ps.c

/*
 * MPEG-4 Parametric Stereo decoding functions
 * Copyright (c) 2010 Alex Converse <alex.converse@gmail.com>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>
#include "libavutil/mathematics.h"
#include "avcodec.h"
#include "get_bits.h"
#include "ps.h"
#include "ps_tablegen.h"
#include "psdata.c"

#define PS_BASELINE 0  //< Operate in Baseline PS mode
                       //< Baseline implies 10 or 20 stereo bands,
                       //< mixing mode A, and no ipd/opd

#define numQMFSlots 32 //numTimeSlots * RATE

static const int8_t num_env_tab[2][4] = {
    { 0, 1, 2, 4, },
    { 1, 2, 3, 4, },
};

static const int8_t nr_iidicc_par_tab[] = {
    10, 20, 34, 10, 20, 34,
};

static const int8_t nr_iidopd_par_tab[] = {
     5, 11, 17,  5, 11, 17,
};

enum {
    huff_iid_df1,
    huff_iid_dt1,
    huff_iid_df0,
    huff_iid_dt0,
    huff_icc_df,
    huff_icc_dt,
    huff_ipd_df,
    huff_ipd_dt,
    huff_opd_df,
    huff_opd_dt,
};

static const int huff_iid[] = {
    huff_iid_df0,
    huff_iid_df1,
    huff_iid_dt0,
    huff_iid_dt1,
};

static VLC vlc_ps[10];

/**
 * Read Inter-channel Intensity Difference/Inter-Channel Coherence/
 * Inter-channel Phase Difference/Overall Phase Difference parameters from the
 * bitstream.
 *
 * @param avctx contains the current codec context
 * @param gb    pointer to the input bitstream
 * @param ps    pointer to the Parametric Stereo context
 * @param par   pointer to the parameter to be read
 * @param e     envelope to decode
 * @param dt    1: time delta-coded, 0: frequency delta-coded
 */
#define READ_PAR_DATA(PAR, OFFSET, MASK, ERR_CONDITION) \
static int PAR ## _data(AVCodecContext *avctx, GetBitContext *gb, PSContext *ps, \
                        int8_t (*PAR)[PS_MAX_NR_IIDICC], int table_idx, int e, int dt) \
{ \
    int b, num = ps->nr_ ## PAR ## _par; \
    VLC_TYPE (*vlc_table)[2] = vlc_ps[table_idx].table; \
    if (dt) { \
        int e_prev = e ? e - 1 : ps->num_env_old - 1; \
        e_prev = FFMAX(e_prev, 0); \
        for (b = 0; b < num; b++) { \
            int val = PAR[e_prev][b] + get_vlc2(gb, vlc_table, 9, 3) - OFFSET; \
            if (MASK) val &= MASK; \
            PAR[e][b] = val; \
            if (ERR_CONDITION) \
                goto err; \
        } \
    } else { \
        int val = 0; \
        for (b = 0; b < num; b++) { \
            val += get_vlc2(gb, vlc_table, 9, 3) - OFFSET; \
            if (MASK) val &= MASK; \
            PAR[e][b] = val; \
            if (ERR_CONDITION) \
                goto err; \
        } \
    } \
    return 0; \
err: \
    av_log(avctx, AV_LOG_ERROR, "illegal "#PAR"\n"); \
    return -1; \
}

READ_PAR_DATA(iid,    huff_offset[table_idx],    0, FFABS(ps->iid_par[e][b]) > 7 + 8 * ps->iid_quant)
READ_PAR_DATA(icc,    huff_offset[table_idx],    0, ps->icc_par[e][b] > 7U)
READ_PAR_DATA(ipdopd,                      0, 0x07, 0)

static int ps_extension(GetBitContext *gb, PSContext *ps, int ps_extension_id)
{
    int e;
    int count = get_bits_count(gb);

    if (ps_extension_id)
        return 0;

    ps->enable_ipdopd = get_bits1(gb);
    if (ps->enable_ipdopd) {
        for (e = 0; e < ps->num_env; e++) {
            int dt = get_bits1(gb);
            ipdopd_data(NULL, gb, ps, ps->ipd_par, dt ? huff_ipd_dt : huff_ipd_df, e, dt);
            dt = get_bits1(gb);
            ipdopd_data(NULL, gb, ps, ps->opd_par, dt ? huff_opd_dt : huff_opd_df, e, dt);
        }
    }
    skip_bits1(gb);      //reserved_ps
    return get_bits_count(gb) - count;
}

static void ipdopd_reset(int8_t *opd_hist, int8_t *ipd_hist)
{
    int i;
    for (i = 0; i < PS_MAX_NR_IPDOPD; i++) {
        opd_hist[i] = 0;
        ipd_hist[i] = 0;
    }
}

int ff_ps_read_data(AVCodecContext *avctx, GetBitContext *gb_host, PSContext *ps, int bits_left)
{
    int e;
    int bit_count_start = get_bits_count(gb_host);
    int header;
    int bits_consumed;
    GetBitContext gbc = *gb_host, *gb = &gbc;

    header = get_bits1(gb);
    if (header) {     //enable_ps_header
        ps->enable_iid = get_bits1(gb);
        if (ps->enable_iid) {
            int iid_mode = get_bits(gb, 3);
            if (iid_mode > 5) {
                av_log(avctx, AV_LOG_ERROR, "iid_mode %d is reserved.\n",
                       iid_mode);
                goto err;
            }
            ps->nr_iid_par    = nr_iidicc_par_tab[iid_mode];
            ps->iid_quant     = iid_mode > 2;
            ps->nr_ipdopd_par = nr_iidopd_par_tab[iid_mode];
        }
        ps->enable_icc = get_bits1(gb);
        if (ps->enable_icc) {
            ps->icc_mode = get_bits(gb, 3);
            if (ps->icc_mode > 5) {
                av_log(avctx, AV_LOG_ERROR, "icc_mode %d is reserved.\n",
                       ps->icc_mode);
                goto err;
            }
            ps->nr_icc_par = nr_iidicc_par_tab[ps->icc_mode];
        }
        ps->enable_ext = get_bits1(gb);
    }

    ps->frame_class = get_bits1(gb);
    ps->num_env_old = ps->num_env;
    ps->num_env     = num_env_tab[ps->frame_class][get_bits(gb, 2)];

    ps->border_position[0] = -1;
    if (ps->frame_class) {
        for (e = 1; e <= ps->num_env; e++)
            ps->border_position[e] = get_bits(gb, 5);
    } else
        for (e = 1; e <= ps->num_env; e++)
            ps->border_position[e] = e * numQMFSlots / ps->num_env - 1;

    if (ps->enable_iid) {
        for (e = 0; e < ps->num_env; e++) {
            int dt = get_bits1(gb);
            if (iid_data(avctx, gb, ps, ps->iid_par, huff_iid[2*dt+ps->iid_quant], e, dt))
                goto err;
        }
    } else
        memset(ps->iid_par, 0, sizeof(ps->iid_par));

    if (ps->enable_icc)
        for (e = 0; e < ps->num_env; e++) {
            int dt = get_bits1(gb);
            if (icc_data(avctx, gb, ps, ps->icc_par, dt ? huff_icc_dt : huff_icc_df, e, dt))
                goto err;
        }
    else
        memset(ps->icc_par, 0, sizeof(ps->icc_par));

    if (ps->enable_ext) {
        int cnt = get_bits(gb, 4);
        if (cnt == 15) {
            cnt += get_bits(gb, 8);
        }
        cnt *= 8;
        while (cnt > 7) {
            int ps_extension_id = get_bits(gb, 2);
            cnt -= 2 + ps_extension(gb, ps, ps_extension_id);
        }
        if (cnt < 0) {
            av_log(avctx, AV_LOG_ERROR, "ps extension overflow %d", cnt);
            goto err;
        }
        skip_bits(gb, cnt);
    }

    ps->enable_ipdopd &= !PS_BASELINE;

    //Fix up envelopes
    if (!ps->num_env || ps->border_position[ps->num_env] < numQMFSlots - 1) {
        //Create a fake envelope
        int source = ps->num_env ? ps->num_env - 1 : ps->num_env_old - 1;
        if (source >= 0 && source != ps->num_env) {
            if (ps->enable_iid) {
                memcpy(ps->iid_par+ps->num_env, ps->iid_par+source, sizeof(ps->iid_par[0]));
            }
            if (ps->enable_icc) {
                memcpy(ps->icc_par+ps->num_env, ps->icc_par+source, sizeof(ps->icc_par[0]));
            }
            if (ps->enable_ipdopd) {
                memcpy(ps->ipd_par+ps->num_env, ps->ipd_par+source, sizeof(ps->ipd_par[0]));
                memcpy(ps->opd_par+ps->num_env, ps->opd_par+source, sizeof(ps->opd_par[0]));
            }
        }
        ps->num_env++;
        ps->border_position[ps->num_env] = numQMFSlots - 1;
    }


    ps->is34bands_old = ps->is34bands;
    if (!PS_BASELINE && (ps->enable_iid || ps->enable_icc))
        ps->is34bands = (ps->enable_iid && ps->nr_iid_par == 34) ||
                        (ps->enable_icc && ps->nr_icc_par == 34);

    //Baseline
    if (!ps->enable_ipdopd) {
        memset(ps->ipd_par, 0, sizeof(ps->ipd_par));
        memset(ps->opd_par, 0, sizeof(ps->opd_par));
    }

    if (header)
        ps->start = 1;

    bits_consumed = get_bits_count(gb) - bit_count_start;
    if (bits_consumed <= bits_left) {
        skip_bits_long(gb_host, bits_consumed);
        return bits_consumed;
    }
    av_log(avctx, AV_LOG_ERROR, "Expected to read %d PS bits actually read %d.\n", bits_left, bits_consumed);
err:
    ps->start = 0;
    skip_bits_long(gb_host, bits_left);
    return bits_left;
}

/** Split one subband into 2 subsubbands with a symmetric real filter.
 * The filter must have its non-center even coefficients equal to zero. */
static void hybrid2_re(float (*in)[2], float (*out)[32][2], const float filter[7], int len, int reverse)
{
    int i, j;
    for (i = 0; i < len; i++) {
        float re_in = filter[6] * in[6+i][0];        //real inphase
        float re_op = 0.0f;                          //real out of phase
        float im_in = filter[6] * in[6+i][1];        //imag inphase
        float im_op = 0.0f;                          //imag out of phase
        for (j = 0; j < 6; j += 2) {
            re_op += filter[j+1] * (in[i+j+1][0] + in[12-j-1+i][0]);
            im_op += filter[j+1] * (in[i+j+1][1] + in[12-j-1+i][1]);
        }
        out[ reverse][i][0] = re_in + re_op;
        out[ reverse][i][1] = im_in + im_op;
        out[!reverse][i][0] = re_in - re_op;
        out[!reverse][i][1] = im_in - im_op;
    }
}

/** Split one subband into 6 subsubbands with a complex filter */
static void hybrid6_cx(float (*in)[2], float (*out)[32][2], const float (*filter)[7][2], int len)
{
    int i, j, ssb;
    int N = 8;
    float temp[8][2];

    for (i = 0; i < len; i++) {
        for (ssb = 0; ssb < N; ssb++) {
            float sum_re = filter[ssb][6][0] * in[i+6][0], sum_im = filter[ssb][6][0] * in[i+6][1];
            for (j = 0; j < 6; j++) {
                float in0_re = in[i+j][0];
                float in0_im = in[i+j][1];
                float in1_re = in[i+12-j][0];
                float in1_im = in[i+12-j][1];
                sum_re += filter[ssb][j][0] * (in0_re + in1_re) - filter[ssb][j][1] * (in0_im - in1_im);
                sum_im += filter[ssb][j][0] * (in0_im + in1_im) + filter[ssb][j][1] * (in0_re - in1_re);
            }
            temp[ssb][0] = sum_re;
            temp[ssb][1] = sum_im;
        }
        out[0][i][0] = temp[6][0];
        out[0][i][1] = temp[6][1];
        out[1][i][0] = temp[7][0];
        out[1][i][1] = temp[7][1];
        out[2][i][0] = temp[0][0];
        out[2][i][1] = temp[0][1];
        out[3][i][0] = temp[1][0];
        out[3][i][1] = temp[1][1];
        out[4][i][0] = temp[2][0] + temp[5][0];
        out[4][i][1] = temp[2][1] + temp[5][1];
        out[5][i][0] = temp[3][0] + temp[4][0];
        out[5][i][1] = temp[3][1] + temp[4][1];
    }
}

static void hybrid4_8_12_cx(float (*in)[2], float (*out)[32][2], const float (*filter)[7][2], int N, int len)
{
    int i, j, ssb;

    for (i = 0; i < len; i++) {
        for (ssb = 0; ssb < N; ssb++) {
            float sum_re = filter[ssb][6][0] * in[i+6][0], sum_im = filter[ssb][6][0] * in[i+6][1];
            for (j = 0; j < 6; j++) {
                float in0_re = in[i+j][0];
                float in0_im = in[i+j][1];
                float in1_re = in[i+12-j][0];
                float in1_im = in[i+12-j][1];
                sum_re += filter[ssb][j][0] * (in0_re + in1_re) - filter[ssb][j][1] * (in0_im - in1_im);
                sum_im += filter[ssb][j][0] * (in0_im + in1_im) + filter[ssb][j][1] * (in0_re - in1_re);
            }
            out[ssb][i][0] = sum_re;
            out[ssb][i][1] = sum_im;
        }
    }
}

static void hybrid_analysis(float out[91][32][2], float in[5][44][2], float L[2][38][64], int is34, int len)
{
    int i, j;
    for (i = 0; i < 5; i++) {
        for (j = 0; j < 38; j++) {
            in[i][j+6][0] = L[0][j][i];
            in[i][j+6][1] = L[1][j][i];
        }
    }
    if(is34) {
        hybrid4_8_12_cx(in[0], out,    f34_0_12, 12, len);
        hybrid4_8_12_cx(in[1], out+12, f34_1_8,   8, len);
        hybrid4_8_12_cx(in[2], out+20, f34_2_4,   4, len);
        hybrid4_8_12_cx(in[3], out+24, f34_2_4,   4, len);
        hybrid4_8_12_cx(in[4], out+28, f34_2_4,   4, len);
        for (i = 0; i < 59; i++) {
            for (j = 0; j < len; j++) {
                out[i+32][j][0] = L[0][j][i+5];
                out[i+32][j][1] = L[1][j][i+5];
            }
        }
    } else {
        hybrid6_cx(in[0], out, f20_0_8, len);
        hybrid2_re(in[1], out+6, g1_Q2, len, 1);
        hybrid2_re(in[2], out+8, g1_Q2, len, 0);
        for (i = 0; i < 61; i++) {
            for (j = 0; j < len; j++) {
                out[i+10][j][0] = L[0][j][i+3];
                out[i+10][j][1] = L[1][j][i+3];
            }
        }
    }
    //update in_buf
    for (i = 0; i < 5; i++) {
        memcpy(in[i], in[i]+32, 6 * sizeof(in[i][0]));
    }
}

static void hybrid_synthesis(float out[2][38][64], float in[91][32][2], int is34, int len)
{
    int i, n;
    if(is34) {
        for (n = 0; n < len; n++) {
            memset(out[0][n], 0, 5*sizeof(out[0][n][0]));
            memset(out[1][n], 0, 5*sizeof(out[1][n][0]));
            for(i = 0; i < 12; i++) {
                out[0][n][0] += in[   i][n][0];
                out[1][n][0] += in[   i][n][1];
            }
            for(i = 0; i < 8; i++) {
                out[0][n][1] += in[12+i][n][0];
                out[1][n][1] += in[12+i][n][1];
            }
            for(i = 0; i < 4; i++) {
                out[0][n][2] += in[20+i][n][0];
                out[1][n][2] += in[20+i][n][1];
                out[0][n][3] += in[24+i][n][0];
                out[1][n][3] += in[24+i][n][1];
                out[0][n][4] += in[28+i][n][0];
                out[1][n][4] += in[28+i][n][1];
            }
        }
        for (i = 0; i < 59; i++) {
            for (n = 0; n < len; n++) {
                out[0][n][i+5] = in[i+32][n][0];
                out[1][n][i+5] = in[i+32][n][1];
            }
        }
    } else {
        for (n = 0; n < len; n++) {
            out[0][n][0] = in[0][n][0] + in[1][n][0] + in[2][n][0] +
                           in[3][n][0] + in[4][n][0] + in[5][n][0];
            out[1][n][0] = in[0][n][1] + in[1][n][1] + in[2][n][1] +
                           in[3][n][1] + in[4][n][1] + in[5][n][1];
            out[0][n][1] = in[6][n][0] + in[7][n][0];
            out[1][n][1] = in[6][n][1] + in[7][n][1];
            out[0][n][2] = in[8][n][0] + in[9][n][0];
            out[1][n][2] = in[8][n][1] + in[9][n][1];
        }
        for (i = 0; i < 61; i++) {
            for (n = 0; n < len; n++) {
                out[0][n][i+3] = in[i+10][n][0];
                out[1][n][i+3] = in[i+10][n][1];
            }
        }
    }
}

/// All-pass filter decay slope
#define DECAY_SLOPE      0.05f
/// Number of frequency bands that can be addressed by the parameter index, b(k)
static const int   NR_PAR_BANDS[]      = { 20, 34 };
/// Number of frequency bands that can be addressed by the sub subband index, k
static const int   NR_BANDS[]          = { 71, 91 };
/// Start frequency band for the all-pass filter decay slope
static const int   DECAY_CUTOFF[]      = { 10, 32 };
/// Number of all-pass filer bands
static const int   NR_ALLPASS_BANDS[]  = { 30, 50 };
/// First stereo band using the short one sample delay
static const int   SHORT_DELAY_BAND[]  = { 42, 62 };

/** Table 8.46 */
static void map_idx_10_to_20(int8_t *par_mapped, const int8_t *par, int full)
{
    int b;
    if (full)
        b = 9;
    else {
        b = 4;
        par_mapped[10] = 0;
    }
    for (; b >= 0; b--) {
        par_mapped[2*b+1] = par_mapped[2*b] = par[b];
    }
}

static void map_idx_34_to_20(int8_t *par_mapped, const int8_t *par, int full)
{
    par_mapped[ 0] = (2*par[ 0] +   par[ 1]) / 3;
    par_mapped[ 1] = (  par[ 1] + 2*par[ 2]) / 3;
    par_mapped[ 2] = (2*par[ 3] +   par[ 4]) / 3;
    par_mapped[ 3] = (  par[ 4] + 2*par[ 5]) / 3;
    par_mapped[ 4] = (  par[ 6] +   par[ 7]) / 2;
    par_mapped[ 5] = (  par[ 8] +   par[ 9]) / 2;
    par_mapped[ 6] =    par[10];
    par_mapped[ 7] =    par[11];
    par_mapped[ 8] = (  par[12] +   par[13]) / 2;
    par_mapped[ 9] = (  par[14] +   par[15]) / 2;
    par_mapped[10] =    par[16];
    if (full) {
        par_mapped[11] =    par[17];
        par_mapped[12] =    par[18];
        par_mapped[13] =    par[19];
        par_mapped[14] = (  par[20] +   par[21]) / 2;
        par_mapped[15] = (  par[22] +   par[23]) / 2;
        par_mapped[16] = (  par[24] +   par[25]) / 2;
        par_mapped[17] = (  par[26] +   par[27]) / 2;
        par_mapped[18] = (  par[28] +   par[29] +   par[30] +   par[31]) / 4;
        par_mapped[19] = (  par[32] +   par[33]) / 2;
    }
}

static void map_val_34_to_20(float par[PS_MAX_NR_IIDICC])
{
    par[ 0] = (2*par[ 0] +   par[ 1]) * 0.33333333f;
    par[ 1] = (  par[ 1] + 2*par[ 2]) * 0.33333333f;
    par[ 2] = (2*par[ 3] +   par[ 4]) * 0.33333333f;
    par[ 3] = (  par[ 4] + 2*par[ 5]) * 0.33333333f;
    par[ 4] = (  par[ 6] +   par[ 7]) * 0.5f;
    par[ 5] = (  par[ 8] +   par[ 9]) * 0.5f;
    par[ 6] =    par[10];
    par[ 7] =    par[11];
    par[ 8] = (  par[12] +   par[13]) * 0.5f;
    par[ 9] = (  par[14] +   par[15]) * 0.5f;
    par[10] =    par[16];
    par[11] =    par[17];
    par[12] =    par[18];
    par[13] =    par[19];
    par[14] = (  par[20] +   par[21]) * 0.5f;
    par[15] = (  par[22] +   par[23]) * 0.5f;
    par[16] = (  par[24] +   par[25]) * 0.5f;
    par[17] = (  par[26] +   par[27]) * 0.5f;
    par[18] = (  par[28] +   par[29] +   par[30] +   par[31]) * 0.25f;
    par[19] = (  par[32] +   par[33]) * 0.5f;
}

static void map_idx_10_to_34(int8_t *par_mapped, const int8_t *par, int full)
{
    if (full) {
        par_mapped[33] = par[9];
        par_mapped[32] = par[9];
        par_mapped[31] = par[9];
        par_mapped[30] = par[9];
        par_mapped[29] = par[9];
        par_mapped[28] = par[9];
        par_mapped[27] = par[8];
        par_mapped[26] = par[8];
        par_mapped[25] = par[8];
        par_mapped[24] = par[8];
        par_mapped[23] = par[7];
        par_mapped[22] = par[7];
        par_mapped[21] = par[7];
        par_mapped[20] = par[7];
        par_mapped[19] = par[6];
        par_mapped[18] = par[6];
        par_mapped[17] = par[5];
        par_mapped[16] = par[5];
    } else {
        par_mapped[16] =      0;
    }
    par_mapped[15] = par[4];
    par_mapped[14] = par[4];
    par_mapped[13] = par[4];
    par_mapped[12] = par[4];
    par_mapped[11] = par[3];
    par_mapped[10] = par[3];
    par_mapped[ 9] = par[2];
    par_mapped[ 8] = par[2];
    par_mapped[ 7] = par[2];
    par_mapped[ 6] = par[2];
    par_mapped[ 5] = par[1];
    par_mapped[ 4] = par[1];
    par_mapped[ 3] = par[1];
    par_mapped[ 2] = par[0];
    par_mapped[ 1] = par[0];
    par_mapped[ 0] = par[0];
}

static void map_idx_20_to_34(int8_t *par_mapped, const int8_t *par, int full)
{
    if (full) {
        par_mapped[33] =  par[19];
        par_mapped[32] =  par[19];
        par_mapped[31] =  par[18];
        par_mapped[30] =  par[18];
        par_mapped[29] =  par[18];
        par_mapped[28] =  par[18];
        par_mapped[27] =  par[17];
        par_mapped[26] =  par[17];
        par_mapped[25] =  par[16];
        par_mapped[24] =  par[16];
        par_mapped[23] =  par[15];
        par_mapped[22] =  par[15];
        par_mapped[21] =  par[14];
        par_mapped[20] =  par[14];
        par_mapped[19] =  par[13];
        par_mapped[18] =  par[12];
        par_mapped[17] =  par[11];
    }
    par_mapped[16] =  par[10];
    par_mapped[15] =  par[ 9];
    par_mapped[14] =  par[ 9];
    par_mapped[13] =  par[ 8];
    par_mapped[12] =  par[ 8];
    par_mapped[11] =  par[ 7];
    par_mapped[10] =  par[ 6];
    par_mapped[ 9] =  par[ 5];
    par_mapped[ 8] =  par[ 5];
    par_mapped[ 7] =  par[ 4];
    par_mapped[ 6] =  par[ 4];
    par_mapped[ 5] =  par[ 3];
    par_mapped[ 4] = (par[ 2] + par[ 3]) / 2;
    par_mapped[ 3] =  par[ 2];
    par_mapped[ 2] =  par[ 1];
    par_mapped[ 1] = (par[ 0] + par[ 1]) / 2;
    par_mapped[ 0] =  par[ 0];
}

static void map_val_20_to_34(float par[PS_MAX_NR_IIDICC])
{
    par[33] =  par[19];
    par[32] =  par[19];
    par[31] =  par[18];
    par[30] =  par[18];
    par[29] =  par[18];
    par[28] =  par[18];
    par[27] =  par[17];
    par[26] =  par[17];
    par[25] =  par[16];
    par[24] =  par[16];
    par[23] =  par[15];
    par[22] =  par[15];
    par[21] =  par[14];
    par[20] =  par[14];
    par[19] =  par[13];
    par[18] =  par[12];
    par[17] =  par[11];
    par[16] =  par[10];
    par[15] =  par[ 9];
    par[14] =  par[ 9];
    par[13] =  par[ 8];
    par[12] =  par[ 8];
    par[11] =  par[ 7];
    par[10] =  par[ 6];
    par[ 9] =  par[ 5];
    par[ 8] =  par[ 5];
    par[ 7] =  par[ 4];
    par[ 6] =  par[ 4];
    par[ 5] =  par[ 3];
    par[ 4] = (par[ 2] + par[ 3]) * 0.5f;
    par[ 3] =  par[ 2];
    par[ 2] =  par[ 1];
    par[ 1] = (par[ 0] + par[ 1]) * 0.5f;
    par[ 0] =  par[ 0];
}

static void decorrelation(PSContext *ps, float (*out)[32][2], const float (*s)[32][2], int is34)
{
    float power[34][PS_QMF_TIME_SLOTS] = {{0}};
    float transient_gain[34][PS_QMF_TIME_SLOTS];
    float *peak_decay_nrg = ps->peak_decay_nrg;
    float *power_smooth = ps->power_smooth;
    float *peak_decay_diff_smooth = ps->peak_decay_diff_smooth;
    float (*delay)[PS_QMF_TIME_SLOTS + PS_MAX_DELAY][2] = ps->delay;
    float (*ap_delay)[PS_AP_LINKS][PS_QMF_TIME_SLOTS + PS_MAX_AP_DELAY][2] = ps->ap_delay;
    const int8_t *k_to_i = is34 ? k_to_i_34 : k_to_i_20;
    const float peak_decay_factor = 0.76592833836465f;
    const float transient_impact  = 1.5f;
    const float a_smooth          = 0.25f; //< Smoothing coefficient
    int i, k, m, n;
    int n0 = 0, nL = 32;
    static const int link_delay[] = { 3, 4, 5 };
    static const float a[] = { 0.65143905753106f,
                               0.56471812200776f,
                               0.48954165955695f };

    if (is34 != ps->is34bands_old) {
        memset(ps->peak_decay_nrg,         0, sizeof(ps->peak_decay_nrg));
        memset(ps->power_smooth,           0, sizeof(ps->power_smooth));
        memset(ps->peak_decay_diff_smooth, 0, sizeof(ps->peak_decay_diff_smooth));
        memset(ps->delay,                  0, sizeof(ps->delay));
        memset(ps->ap_delay,               0, sizeof(ps->ap_delay));
    }

    for (n = n0; n < nL; n++) {
        for (k = 0; k < NR_BANDS[is34]; k++) {
            int i = k_to_i[k];
            power[i][n] += s[k][n][0] * s[k][n][0] + s[k][n][1] * s[k][n][1];
        }
    }

    //Transient detection
    for (i = 0; i < NR_PAR_BANDS[is34]; i++) {
        for (n = n0; n < nL; n++) {
            float decayed_peak = peak_decay_factor * peak_decay_nrg[i];
            float denom;
            peak_decay_nrg[i] = FFMAX(decayed_peak, power[i][n]);
            power_smooth[i] += a_smooth * (power[i][n] - power_smooth[i]);
            peak_decay_diff_smooth[i] += a_smooth * (peak_decay_nrg[i] - power[i][n] - peak_decay_diff_smooth[i]);
            denom = transient_impact * peak_decay_diff_smooth[i];
            transient_gain[i][n]   = (denom > power_smooth[i]) ?
                                         power_smooth[i] / denom : 1.0f;
        }
    }

    //Decorrelation and transient reduction
    //                         PS_AP_LINKS - 1
    //                               -----
    //                                | |  Q_fract_allpass[k][m]*z^-link_delay[m] - a[m]*g_decay_slope[k]
    //H[k][z] = z^-2 * phi_fract[k] * | | ----------------------------------------------------------------
    //                                | | 1 - a[m]*g_decay_slope[k]*Q_fract_allpass[k][m]*z^-link_delay[m]
    //                               m = 0
    //d[k][z] (out) = transient_gain_mapped[k][z] * H[k][z] * s[k][z]
    for (k = 0; k < NR_ALLPASS_BANDS[is34]; k++) {
        int b = k_to_i[k];
        float g_decay_slope = 1.f - DECAY_SLOPE * (k - DECAY_CUTOFF[is34]);
        float ag[PS_AP_LINKS];
        g_decay_slope = av_clipf(g_decay_slope, 0.f, 1.f);
        memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0]));
        memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0]));
        for (m = 0; m < PS_AP_LINKS; m++) {
            memcpy(ap_delay[k][m],   ap_delay[k][m]+numQMFSlots,           5*sizeof(ap_delay[k][m][0]));
            ag[m] = a[m] * g_decay_slope;
        }
        for (n = n0; n < nL; n++) {
            float in_re = delay[k][n+PS_MAX_DELAY-2][0] * phi_fract[is34][k][0] -
                          delay[k][n+PS_MAX_DELAY-2][1] * phi_fract[is34][k][1];
            float in_im = delay[k][n+PS_MAX_DELAY-2][0] * phi_fract[is34][k][1] +
                          delay[k][n+PS_MAX_DELAY-2][1] * phi_fract[is34][k][0];
            for (m = 0; m < PS_AP_LINKS; m++) {
                float a_re                = ag[m] * in_re;
                float a_im                = ag[m] * in_im;
                float link_delay_re       = ap_delay[k][m][n+5-link_delay[m]][0];
                float link_delay_im       = ap_delay[k][m][n+5-link_delay[m]][1];
                float fractional_delay_re = Q_fract_allpass[is34][k][m][0];
                float fractional_delay_im = Q_fract_allpass[is34][k][m][1];
                ap_delay[k][m][n+5][0] = in_re;
                ap_delay[k][m][n+5][1] = in_im;
                in_re = link_delay_re * fractional_delay_re - link_delay_im * fractional_delay_im - a_re;
                in_im = link_delay_re * fractional_delay_im + link_delay_im * fractional_delay_re - a_im;
                ap_delay[k][m][n+5][0] += ag[m] * in_re;
                ap_delay[k][m][n+5][1] += ag[m] * in_im;
            }
            out[k][n][0] = transient_gain[b][n] * in_re;
            out[k][n][1] = transient_gain[b][n] * in_im;
        }
    }
    for (; k < SHORT_DELAY_BAND[is34]; k++) {
        memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0]));
        memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0]));
        for (n = n0; n < nL; n++) {
            //H = delay 14
            out[k][n][0] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-14][0];
            out[k][n][1] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-14][1];
        }
    }
    for (; k < NR_BANDS[is34]; k++) {
        memcpy(delay[k], delay[k]+nL, PS_MAX_DELAY*sizeof(delay[k][0]));
        memcpy(delay[k]+PS_MAX_DELAY, s[k], numQMFSlots*sizeof(delay[k][0]));
        for (n = n0; n < nL; n++) {
            //H = delay 1
            out[k][n][0] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-1][0];
            out[k][n][1] = transient_gain[k_to_i[k]][n] * delay[k][n+PS_MAX_DELAY-1][1];
        }
    }
}

static void remap34(int8_t (**p_par_mapped)[PS_MAX_NR_IIDICC],
                    int8_t           (*par)[PS_MAX_NR_IIDICC],
                    int num_par, int num_env, int full)
{
    int8_t (*par_mapped)[PS_MAX_NR_IIDICC] = *p_par_mapped;
    int e;
    if (num_par == 20 || num_par == 11) {
        for (e = 0; e < num_env; e++) {
            map_idx_20_to_34(par_mapped[e], par[e], full);
        }
    } else if (num_par == 10 || num_par == 5) {
        for (e = 0; e < num_env; e++) {
            map_idx_10_to_34(par_mapped[e], par[e], full);
        }
    } else {
        *p_par_mapped = par;
    }
}

static void remap20(int8_t (**p_par_mapped)[PS_MAX_NR_IIDICC],
                    int8_t           (*par)[PS_MAX_NR_IIDICC],
                    int num_par, int num_env, int full)
{
    int8_t (*par_mapped)[PS_MAX_NR_IIDICC] = *p_par_mapped;
    int e;
    if (num_par == 34 || num_par == 17) {
        for (e = 0; e < num_env; e++) {
            map_idx_34_to_20(par_mapped[e], par[e], full);
        }
    } else if (num_par == 10 || num_par == 5) {
        for (e = 0; e < num_env; e++) {
            map_idx_10_to_20(par_mapped[e], par[e], full);
        }
    } else {
        *p_par_mapped = par;
    }
}

static void stereo_processing(PSContext *ps, float (*l)[32][2], float (*r)[32][2], int is34)
{
    int e, b, k, n;

    float (*H11)[PS_MAX_NUM_ENV+1][PS_MAX_NR_IIDICC] = ps->H11;
    float (*H12)[PS_MAX_NUM_ENV+1][PS_MAX_NR_IIDICC] = ps->H12;
    float (*H21)[PS_MAX_NUM_ENV+1][PS_MAX_NR_IIDICC] = ps->H21;
    float (*H22)[PS_MAX_NUM_ENV+1][PS_MAX_NR_IIDICC] = ps->H22;
    int8_t *opd_hist = ps->opd_hist;
    int8_t *ipd_hist = ps->ipd_hist;
    int8_t iid_mapped_buf[PS_MAX_NUM_ENV][PS_MAX_NR_IIDICC];
    int8_t icc_mapped_buf[PS_MAX_NUM_ENV][PS_MAX_NR_IIDICC];
    int8_t ipd_mapped_buf[PS_MAX_NUM_ENV][PS_MAX_NR_IIDICC];
    int8_t opd_mapped_buf[PS_MAX_NUM_ENV][PS_MAX_NR_IIDICC];
    int8_t (*iid_mapped)[PS_MAX_NR_IIDICC] = iid_mapped_buf;
    int8_t (*icc_mapped)[PS_MAX_NR_IIDICC] = icc_mapped_buf;
    int8_t (*ipd_mapped)[PS_MAX_NR_IIDICC] = ipd_mapped_buf;
    int8_t (*opd_mapped)[PS_MAX_NR_IIDICC] = opd_mapped_buf;
    const int8_t *k_to_i = is34 ? k_to_i_34 : k_to_i_20;
    const float (*H_LUT)[8][4] = (PS_BASELINE || ps->icc_mode < 3) ? HA : HB;

    //Remapping
    memcpy(H11[0][0], H11[0][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H11[0][0][0]));
    memcpy(H11[1][0], H11[1][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H11[1][0][0]));
    memcpy(H12[0][0], H12[0][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H12[0][0][0]));
    memcpy(H12[1][0], H12[1][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H12[1][0][0]));
    memcpy(H21[0][0], H21[0][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H21[0][0][0]));
    memcpy(H21[1][0], H21[1][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H21[1][0][0]));
    memcpy(H22[0][0], H22[0][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H22[0][0][0]));
    memcpy(H22[1][0], H22[1][ps->num_env_old], PS_MAX_NR_IIDICC*sizeof(H22[1][0][0]));
    if (is34) {
        remap34(&iid_mapped, ps->iid_par, ps->nr_iid_par, ps->num_env, 1);
        remap34(&icc_mapped, ps->icc_par, ps->nr_icc_par, ps->num_env, 1);
        if (ps->enable_ipdopd) {
            remap34(&ipd_mapped, ps->ipd_par, ps->nr_ipdopd_par, ps->num_env, 0);
            remap34(&opd_mapped, ps->opd_par, ps->nr_ipdopd_par, ps->num_env, 0);
        }
        if (!ps->is34bands_old) {
            map_val_20_to_34(H11[0][0]);
            map_val_20_to_34(H11[1][0]);
            map_val_20_to_34(H12[0][0]);
            map_val_20_to_34(H12[1][0]);
            map_val_20_to_34(H21[0][0]);
            map_val_20_to_34(H21[1][0]);
            map_val_20_to_34(H22[0][0]);
            map_val_20_to_34(H22[1][0]);
            ipdopd_reset(ipd_hist, opd_hist);
        }
    } else {
        remap20(&iid_mapped, ps->iid_par, ps->nr_iid_par, ps->num_env, 1);
        remap20(&icc_mapped, ps->icc_par, ps->nr_icc_par, ps->num_env, 1);
        if (ps->enable_ipdopd) {
            remap20(&ipd_mapped, ps->ipd_par, ps->nr_ipdopd_par, ps->num_env, 0);
            remap20(&opd_mapped, ps->opd_par, ps->nr_ipdopd_par, ps->num_env, 0);
        }
        if (ps->is34bands_old) {
            map_val_34_to_20(H11[0][0]);
            map_val_34_to_20(H11[1][0]);
            map_val_34_to_20(H12[0][0]);
            map_val_34_to_20(H12[1][0]);
            map_val_34_to_20(H21[0][0]);
            map_val_34_to_20(H21[1][0]);
            map_val_34_to_20(H22[0][0]);
            map_val_34_to_20(H22[1][0]);
            ipdopd_reset(ipd_hist, opd_hist);
        }
    }

    //Mixing
    for (e = 0; e < ps->num_env; e++) {
        for (b = 0; b < NR_PAR_BANDS[is34]; b++) {
            float h11, h12, h21, h22;
            h11 = H_LUT[iid_mapped[e][b] + 7 + 23 * ps->iid_quant][icc_mapped[e][b]][0];
            h12 = H_LUT[iid_mapped[e][b] + 7 + 23 * ps->iid_quant][icc_mapped[e][b]][1];
            h21 = H_LUT[iid_mapped[e][b] + 7 + 23 * ps->iid_quant][icc_mapped[e][b]][2];
            h22 = H_LUT[iid_mapped[e][b] + 7 + 23 * ps->iid_quant][icc_mapped[e][b]][3];
            if (!PS_BASELINE && ps->enable_ipdopd && b < ps->nr_ipdopd_par) {
                //The spec say says to only run this smoother when enable_ipdopd
                //is set but the reference decoder appears to run it constantly
                float h11i, h12i, h21i, h22i;
                float ipd_adj_re, ipd_adj_im;
                int opd_idx = opd_hist[b] * 8 + opd_mapped[e][b];
                int ipd_idx = ipd_hist[b] * 8 + ipd_mapped[e][b];
                float opd_re = pd_re_smooth[opd_idx];
                float opd_im = pd_im_smooth[opd_idx];
                float ipd_re = pd_re_smooth[ipd_idx];
                float ipd_im = pd_im_smooth[ipd_idx];
                opd_hist[b] = opd_idx & 0x3F;
                ipd_hist[b] = ipd_idx & 0x3F;

                ipd_adj_re = opd_re*ipd_re + opd_im*ipd_im;
                ipd_adj_im = opd_im*ipd_re - opd_re*ipd_im;
                h11i = h11 * opd_im;
                h11  = h11 * opd_re;
                h12i = h12 * ipd_adj_im;
                h12  = h12 * ipd_adj_re;
                h21i = h21 * opd_im;
                h21  = h21 * opd_re;
                h22i = h22 * ipd_adj_im;
                h22  = h22 * ipd_adj_re;
                H11[1][e+1][b] = h11i;
                H12[1][e+1][b] = h12i;
                H21[1][e+1][b] = h21i;
                H22[1][e+1][b] = h22i;
            }
            H11[0][e+1][b] = h11;
            H12[0][e+1][b] = h12;
            H21[0][e+1][b] = h21;
            H22[0][e+1][b] = h22;
        }
        for (k = 0; k < NR_BANDS[is34]; k++) {
            float h11r, h12r, h21r, h22r;
            float h11i, h12i, h21i, h22i;
            float h11r_step, h12r_step, h21r_step, h22r_step;
            float h11i_step, h12i_step, h21i_step, h22i_step;
            int start = ps->border_position[e];
            int stop  = ps->border_position[e+1];
            float width = 1.f / (stop - start);
            b = k_to_i[k];
            h11r = H11[0][e][b];
            h12r = H12[0][e][b];
            h21r = H21[0][e][b];
            h22r = H22[0][e][b];
            if (!PS_BASELINE && ps->enable_ipdopd) {
            //Is this necessary? ps_04_new seems unchanged
            if ((is34 && k <= 13 && k >= 9) || (!is34 && k <= 1)) {
                h11i = -H11[1][e][b];
                h12i = -H12[1][e][b];
                h21i = -H21[1][e][b];
                h22i = -H22[1][e][b];
            } else {
                h11i = H11[1][e][b];
                h12i = H12[1][e][b];
                h21i = H21[1][e][b];
                h22i = H22[1][e][b];
            }
            }
            //Interpolation
            h11r_step = (H11[0][e+1][b] - h11r) * width;
            h12r_step = (H12[0][e+1][b] - h12r) * width;
            h21r_step = (H21[0][e+1][b] - h21r) * width;
            h22r_step = (H22[0][e+1][b] - h22r) * width;
            if (!PS_BASELINE && ps->enable_ipdopd) {
                h11i_step = (H11[1][e+1][b] - h11i) * width;
                h12i_step = (H12[1][e+1][b] - h12i) * width;
                h21i_step = (H21[1][e+1][b] - h21i) * width;
                h22i_step = (H22[1][e+1][b] - h22i) * width;
            }
            for (n = start + 1; n <= stop; n++) {
                //l is s, r is d
                float l_re = l[k][n][0];
                float l_im = l[k][n][1];
                float r_re = r[k][n][0];
                float r_im = r[k][n][1];
                h11r += h11r_step;
                h12r += h12r_step;
                h21r += h21r_step;
                h22r += h22r_step;
                if (!PS_BASELINE && ps->enable_ipdopd) {
                h11i += h11i_step;
                h12i += h12i_step;
                h21i += h21i_step;
                h22i += h22i_step;

                l[k][n][0] = h11r*l_re + h21r*r_re - h11i*l_im - h21i*r_im;
                l[k][n][1] = h11r*l_im + h21r*r_im + h11i*l_re + h21i*r_re;
                r[k][n][0] = h12r*l_re + h22r*r_re - h12i*l_im - h22i*r_im;
                r[k][n][1] = h12r*l_im + h22r*r_im + h12i*l_re + h22i*r_re;
                } else {
                l[k][n][0] = h11r*l_re + h21r*r_re;
                l[k][n][1] = h11r*l_im + h21r*r_im;
                r[k][n][0] = h12r*l_re + h22r*r_re;
                r[k][n][1] = h12r*l_im + h22r*r_im;
                }
            }
        }
    }
}

int ff_ps_apply(AVCodecContext *avctx, PSContext *ps, float L[2][38][64], float R[2][38][64], int top)
{
    float Lbuf[91][32][2];
    float Rbuf[91][32][2];
    const int len = 32;
    int is34 = ps->is34bands;

    top += NR_BANDS[is34] - 64;
    memset(ps->delay+top, 0, (NR_BANDS[is34] - top)*sizeof(ps->delay[0]));
    if (top < NR_ALLPASS_BANDS[is34])
        memset(ps->ap_delay + top, 0, (NR_ALLPASS_BANDS[is34] - top)*sizeof(ps->ap_delay[0]));

    hybrid_analysis(Lbuf, ps->in_buf, L, is34, len);
    decorrelation(ps, Rbuf, Lbuf, is34);
    stereo_processing(ps, Lbuf, Rbuf, is34);
    hybrid_synthesis(L, Lbuf, is34, len);
    hybrid_synthesis(R, Rbuf, is34, len);

    return 0;
}

#define PS_INIT_VLC_STATIC(num, size) \
    INIT_VLC_STATIC(&vlc_ps[num], 9, ps_tmp[num].table_size / ps_tmp[num].elem_size,    \
                    ps_tmp[num].ps_bits, 1, 1,                                          \
                    ps_tmp[num].ps_codes, ps_tmp[num].elem_size, ps_tmp[num].elem_size, \
                    size);

#define PS_VLC_ROW(name) \
    { name ## _codes, name ## _bits, sizeof(name ## _codes), sizeof(name ## _codes[0]) }

av_cold void ff_ps_init(void) {
    // Syntax initialization
    static const struct {
        const void *ps_codes, *ps_bits;
        const unsigned int table_size, elem_size;
    } ps_tmp[] = {
        PS_VLC_ROW(huff_iid_df1),
        PS_VLC_ROW(huff_iid_dt1),
        PS_VLC_ROW(huff_iid_df0),
        PS_VLC_ROW(huff_iid_dt0),
        PS_VLC_ROW(huff_icc_df),
        PS_VLC_ROW(huff_icc_dt),
        PS_VLC_ROW(huff_ipd_df),
        PS_VLC_ROW(huff_ipd_dt),
        PS_VLC_ROW(huff_opd_df),
        PS_VLC_ROW(huff_opd_dt),
    };

    PS_INIT_VLC_STATIC(0, 1544);
    PS_INIT_VLC_STATIC(1,  832);
    PS_INIT_VLC_STATIC(2, 1024);
    PS_INIT_VLC_STATIC(3, 1036);
    PS_INIT_VLC_STATIC(4,  544);
    PS_INIT_VLC_STATIC(5,  544);
    PS_INIT_VLC_STATIC(6,  512);
    PS_INIT_VLC_STATIC(7,  512);
    PS_INIT_VLC_STATIC(8,  512);
    PS_INIT_VLC_STATIC(9,  512);

    ps_tableinit();
}

av_cold void ff_ps_ctx_init(PSContext *ps)
{
    ipdopd_reset(ps->ipd_hist, ps->opd_hist);
}