss(dstl + (47 - i)*nch, _mm_shuffle_ps(a, a, _MM_SHUFFLE(2, 2, 2, 2)));
            _mm_store_ss(dstl + (49 + i)*nch, _mm_shuffle_ps(b, b, _MM_SHUFFLE(2, 2, 2, 2)));
#else
            vst1q_lane_f32(dstr + (15 - i)*nch, a, 1);
            vst1q_lane_f32(dstr + (17 + i)*nch, b, 1);
            vst1q_lane_f32(dstl + (15 - i)*nch, a, 0);
            vst1q_lane_f32(dstl + (17 + i)*nch, b, 0);
            vst1q_lane_f32(dstr + (47 - i)*nch, a, 3);
            vst1q_lane_f32(dstr + (49 + i)*nch, b, 3);
            vst1q_lane_f32(dstl + (47 - i)*nch, a, 2);
            vst1q_lane_f32(dstl + (49 + i)*nch, b, 2);
#endif
        }
    } else
#endif
#ifdef MINIMP3_ONLY_SIMD
    {}
#else
    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]);
    }
#endif
}

static void mp3d_synth_granule(float *qmf_state, float *grbuf, int nbands, int nch, float *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);
    }
#ifndef MINIMP3_NONSTANDARD_BUT_LOGICAL
    if (nch == 1)
    {
        for (i = 0; i < 15*64; i += 2)
        {
            qmf_state[i] = lins[nbands*64 + i];
        }
    } else
#endif
    {
        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, mp3_bytes - i, frame_bytes)) ||
                (!i && frame_and_padding == mp3_bytes))
            {
                *ptr_frame_bytes = frame_and_padding;
                return i;
            }
            *free_format_bytes = 0;
        }
    }
    *ptr_frame_bytes = 0;
    return i;
}

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

int mp3dec_decode_frame(mp3dec_t *dec, const uint8_t *mp3, int mp3_bytes, float *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 (mp3_bytes > 4 && 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);

    if (!pcm)
    {
        return hdr_frame_samples(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 || bs_frame->pos > bs_frame->limit)
        {
            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
    {
#ifdef MINIMP3_ONLY_MP3
        return 0;
#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;
            }
        }
#endif
    }
    return success*hdr_frame_samples(dec->header);
}

int mp3dec_decode_frame_s16(mp3dec_t *dec, const uint8_t *mp3, int mp3_bytes, short *pcm, mp3dec_frame_info_t *info)
{
    if(pcm)
    {
        float temps[MINIMP3_MAX_SAMPLES_PER_FRAME];
        int samples_got;

        samples_got = mp3dec_decode_frame(dec, mp3, mp3_bytes, temps, info);
        if(samples_got > 0)
        {
            int todo = samples_got * info->channels;
            int i;

            for(i = 0;i < todo;i++)
            {
                float sample = temps[i]*32768.0f;
                short s = 0;
                if(sample <= -32767.5f)
                    s = -32768;
                else if(sample >= 32766.5f)
                    s = 32767;
                else
                {
                    s = (short)(sample + 0.5f);
                    s += s>>15;
                }

                *(pcm++) = s;
            }
        }

        return samples_got;
    }

    return mp3dec_decode_frame(dec, mp3, mp3_bytes, NULL, info);
}

#endif /*MINIMP3_IMPLEMENTATION*/
#endif /*MINIMP3_H*/