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/*

 * Simple free lossless/lossy audio codec

 * Copyright (c) 2004 Alex Beregszaszi

 *

 * 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 "avcodec.h"

#include "get_bits.h"

#include "golomb.h"

#include "internal.h"

/**

 * @file

 * Simple free lossless/lossy audio codec

 * Based on Paul Francis Harrison's Bonk (http://www.logarithmic.net/pfh/bonk)

 * Written and designed by Alex Beregszaszi

 *

 * TODO:

 *  - CABAC put/get_symbol

 *  - independent quantizer for channels

 *  - >2 channels support

 *  - more decorrelation types

 *  - more tap_quant tests

 *  - selectable intlist writers/readers (bonk-style, golomb, cabac)

 */

#define MAX_CHANNELS 2

#define MID_SIDE 0

#define LEFT_SIDE 1

#define RIGHT_SIDE 2

typedef struct SonicContext {

    int lossless, decorrelation;

    int num_taps, downsampling;

    double quantization;

    int channels, samplerate, block_align, frame_size;

    int *tap_quant;

    int *int_samples;

    int *coded_samples[MAX_CHANNELS];

    // for encoding

    int *tail;

    int tail_size;

    int *window;

    int window_size;

    // for decoding

    int *predictor_k;

    int *predictor_state[MAX_CHANNELS];

} SonicContext;

#define LATTICE_SHIFT   10

#define SAMPLE_SHIFT    4

#define LATTICE_FACTOR  (1 << LATTICE_SHIFT)

#define SAMPLE_FACTOR   (1 << SAMPLE_SHIFT)

#define BASE_QUANT      0.6

#define RATE_VARIATION  3.0

static inline int shift(int a,int b)

{

    return (a+(1<<(b-1))) >> b;

}

static inline int shift_down(int a,int b)

{

    return (a>>b)+(a<0);

}

#if 1

static inline int intlist_write(PutBitContext *pb, int *buf, int entries, int base_2_part)

{

    int i;

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

        set_se_golomb(pb, buf[i]);

    return 1;

}

static inline int intlist_read(GetBitContext *gb, int *buf, int entries, int base_2_part)

{

    int i;

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

        buf[i] = get_se_golomb(gb);

    return 1;

}

#else

#define ADAPT_LEVEL 8

static int bits_to_store(uint64_t x)

{

    int res = 0;

    while(x)

    {

        res++;

        x >>= 1;

    }

    return res;

}

static void write_uint_max(PutBitContext *pb, unsigned int value, unsigned int max)

{

    int i, bits;

    if (!max)

        return;

    bits = bits_to_store(max);

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

        put_bits(pb, 1, value & (1 << i));

    if ( (value | (1 << (bits-1))) <= max)

        put_bits(pb, 1, value & (1 << (bits-1)));

}

static unsigned int read_uint_max(GetBitContext *gb, int max)

{

    int i, bits, value = 0;

    if (!max)

        return 0;

    bits = bits_to_store(max);

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

        if (get_bits1(gb))

            value += 1 << i;

    if ( (value | (1<<(bits-1))) <= max)

        if (get_bits1(gb))

            value += 1 << (bits-1);

    return value;

}

static int intlist_write(PutBitContext *pb, int *buf, int entries, int base_2_part)

{

    int i, j, x = 0, low_bits = 0, max = 0;

    int step = 256, pos = 0, dominant = 0, any = 0;

    int *copy, *bits;

    copy = av_calloc(entries, sizeof(*copy));

    if (!copy)

        return AVERROR(ENOMEM);

    if (base_2_part)

    {

        int energy = 0;

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

            energy += abs(buf[i]);

        low_bits = bits_to_store(energy / (entries * 2));

        if (low_bits > 15)

            low_bits = 15;

        put_bits(pb, 4, low_bits);

    }

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

    {

        put_bits(pb, low_bits, abs(buf[i]));

        copy[i] = abs(buf[i]) >> low_bits;

        if (copy[i] > max)

            max = abs(copy[i]);

    }

    bits = av_calloc(entries*max, sizeof(*bits));

    if (!bits)

    {

//        av_free(copy);

        return AVERROR(ENOMEM);

    }

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

    {

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

            if (copy[j] >= i)

                bits[x++] = copy[j] > i;

    }

    // store bitstream

    while (pos < x)

    {

        int steplet = step >> 8;

        if (pos + steplet > x)

            steplet = x - pos;

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

            if (bits[i+pos] != dominant)

                any = 1;

        put_bits(pb, 1, any);

        if (!any)

        {

            pos += steplet;

            step += step / ADAPT_LEVEL;

        }

        else

        {

            int interloper = 0;

            while (((pos + interloper) < x) && (bits[pos + interloper] == dominant))

                interloper++;

            // note change

            write_uint_max(pb, interloper, (step >> 8) - 1);

            pos += interloper + 1;

            step -= step / ADAPT_LEVEL;

        }

        if (step < 256)

        {

            step = 65536 / step;

            dominant = !dominant;

        }

    }

    // store signs

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

        if (buf[i])

            put_bits(pb, 1, buf[i] < 0);

//    av_free(bits);

//    av_free(copy);

    return 0;

}

static int intlist_read(GetBitContext *gb, int *buf, int entries, int base_2_part)

{

    int i, low_bits = 0, x = 0;

    int n_zeros = 0, step = 256, dominant = 0;

    int pos = 0, level = 0;

    int *bits = av_calloc(entries, sizeof(*bits));

    if (!bits)

        return AVERROR(ENOMEM);

    if (base_2_part)

    {

        low_bits = get_bits(gb, 4);

        if (low_bits)

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

                buf[i] = get_bits(gb, low_bits);

    }

//    av_log(NULL, AV_LOG_INFO, "entries: %d, low bits: %d\n", entries, low_bits);

    while (n_zeros < entries)

    {

        int steplet = step >> 8;

        if (!get_bits1(gb))

        {

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

                bits[x++] = dominant;

            if (!dominant)

                n_zeros += steplet;

            step += step / ADAPT_LEVEL;

        }

        else

        {

            int actual_run = read_uint_max(gb, steplet-1);

//            av_log(NULL, AV_LOG_INFO, "actual run: %d\n", actual_run);

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

                bits[x++] = dominant;

            bits[x++] = !dominant;

            if (!dominant)

                n_zeros += actual_run;

            else

                n_zeros++;

            step -= step / ADAPT_LEVEL;

        }

        if (step < 256)

        {

            step = 65536 / step;

            dominant = !dominant;

        }

    }

    // reconstruct unsigned values

    n_zeros = 0;

    for (i = 0; n_zeros < entries; i++)

    {

        while(1)

        {

            if (pos >= entries)

            {

                pos = 0;

                level += 1 << low_bits;

            }

            if (buf[pos] >= level)

                break;

            pos++;

        }

        if (bits[i])

            buf[pos] += 1 << low_bits;

        else

            n_zeros++;

        pos++;

    }

//    av_free(bits);

    // read signs

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

        if (buf[i] && get_bits1(gb))

            buf[i] = -buf[i];

//    av_log(NULL, AV_LOG_INFO, "zeros: %d pos: %d\n", n_zeros, pos);

    return 0;

}

#endif

static void predictor_init_state(int *k, int *state, int order)

{

    int i;

    for (i = order-2; i >= 0; i--)

    {

        int j, p, x = state[i];

        for (j = 0, p = i+1; p < order; j++,p++)

            {

            int tmp = x + shift_down(k[j] * state[p], LATTICE_SHIFT);

            state[p] += shift_down(k[j]*x, LATTICE_SHIFT);

            x = tmp;

        }

    }

}

static int predictor_calc_error(int *k, int *state, int order, int error)

{

    int i, x = error - shift_down(k[order-1] * state[order-1], LATTICE_SHIFT);

#if 1

    int *k_ptr = &(k[order-2]),

        *state_ptr = &(state[order-2]);

    for (i = order-2; i >= 0; i--, k_ptr--, state_ptr--)

    {

        int k_value = *k_ptr, state_value = *state_ptr;

        x -= shift_down(k_value * state_value, LATTICE_SHIFT);

        state_ptr[1] = state_value + shift_down(k_value * x, LATTICE_SHIFT);

    }

#else

    for (i = order-2; i >= 0; i--)

    {

        x -= shift_down(k[i] * state[i], LATTICE_SHIFT);

        state[i+1] = state[i] + shift_down(k[i] * x, LATTICE_SHIFT);

    }

#endif

    // don't drift too far, to avoid overflows

    if (x >  (SAMPLE_FACTOR<<16)) x =  (SAMPLE_FACTOR<<16);

    if (x < -(SAMPLE_FACTOR<<16)) x = -(SAMPLE_FACTOR<<16);

    state[0] = x;

    return x;

}

#if CONFIG_SONIC_ENCODER || CONFIG_SONIC_LS_ENCODER

// Heavily modified Levinson-Durbin algorithm which

// copes better with quantization, and calculates the

// actual whitened result as it goes.

static void modified_levinson_durbin(int *window, int window_entries,

        int *out, int out_entries, int channels, int *tap_quant)

{

    int i;

    int *state = av_calloc(window_entries, sizeof(*state));

    memcpy(state, window, 4* window_entries);

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

    {

        int step = (i+1)*channels, k, j;

        double xx = 0.0, xy = 0.0;

#if 1

        int *x_ptr = &(window[step]);

        int *state_ptr = &(state[0]);

        j = window_entries - step;

        for (;j>0;j--,x_ptr++,state_ptr++)

        {

            double x_value = *x_ptr;

            double state_value = *state_ptr;

            xx += state_value*state_value;

            xy += x_value*state_value;

        }

#else

        for (j = 0; j <= (window_entries - step); j++);

        {

            double stepval = window[step+j];

            double stateval = window[j];

//            xx += (double)window[j]*(double)window[j];

//            xy += (double)window[step+j]*(double)window[j];

            xx += stateval*stateval;

            xy += stepval*stateval;

        }

#endif

        if (xx == 0.0)

            k = 0;

        else

            k = (int)(floor(-xy/xx * (double)LATTICE_FACTOR / (double)(tap_quant[i]) + 0.5));

        if (k > (LATTICE_FACTOR/tap_quant[i]))

            k = LATTICE_FACTOR/tap_quant[i];

        if (-k > (LATTICE_FACTOR/tap_quant[i]))

            k = -(LATTICE_FACTOR/tap_quant[i]);

        out[i] = k;

        k *= tap_quant[i];

#if 1

        x_ptr = &(window[step]);

        state_ptr = &(state[0]);

        j = window_entries - step;

        for (;j>0;j--,x_ptr++,state_ptr++)

        {

            int x_value = *x_ptr;

            int state_value = *state_ptr;

            *x_ptr = x_value + shift_down(k*state_value,LATTICE_SHIFT);

            *state_ptr = state_value + shift_down(k*x_value, LATTICE_SHIFT);

        }

#else

        for (j=0; j <= (window_entries - step); j++)

        {

            int stepval = window[step+j];

            int stateval=state[j];

            window[step+j] += shift_down(k * stateval, LATTICE_SHIFT);

            state[j] += shift_down(k * stepval, LATTICE_SHIFT);

        }

#endif

    }

    av_free(state);

}

static inline int code_samplerate(int samplerate)

{

    switch (samplerate)

    {

        case 44100: return 0;

        case 22050: return 1;

        case 11025: return 2;

        case 96000: return 3;

        case 48000: return 4;

        case 32000: return 5;

        case 24000: return 6;

        case 16000: return 7;

        case 8000: return 8;

    }

    return AVERROR(EINVAL);

}

static av_cold int sonic_encode_init(AVCodecContext *avctx)

{

    SonicContext *s = avctx->priv_data;

    PutBitContext pb;

    int i, version = 0;

    if (avctx->channels > MAX_CHANNELS)

    {

        av_log(avctx, AV_LOG_ERROR, "Only mono and stereo streams are supported by now\n");

        return AVERROR(EINVAL); /* only stereo or mono for now */

    }

    if (avctx->channels == 2)

        s->decorrelation = MID_SIDE;

    else

        s->decorrelation = 3;

    if (avctx->codec->id == AV_CODEC_ID_SONIC_LS)

    {

        s->lossless = 1;

        s->num_taps = 32;

        s->downsampling = 1;

        s->quantization = 0.0;

    }

    else

    {

        s->num_taps = 128;

        s->downsampling = 2;

        s->quantization = 1.0;

    }

    // max tap 2048

    if (s->num_taps < 32 || s->num_taps > 1024 || s->num_taps % 32) {

        av_log(avctx, AV_LOG_ERROR, "Invalid number of taps\n");

        return AVERROR_INVALIDDATA;

    }

    // generate taps

    s->tap_quant = av_calloc(s->num_taps, sizeof(*s->tap_quant));

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

        s->tap_quant[i] = ff_sqrt(i+1);

    s->channels = avctx->channels;

    s->samplerate = avctx->sample_rate;

    s->block_align = 2048LL*s->samplerate/(44100*s->downsampling);

    s->frame_size = s->channels*s->block_align*s->downsampling;

    s->tail_size = s->num_taps*s->channels;

    s->tail = av_calloc(s->tail_size, sizeof(*s->tail));

    if (!s->tail)

        return AVERROR(ENOMEM);

    s->predictor_k = av_calloc(s->num_taps, sizeof(*s->predictor_k) );

    if (!s->predictor_k)

        return AVERROR(ENOMEM);

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

    {

        s->coded_samples[i] = av_calloc(s->block_align, sizeof(**s->coded_samples));

        if (!s->coded_samples[i])

            return AVERROR(ENOMEM);

    }

    s->int_samples = av_calloc(s->frame_size, sizeof(*s->int_samples));

    s->window_size = ((2*s->tail_size)+s->frame_size);

    s->window = av_calloc(s->window_size, sizeof(*s->window));

    if (!s->window)

        return AVERROR(ENOMEM);

    avctx->extradata = av_mallocz(16);

    if (!avctx->extradata)

        return AVERROR(ENOMEM);

    init_put_bits(&pb, avctx->extradata, 16*8);

    put_bits(&pb, 2, version); // version

    if (version == 1)

    {

        put_bits(&pb, 2, s->channels);

        put_bits(&pb, 4, code_samplerate(s->samplerate));

    }

    put_bits(&pb, 1, s->lossless);

    if (!s->lossless)

        put_bits(&pb, 3, SAMPLE_SHIFT); // XXX FIXME: sample precision

    put_bits(&pb, 2, s->decorrelation);

    put_bits(&pb, 2, s->downsampling);

    put_bits(&pb, 5, (s->num_taps >> 5)-1); // 32..1024

    put_bits(&pb, 1, 0); // XXX FIXME: no custom tap quant table

    flush_put_bits(&pb);

    avctx->extradata_size = put_bits_count(&pb)/8;

    av_log(avctx, AV_LOG_INFO, "Sonic: ver: %d ls: %d dr: %d taps: %d block: %d frame: %d downsamp: %d\n",

        version, s->lossless, s->decorrelation, s->num_taps, s->block_align, s->frame_size, s->downsampling);

    avctx->frame_size = s->block_align*s->downsampling;

    return 0;

}

static av_cold int sonic_encode_close(AVCodecContext *avctx)

{

    SonicContext *s = avctx->priv_data;

    int i;

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

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

    av_freep(&s->predictor_k);

    av_freep(&s->tail);

    av_freep(&s->tap_quant);

    av_freep(&s->window);

    av_freep(&s->int_samples);

    return 0;

}

static int sonic_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,

                              const AVFrame *frame, int *got_packet_ptr)

{

    SonicContext *s = avctx->priv_data;

    PutBitContext pb;

    int i, j, ch, quant = 0, x = 0;

    int ret;

    const short *samples = (const int16_t*)frame->data[0];

    if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size * 5 + 1000)) < 0)

        return ret;

    init_put_bits(&pb, avpkt->data, avpkt->size);

    // short -> internal

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

        s->int_samples[i] = samples[i];

    if (!s->lossless)

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

            s->int_samples[i] = s->int_samples[i] << SAMPLE_SHIFT;

    switch(s->decorrelation)

    {

        case MID_SIDE:

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

            {

                s->int_samples[i] += s->int_samples[i+1];

                s->int_samples[i+1] -= shift(s->int_samples[i], 1);

            }

            break;

        case LEFT_SIDE:

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

                s->int_samples[i+1] -= s->int_samples[i];

            break;

        case RIGHT_SIDE:

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

                s->int_samples[i] -= s->int_samples[i+1];

            break;

    }

    memset(s->window, 0, 4* s->window_size);

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

        s->window[x++] = s->tail[i];

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

        s->window[x++] = s->int_samples[i];

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

        s->window[x++] = 0;

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

        s->tail[i] = s->int_samples[s->frame_size - s->tail_size + i];

    // generate taps

    modified_levinson_durbin(s->window, s->window_size,

                s->predictor_k, s->num_taps, s->channels, s->tap_quant);

    if ((ret = intlist_write(&pb, s->predictor_k, s->num_taps, 0)) < 0)

        return ret;

    for (ch = 0; ch < s->channels; ch++)

    {

        x = s->tail_size+ch;

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

        {

            int sum = 0;

            for (j = 0; j < s->downsampling; j++, x += s->channels)

                sum += s->window[x];

            s->coded_samples[ch][i] = sum;

        }

    }

    // simple rate control code

    if (!s->lossless)

    {

        double energy1 = 0.0, energy2 = 0.0;

        for (ch = 0; ch < s->channels; ch++)

        {

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

            {

                double sample = s->coded_samples[ch][i];

                energy2 += sample*sample;

                energy1 += fabs(sample);

            }

        }

        energy2 = sqrt(energy2/(s->channels*s->block_align));

        energy1 = sqrt(2.0)*energy1/(s->channels*s->block_align);

        // increase bitrate when samples are like a gaussian distribution

        // reduce bitrate when samples are like a two-tailed exponential distribution

        if (energy2 > energy1)

            energy2 += (energy2-energy1)*RATE_VARIATION;

        quant = (int)(BASE_QUANT*s->quantization*energy2/SAMPLE_FACTOR);

//        av_log(avctx, AV_LOG_DEBUG, "quant: %d energy: %f / %f\n", quant, energy1, energy2);

        quant = av_clip(quant, 1, 65534);

        set_ue_golomb(&pb, quant);

        quant *= SAMPLE_FACTOR;

    }

    // write out coded samples

    for (ch = 0; ch < s->channels; ch++)

    {

        if (!s->lossless)

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

                s->coded_samples[ch][i] = ROUNDED_DIV(s->coded_samples[ch][i], quant);

        if ((ret = intlist_write(&pb, s->coded_samples[ch], s->block_align, 1)) < 0)

            return ret;

    }

//    av_log(avctx, AV_LOG_DEBUG, "used bytes: %d\n", (put_bits_count(&pb)+7)/8);

    flush_put_bits(&pb);

    avpkt->size = (put_bits_count(&pb)+7)/8;

    *got_packet_ptr = 1;

    return 0;

}

#endif /* CONFIG_SONIC_ENCODER || CONFIG_SONIC_LS_ENCODER */

#if CONFIG_SONIC_DECODER

static const int samplerate_table[] =

    { 44100, 22050, 11025, 96000, 48000, 32000, 24000, 16000, 8000 };

static av_cold int sonic_decode_init(AVCodecContext *avctx)

{

    SonicContext *s = avctx->priv_data;

    GetBitContext gb;

    int i, version;

    s->channels = avctx->channels;

    s->samplerate = avctx->sample_rate;

    if (!avctx->extradata)

    {

        av_log(avctx, AV_LOG_ERROR, "No mandatory headers present\n");

        return AVERROR_INVALIDDATA;

    }

    init_get_bits8(&gb, avctx->extradata, avctx->extradata_size);

    version = get_bits(&gb, 2);

    if (version > 1)

    {

        av_log(avctx, AV_LOG_ERROR, "Unsupported Sonic version, please report\n");

        return AVERROR_INVALIDDATA;

    }

    if (version == 1)

    {

        s->channels = get_bits(&gb, 2);

        s->samplerate = samplerate_table[get_bits(&gb, 4)];

        av_log(avctx, AV_LOG_INFO, "Sonicv2 chans: %d samprate: %d\n",

            s->channels, s->samplerate);

    }

    if (s->channels > MAX_CHANNELS)

    {

        av_log(avctx, AV_LOG_ERROR, "Only mono and stereo streams are supported by now\n");

        return AVERROR_INVALIDDATA;

    }

    s->lossless = get_bits1(&gb);

    if (!s->lossless)

        skip_bits(&gb, 3); // XXX FIXME

    s->decorrelation = get_bits(&gb, 2);

    if (s->decorrelation != 3 && s->channels != 2) {

        av_log(avctx, AV_LOG_ERROR, "invalid decorrelation %d\n", s->decorrelation);

        return AVERROR_INVALIDDATA;

    }

    s->downsampling = get_bits(&gb, 2);

    if (!s->downsampling) {

        av_log(avctx, AV_LOG_ERROR, "invalid downsampling value\n");

        return AVERROR_INVALIDDATA;

    }

    s->num_taps = (get_bits(&gb, 5)+1)<<5;

    if (get_bits1(&gb)) // XXX FIXME

        av_log(avctx, AV_LOG_INFO, "Custom quant table\n");

    s->block_align = 2048LL*s->samplerate/(44100*s->downsampling);

    s->frame_size = s->channels*s->block_align*s->downsampling;

//    avctx->frame_size = s->block_align;

    av_log(avctx, AV_LOG_INFO, "Sonic: ver: %d ls: %d dr: %d taps: %d block: %d frame: %d downsamp: %d\n",

        version, s->lossless, s->decorrelation, s->num_taps, s->block_align, s->frame_size, s->downsampling);

    // generate taps

    s->tap_quant = av_calloc(s->num_taps, sizeof(*s->tap_quant));

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

        s->tap_quant[i] = ff_sqrt(i+1);

    s->predictor_k = av_calloc(s->num_taps, sizeof(*s->predictor_k));

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

    {

        s->predictor_state[i] = av_calloc(s->num_taps, sizeof(**s->predictor_state));

        if (!s->predictor_state[i])

            return AVERROR(ENOMEM);

    }

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

    {

        s->coded_samples[i] = av_calloc(s->block_align, sizeof(**s->coded_samples));

        if (!s->coded_samples[i])

            return AVERROR(ENOMEM);

    }

    s->int_samples = av_calloc(s->frame_size, sizeof(*s->int_samples));

    avctx->sample_fmt = AV_SAMPLE_FMT_S16;

    return 0;

}

static av_cold int sonic_decode_close(AVCodecContext *avctx)

{

    SonicContext *s = avctx->priv_data;

    int i;

    av_freep(&s->int_samples);

    av_freep(&s->tap_quant);

    av_freep(&s->predictor_k);

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

    {

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

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

    }

    return 0;

}

static int sonic_decode_frame(AVCodecContext *avctx,

                            void *data, int *got_frame_ptr,

                            AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    SonicContext *s = avctx->priv_data;

    GetBitContext gb;

    int i, quant, ch, j, ret;

    int16_t *samples;

    AVFrame *frame = data;

    if (buf_size == 0) return 0;

    frame->nb_samples = s->frame_size / avctx->channels;

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

        return ret;

    samples = (int16_t *)frame->data[0];

//    av_log(NULL, AV_LOG_INFO, "buf_size: %d\n", buf_size);

    init_get_bits8(&gb, buf, buf_size);

    intlist_read(&gb, s->predictor_k, s->num_taps, 0);

    // dequantize

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

        s->predictor_k[i] *= s->tap_quant[i];

    if (s->lossless)

        quant = 1;

    else

        quant = get_ue_golomb(&gb) * SAMPLE_FACTOR;

//    av_log(NULL, AV_LOG_INFO, "quant: %d\n", quant);

    for (ch = 0; ch < s->channels; ch++)

    {

        int x = ch;

        predictor_init_state(s->predictor_k, s->predictor_state[ch], s->num_taps);

        intlist_read(&gb, s->coded_samples[ch], s->block_align, 1);

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

        {

            for (j = 0; j < s->downsampling - 1; j++)

            {

                s->int_samples[x] = predictor_calc_error(s->predictor_k, s->predictor_state[ch], s->num_taps, 0);

                x += s->channels;

            }

            s->int_samples[x] = predictor_calc_error(s->predictor_k, s->predictor_state[ch], s->num_taps, s->coded_samples[ch][i] * quant);

            x += s->channels;

        }

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

            s->predictor_state[ch][i] = s->int_samples[s->frame_size - s->channels + ch - i*s->channels];

    }

    switch(s->decorrelation)

    {

        case MID_SIDE:

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

            {

                s->int_samples[i+1] += shift(s->int_samples[i], 1);

                s->int_samples[i] -= s->int_samples[i+1];

            }

            break;

        case LEFT_SIDE:

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

                s->int_samples[i+1] += s->int_samples[i];

            break;

        case RIGHT_SIDE:

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

                s->int_samples[i] += s->int_samples[i+1];

            break;

    }

    if (!s->lossless)

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

            s->int_samples[i] = shift(s->int_samples[i], SAMPLE_SHIFT);

    // internal -> short

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

        samples[i] = av_clip_int16(s->int_samples[i]);

    align_get_bits(&gb);

    *got_frame_ptr = 1;

    return (get_bits_count(&gb)+7)/8;

}

AVCodec ff_sonic_decoder = {

    .name           = "sonic",

    .long_name      = NULL_IF_CONFIG_SMALL("Sonic"),

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_SONIC,

    .priv_data_size = sizeof(SonicContext),

    .init           = sonic_decode_init,

    .close          = sonic_decode_close,

    .decode         = sonic_decode_frame,

    .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_EXPERIMENTAL,

};

#endif /* CONFIG_SONIC_DECODER */

#if CONFIG_SONIC_ENCODER

AVCodec ff_sonic_encoder = {

    .name           = "sonic",

    .long_name      = NULL_IF_CONFIG_SMALL("Sonic"),

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_SONIC,

    .priv_data_size = sizeof(SonicContext),

    .init           = sonic_encode_init,

    .encode2        = sonic_encode_frame,

    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE },

    .capabilities   = CODEC_CAP_EXPERIMENTAL,

    .close          = sonic_encode_close,

};

#endif

#if CONFIG_SONIC_LS_ENCODER

AVCodec ff_sonic_ls_encoder = {

    .name           = "sonicls",

    .long_name      = NULL_IF_CONFIG_SMALL("Sonic lossless"),

    .type           = AVMEDIA_TYPE_AUDIO,

    .id             = AV_CODEC_ID_SONIC_LS,

    .priv_data_size = sizeof(SonicContext),

    .init           = sonic_encode_init,

    .encode2        = sonic_encode_frame,

    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_NONE },

    .capabilities   = CODEC_CAP_EXPERIMENTAL,

    .close          = sonic_encode_close,

};

#endif