/*

 * SIPR / ACELP.NET decoder

 *

 * Copyright (c) 2008 Vladimir Voroshilov

 * Copyright (c) 2009 Vitor Sessak

 *

 * 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 <math.h>

#include <stdint.h>

#include <string.h>

#include "libavutil/channel_layout.h"

#include "libavutil/float_dsp.h"

#include "libavutil/mathematics.h"

#define BITSTREAM_READER_LE

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "get_bits.h"

#include "lsp.h"

#include "acelp_vectors.h"

#include "acelp_pitch_delay.h"

#include "acelp_filters.h"

#include "celp_filters.h"

#define MAX_SUBFRAME_COUNT   5

#include "sipr.h"

#include "siprdata.h"

typedef struct SiprModeParam {

    const char *mode_name;

    uint16_t bits_per_frame;

    uint8_t subframe_count;

    uint8_t frames_per_packet;

    float pitch_sharp_factor;

    /* bitstream parameters */

    uint8_t number_of_fc_indexes;

    uint8_t ma_predictor_bits;  ///< size in bits of the switched MA predictor

    /** size in bits of the i-th stage vector of quantizer */

    uint8_t vq_indexes_bits[5];

    /** size in bits of the adaptive-codebook index for every subframe */

    uint8_t pitch_delay_bits[5];

    uint8_t gp_index_bits;

    uint8_t fc_index_bits[10]; ///< size in bits of the fixed codebook indexes

    uint8_t gc_index_bits;     ///< size in bits of the gain  codebook indexes

} SiprModeParam;

static const SiprModeParam modes[MODE_COUNT] = {

    [MODE_16k] = {

        .mode_name          = "16k",

        .bits_per_frame     = 160,

        .subframe_count     = SUBFRAME_COUNT_16k,

        .frames_per_packet  = 1,

        .pitch_sharp_factor = 0.00,

        .number_of_fc_indexes = 10,

        .ma_predictor_bits    = 1,

        .vq_indexes_bits      = {7, 8, 7, 7, 7},

        .pitch_delay_bits     = {9, 6},

        .gp_index_bits        = 4,

        .fc_index_bits        = {4, 5, 4, 5, 4, 5, 4, 5, 4, 5},

        .gc_index_bits        = 5

    },

    [MODE_8k5] = {

        .mode_name          = "8k5",

        .bits_per_frame     = 152,

        .subframe_count     = 3,

        .frames_per_packet  = 1,

        .pitch_sharp_factor = 0.8,

        .number_of_fc_indexes = 3,

        .ma_predictor_bits    = 0,

        .vq_indexes_bits      = {6, 7, 7, 7, 5},

        .pitch_delay_bits     = {8, 5, 5},

        .gp_index_bits        = 0,

        .fc_index_bits        = {9, 9, 9},

        .gc_index_bits        = 7

    },

    [MODE_6k5] = {

        .mode_name          = "6k5",

        .bits_per_frame     = 232,

        .subframe_count     = 3,

        .frames_per_packet  = 2,

        .pitch_sharp_factor = 0.8,

        .number_of_fc_indexes = 3,

        .ma_predictor_bits    = 0,

        .vq_indexes_bits      = {6, 7, 7, 7, 5},

        .pitch_delay_bits     = {8, 5, 5},

        .gp_index_bits        = 0,

        .fc_index_bits        = {5, 5, 5},

        .gc_index_bits        = 7

    },

    [MODE_5k0] = {

        .mode_name          = "5k0",

        .bits_per_frame     = 296,

        .subframe_count     = 5,

        .frames_per_packet  = 2,

        .pitch_sharp_factor = 0.85,

        .number_of_fc_indexes = 1,

        .ma_predictor_bits    = 0,

        .vq_indexes_bits      = {6, 7, 7, 7, 5},

        .pitch_delay_bits     = {8, 5, 8, 5, 5},

        .gp_index_bits        = 0,

        .fc_index_bits        = {10},

        .gc_index_bits        = 7

    }

};

const float ff_pow_0_5[] = {

    1.0/(1 <<  1), 1.0/(1 <<  2), 1.0/(1 <<  3), 1.0/(1 <<  4),

    1.0/(1 <<  5), 1.0/(1 <<  6), 1.0/(1 <<  7), 1.0/(1 <<  8),

    1.0/(1 <<  9), 1.0/(1 << 10), 1.0/(1 << 11), 1.0/(1 << 12),

    1.0/(1 << 13), 1.0/(1 << 14), 1.0/(1 << 15), 1.0/(1 << 16)

};

static void dequant(float *out, const int *idx, const float * const cbs[])

{

    int i;

    int stride  = 2;

    int num_vec = 5;

    for (i = 0; i < num_vec; i++)

        memcpy(out + stride*i, cbs[i] + stride*idx[i], stride*sizeof(float));

}

static void lsf_decode_fp(float *lsfnew, float *lsf_history,

                          const SiprParameters *parm)

{

    int i;

    float lsf_tmp[LP_FILTER_ORDER];

    dequant(lsf_tmp, parm->vq_indexes, lsf_codebooks);

    for (i = 0; i < LP_FILTER_ORDER; i++)

        lsfnew[i] = lsf_history[i] * 0.33 + lsf_tmp[i] + mean_lsf[i];

    ff_sort_nearly_sorted_floats(lsfnew, LP_FILTER_ORDER - 1);

    /* Note that a minimum distance is not enforced between the last value and

       the previous one, contrary to what is done in ff_acelp_reorder_lsf() */

    ff_set_min_dist_lsf(lsfnew, LSFQ_DIFF_MIN, LP_FILTER_ORDER - 1);

    lsfnew[9] = FFMIN(lsfnew[LP_FILTER_ORDER - 1], 1.3 * M_PI);

    memcpy(lsf_history, lsf_tmp, LP_FILTER_ORDER * sizeof(*lsf_history));

    for (i = 0; i < LP_FILTER_ORDER - 1; i++)

        lsfnew[i] = cos(lsfnew[i]);

    lsfnew[LP_FILTER_ORDER - 1] *= 6.153848 / M_PI;

}

/** Apply pitch lag to the fixed vector (AMR section 6.1.2). */

static void pitch_sharpening(int pitch_lag_int, float beta,

                             float *fixed_vector)

{

    int i;

    for (i = pitch_lag_int; i < SUBFR_SIZE; i++)

        fixed_vector[i] += beta * fixed_vector[i - pitch_lag_int];

}

/**

 * Extract decoding parameters from the input bitstream.

 * @param parms          parameters structure

 * @param pgb            pointer to initialized GetBitContext structure

 */

static void decode_parameters(SiprParameters* parms, GetBitContext *pgb,

                              const SiprModeParam *p)

{

    int i, j;

    if (p->ma_predictor_bits)

        parms->ma_pred_switch       = get_bits(pgb, p->ma_predictor_bits);

    for (i = 0; i < 5; i++)

        parms->vq_indexes[i]        = get_bits(pgb, p->vq_indexes_bits[i]);

    for (i = 0; i < p->subframe_count; i++) {

        parms->pitch_delay[i]       = get_bits(pgb, p->pitch_delay_bits[i]);

        if (p->gp_index_bits)

            parms->gp_index[i]      = get_bits(pgb, p->gp_index_bits);

        for (j = 0; j < p->number_of_fc_indexes; j++)

            parms->fc_indexes[i][j] = get_bits(pgb, p->fc_index_bits[j]);

        parms->gc_index[i]          = get_bits(pgb, p->gc_index_bits);

    }

}

static void sipr_decode_lp(float *lsfnew, const float *lsfold, float *Az,

                           int num_subfr)

{

    double lsfint[LP_FILTER_ORDER];

    int i,j;

    float t, t0 = 1.0 / num_subfr;

    t = t0 * 0.5;

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

        for (j = 0; j < LP_FILTER_ORDER; j++)

            lsfint[j] = lsfold[j] * (1 - t) + t * lsfnew[j];

        ff_amrwb_lsp2lpc(lsfint, Az, LP_FILTER_ORDER);

        Az += LP_FILTER_ORDER;

        t += t0;

    }

}

/**

 * Evaluate the adaptive impulse response.

 */

static void eval_ir(const float *Az, int pitch_lag, float *freq,

                    float pitch_sharp_factor)

{

    float tmp1[SUBFR_SIZE+1], tmp2[LP_FILTER_ORDER+1];

    int i;

    tmp1[0] = 1.0;

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

        tmp1[i+1] = Az[i] * ff_pow_0_55[i];

        tmp2[i  ] = Az[i] * ff_pow_0_7 [i];

    }

    memset(tmp1 + 11, 0, 37 * sizeof(float));

    ff_celp_lp_synthesis_filterf(freq, tmp2, tmp1, SUBFR_SIZE,

                                 LP_FILTER_ORDER);

    pitch_sharpening(pitch_lag, pitch_sharp_factor, freq);

}

/**

 * Evaluate the convolution of a vector with a sparse vector.

 */

static void convolute_with_sparse(float *out, const AMRFixed *pulses,

                                  const float *shape, int length)

{

    int i, j;

    memset(out, 0, length*sizeof(float));

    for (i = 0; i < pulses->n; i++)

        for (j = pulses->x[i]; j < length; j++)

            out[j] += pulses->y[i] * shape[j - pulses->x[i]];

}

/**

 * Apply postfilter, very similar to AMR one.

 */

static void postfilter_5k0(SiprContext *ctx, const float *lpc, float *samples)

{

    float buf[SUBFR_SIZE + LP_FILTER_ORDER];

    float *pole_out = buf + LP_FILTER_ORDER;

    float lpc_n[LP_FILTER_ORDER];

    float lpc_d[LP_FILTER_ORDER];

    int i;

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

        lpc_d[i] = lpc[i] * ff_pow_0_75[i];

        lpc_n[i] = lpc[i] * ff_pow_0_5 [i];

    };

    memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem,

           LP_FILTER_ORDER*sizeof(float));

    ff_celp_lp_synthesis_filterf(pole_out, lpc_d, samples, SUBFR_SIZE,

                                 LP_FILTER_ORDER);

    memcpy(ctx->postfilter_mem, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,

           LP_FILTER_ORDER*sizeof(float));

    ff_tilt_compensation(&ctx->tilt_mem, 0.4, pole_out, SUBFR_SIZE);

    memcpy(pole_out - LP_FILTER_ORDER, ctx->postfilter_mem5k0,

           LP_FILTER_ORDER*sizeof(*pole_out));

    memcpy(ctx->postfilter_mem5k0, pole_out + SUBFR_SIZE - LP_FILTER_ORDER,

           LP_FILTER_ORDER*sizeof(*pole_out));

    ff_celp_lp_zero_synthesis_filterf(samples, lpc_n, pole_out, SUBFR_SIZE,

                                      LP_FILTER_ORDER);

}

static void decode_fixed_sparse(AMRFixed *fixed_sparse, const int16_t *pulses,

                                SiprMode mode, int low_gain)

{

    int i;

    switch (mode) {

    case MODE_6k5:

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

            fixed_sparse->x[i] = 3 * (pulses[i] & 0xf) + i;

            fixed_sparse->y[i] = pulses[i] & 0x10 ? -1 : 1;

        }

        fixed_sparse->n = 3;

        break;

    case MODE_8k5:

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

            fixed_sparse->x[2*i    ] = 3 * ((pulses[i] >> 4) & 0xf) + i;

            fixed_sparse->x[2*i + 1] = 3 * ( pulses[i]       & 0xf) + i;

            fixed_sparse->y[2*i    ] = (pulses[i] & 0x100) ? -1.0: 1.0;

            fixed_sparse->y[2*i + 1] =

                (fixed_sparse->x[2*i + 1] < fixed_sparse->x[2*i]) ?

                -fixed_sparse->y[2*i    ] : fixed_sparse->y[2*i];

        }

        fixed_sparse->n = 6;

        break;

    case MODE_5k0:

    default:

        if (low_gain) {

            int offset = (pulses[0] & 0x200) ? 2 : 0;

            int val = pulses[0];

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

                int index = (val & 0x7) * 6 + 4 - i*2;

                fixed_sparse->y[i] = (offset + index) & 0x3 ? -1 : 1;

                fixed_sparse->x[i] = index;

                val >>= 3;

            }

            fixed_sparse->n = 3;

        } else {

            int pulse_subset = (pulses[0] >> 8) & 1;

            fixed_sparse->x[0] = ((pulses[0] >> 4) & 15) * 3 + pulse_subset;

            fixed_sparse->x[1] = ( pulses[0]       & 15) * 3 + pulse_subset + 1;

            fixed_sparse->y[0] = pulses[0] & 0x200 ? -1 : 1;

            fixed_sparse->y[1] = -fixed_sparse->y[0];

            fixed_sparse->n = 2;

        }

        break;

    }

}

static void decode_frame(SiprContext *ctx, SiprParameters *params,

                         float *out_data)

{

    int i, j;

    int subframe_count = modes[ctx->mode].subframe_count;

    int frame_size = subframe_count * SUBFR_SIZE;

    float Az[LP_FILTER_ORDER * MAX_SUBFRAME_COUNT];

    float *excitation;

    float ir_buf[SUBFR_SIZE + LP_FILTER_ORDER];

    float lsf_new[LP_FILTER_ORDER];

    float *impulse_response = ir_buf + LP_FILTER_ORDER;

    float *synth = ctx->synth_buf + 16; // 16 instead of LP_FILTER_ORDER for

                                        // memory alignment

    int t0_first = 0;

    AMRFixed fixed_cb;

    memset(ir_buf, 0, LP_FILTER_ORDER * sizeof(float));

    lsf_decode_fp(lsf_new, ctx->lsf_history, params);

    sipr_decode_lp(lsf_new, ctx->lsp_history, Az, subframe_count);

    memcpy(ctx->lsp_history, lsf_new, LP_FILTER_ORDER * sizeof(float));

    excitation = ctx->excitation + PITCH_DELAY_MAX + L_INTERPOL;

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

        float *pAz = Az + i*LP_FILTER_ORDER;

        float fixed_vector[SUBFR_SIZE];

        int T0,T0_frac;

        float pitch_gain, gain_code, avg_energy;

        ff_decode_pitch_lag(&T0, &T0_frac, params->pitch_delay[i], t0_first, i,

                            ctx->mode == MODE_5k0, 6);

        if (i == 0 || (i == 2 && ctx->mode == MODE_5k0))

            t0_first = T0;

        ff_acelp_interpolatef(excitation, excitation - T0 + (T0_frac <= 0),

                              ff_b60_sinc, 6,

                              2 * ((2 + T0_frac)%3 + 1), LP_FILTER_ORDER,

                              SUBFR_SIZE);

        decode_fixed_sparse(&fixed_cb, params->fc_indexes[i], ctx->mode,

                            ctx->past_pitch_gain < 0.8);

        eval_ir(pAz, T0, impulse_response, modes[ctx->mode].pitch_sharp_factor);

        convolute_with_sparse(fixed_vector, &fixed_cb, impulse_response,

                              SUBFR_SIZE);

        avg_energy = (0.01 + ff_scalarproduct_float_c(fixed_vector,

                                                      fixed_vector,

                                                      SUBFR_SIZE)) /

                     SUBFR_SIZE;

        ctx->past_pitch_gain = pitch_gain = gain_cb[params->gc_index[i]][0];

        gain_code = ff_amr_set_fixed_gain(gain_cb[params->gc_index[i]][1],

                                          avg_energy, ctx->energy_history,

                                          34 - 15.0/(0.05*M_LN10/M_LN2),

                                          pred);

        ff_weighted_vector_sumf(excitation, excitation, fixed_vector,

                                pitch_gain, gain_code, SUBFR_SIZE);

        pitch_gain *= 0.5 * pitch_gain;

        pitch_gain = FFMIN(pitch_gain, 0.4);

        ctx->gain_mem = 0.7 * ctx->gain_mem + 0.3 * pitch_gain;

        ctx->gain_mem = FFMIN(ctx->gain_mem, pitch_gain);

        gain_code *= ctx->gain_mem;

        for (j = 0; j < SUBFR_SIZE; j++)

            fixed_vector[j] = excitation[j] - gain_code * fixed_vector[j];

        if (ctx->mode == MODE_5k0) {

            postfilter_5k0(ctx, pAz, fixed_vector);

            ff_celp_lp_synthesis_filterf(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i*SUBFR_SIZE,

                                         pAz, excitation, SUBFR_SIZE,

                                         LP_FILTER_ORDER);

        }

        ff_celp_lp_synthesis_filterf(synth + i*SUBFR_SIZE, pAz, fixed_vector,

                                     SUBFR_SIZE, LP_FILTER_ORDER);

        excitation += SUBFR_SIZE;

    }

    memcpy(synth - LP_FILTER_ORDER, synth + frame_size - LP_FILTER_ORDER,

           LP_FILTER_ORDER * sizeof(float));

    if (ctx->mode == MODE_5k0) {

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

            float energy = ff_scalarproduct_float_c(ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,

                                                    ctx->postfilter_syn5k0 + LP_FILTER_ORDER + i * SUBFR_SIZE,

                                                    SUBFR_SIZE);

            ff_adaptive_gain_control(&synth[i * SUBFR_SIZE],

                                     &synth[i * SUBFR_SIZE], energy,

                                     SUBFR_SIZE, 0.9, &ctx->postfilter_agc);

        }

        memcpy(ctx->postfilter_syn5k0, ctx->postfilter_syn5k0 + frame_size,

               LP_FILTER_ORDER*sizeof(float));

    }

    memmove(ctx->excitation, excitation - PITCH_DELAY_MAX - L_INTERPOL,

           (PITCH_DELAY_MAX + L_INTERPOL) * sizeof(float));

    ff_acelp_apply_order_2_transfer_function(out_data, synth,

                                             (const float[2]) {-1.99997   , 1.000000000},

                                             (const float[2]) {-1.93307352, 0.935891986},

                                             0.939805806,

                                             ctx->highpass_filt_mem,

                                             frame_size);

}

static av_cold int sipr_decoder_init(AVCodecContext * avctx)

{

    SiprContext *ctx = avctx->priv_data;

    int i;

    switch (avctx->block_align) {

    case 20: ctx->mode = MODE_16k; break;

    case 19: ctx->mode = MODE_8k5; break;

    case 29: ctx->mode = MODE_6k5; break;

    case 37: ctx->mode = MODE_5k0; break;

    default:

        if      (avctx->bit_rate > 12200) ctx->mode = MODE_16k;

        else if (avctx->bit_rate > 7500 ) ctx->mode = MODE_8k5;

        else if (avctx->bit_rate > 5750 ) ctx->mode = MODE_6k5;

        else                              ctx->mode = MODE_5k0;

        av_log(avctx, AV_LOG_WARNING,

               "Invalid block_align: %d. Mode %s guessed based on bitrate: %"PRId64"\n",

               avctx->block_align, modes[ctx->mode].mode_name, avctx->bit_rate);

    }

    av_log(avctx, AV_LOG_DEBUG, "Mode: %s\n", modes[ctx->mode].mode_name);

    if (ctx->mode == MODE_16k) {

        ff_sipr_init_16k(ctx);

        ctx->decode_frame = ff_sipr_decode_frame_16k;

    } else {

        ctx->decode_frame = decode_frame;

    }

    for (i = 0; i < LP_FILTER_ORDER; i++)

        ctx->lsp_history[i] = cos((i+1) * M_PI / (LP_FILTER_ORDER + 1));

    for (i = 0; i < 4; i++)

        ctx->energy_history[i] = -14;

    av_channel_layout_uninit(&avctx->ch_layout);

    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;

    avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;

    return 0;

}

static int sipr_decode_frame(AVCodecContext *avctx, AVFrame *frame,

                             int *got_frame_ptr, AVPacket *avpkt)

{

    SiprContext *ctx = avctx->priv_data;

    const uint8_t *buf=avpkt->data;

    SiprParameters parm;

    const SiprModeParam *mode_par = &modes[ctx->mode];

    GetBitContext gb;

    float *samples;

    int subframe_size = ctx->mode == MODE_16k ? L_SUBFR_16k : SUBFR_SIZE;

    int i, ret;

    if (avpkt->size < (mode_par->bits_per_frame >> 3)) {

        av_log(avctx, AV_LOG_ERROR,

               "Error processing packet: packet size (%d) too small\n",

               avpkt->size);

        return AVERROR_INVALIDDATA;

    }

    /* get output buffer */

    frame->nb_samples = mode_par->frames_per_packet * subframe_size *

                        mode_par->subframe_count;

    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

        return ret;

    samples = (float *)frame->data[0];

    init_get_bits(&gb, buf, mode_par->bits_per_frame);

    for (i = 0; i < mode_par->frames_per_packet; i++) {

        decode_parameters(&parm, &gb, mode_par);

        ctx->decode_frame(ctx, &parm, samples);

        samples += subframe_size * mode_par->subframe_count;

    }

    *got_frame_ptr = 1;

    return mode_par->bits_per_frame >> 3;

}

const FFCodec ff_sipr_decoder = {

    .p.name         = "sipr",

    CODEC_LONG_NAME("RealAudio SIPR / ACELP.NET"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_SIPR,

    .priv_data_size = sizeof(SiprContext),

    .init           = sipr_decoder_init,

    FF_CODEC_DECODE_CB(sipr_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,

};