PeerStreamer

/*

 * COOK compatible decoder

 * Copyright (c) 2003 Sascha Sommer

 * Copyright (c) 2005 Benjamin Larsson

 *

 * 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

 *

 */

/**

 * @file cook.c

 * Cook compatible decoder.

 * This decoder handles RealNetworks, RealAudio G2 data.

 * Cook is identified by the codec name cook in RM files.

 *

 * To use this decoder, a calling application must supply the extradata

 * bytes provided from the RM container; 8+ bytes for mono streams and

 * 16+ for stereo streams (maybe more).

 *

 * Codec technicalities (all this assume a buffer length of 1024):

 * Cook works with several different techniques to achieve its compression.

 * In the timedomain the buffer is divided into 8 pieces and quantized. If

 * two neighboring pieces have different quantization index a smooth

 * quantization curve is used to get a smooth overlap between the different

 * pieces.

 * To get to the transformdomain Cook uses a modulated lapped transform.

 * The transform domain has 50 subbands with 20 elements each. This

 * means only a maximum of 50*20=1000 coefficients are used out of the 1024

 * available.

 */

#include <math.h>

#include <stddef.h>

#include <stdio.h>

#include "avcodec.h"

#include "bitstream.h"

#include "dsputil.h"

#include "common.h"

#include "bytestream.h"

#include "cookdata.h"

/* the different Cook versions */

#define MONO            0x1000001

#define STEREO          0x1000002

#define JOINT_STEREO    0x1000003

#define MC_COOK         0x2000000   //multichannel Cook, not supported

#define SUBBAND_SIZE    20

//#define COOKDEBUG

typedef struct {

    int     size;

    int     loccode[8];

    int     levcode[8];

} COOKgain;

typedef struct {

    GetBitContext       gb;

    /* stream data */

    int                 nb_channels;

    int                 joint_stereo;

    int                 bit_rate;

    int                 sample_rate;

    int                 samples_per_channel;

    int                 samples_per_frame;

    int                 subbands;

    int                 log2_numvector_size;

    int                 numvector_size;                //1 << log2_numvector_size;

    int                 js_subband_start;

    int                 total_subbands;

    int                 num_vectors;

    int                 bits_per_subpacket;

    int                 cookversion;

    /* states */

    int                 random_state;

    /* transform data */

    FFTContext          fft_ctx;

    DECLARE_ALIGNED_16(FFTSample, mlt_tmp[1024]);  /* temporary storage for imlt */

    float*              mlt_window;

    float*              mlt_precos;

    float*              mlt_presin;

    float*              mlt_postcos;

    int                 fft_size;

    int                 fft_order;

    int                 mlt_size;       //modulated lapped transform size

    /* gain buffers */

    COOKgain            *gain_ptr1[2];

    COOKgain            *gain_ptr2[2];

    COOKgain            gain_1;

    COOKgain            gain_2;

    COOKgain            gain_3;

    COOKgain            gain_4;

    /* VLC data */

    int                 js_vlc_bits;

    VLC                 envelope_quant_index[13];

    VLC                 sqvh[7];          //scalar quantization

    VLC                 ccpl;             //channel coupling

    /* generatable tables and related variables */

    int                 gain_size_factor;

    float               gain_table[23];

    float               pow2tab[127];

    float               rootpow2tab[127];

    /* data buffers */

    uint8_t*            decoded_bytes_buffer;

    DECLARE_ALIGNED_16(float,mono_mdct_output[2048]);

    float               mono_previous_buffer1[1024];

    float               mono_previous_buffer2[1024];

    float               decode_buffer_1[1024];

    float               decode_buffer_2[1024];

} COOKContext;

/* debug functions */

#ifdef COOKDEBUG

static void dump_float_table(float* table, int size, int delimiter) {

    int i=0;

    av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i);

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

        av_log(NULL, AV_LOG_ERROR, "%5.1f, ", table[i]);

        if ((i+1)%delimiter == 0) av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i+1);

    }

}

static void dump_int_table(int* table, int size, int delimiter) {

    int i=0;

    av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i);

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

        av_log(NULL, AV_LOG_ERROR, "%d, ", table[i]);

        if ((i+1)%delimiter == 0) av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i+1);

    }

}

static void dump_short_table(short* table, int size, int delimiter) {

    int i=0;

    av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i);

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

        av_log(NULL, AV_LOG_ERROR, "%d, ", table[i]);

        if ((i+1)%delimiter == 0) av_log(NULL,AV_LOG_ERROR,"\n[%d]: ",i+1);

    }

}

#endif

/*************** init functions ***************/

/* table generator */

static void init_pow2table(COOKContext *q){

    int i;

    q->pow2tab[63] = 1.0;

    for (i=1 ; i<64 ; i++){

        q->pow2tab[63+i]=(float)((uint64_t)1<<i);

        q->pow2tab[63-i]=1.0/(float)((uint64_t)1<<i);

    }

}

/* table generator */

static void init_rootpow2table(COOKContext *q){

    int i;

    q->rootpow2tab[63] = 1.0;

    for (i=1 ; i<64 ; i++){

        q->rootpow2tab[63+i]=sqrt((float)((uint64_t)1<<i));

        q->rootpow2tab[63-i]=sqrt(1.0/(float)((uint64_t)1<<i));

    }

}

/* table generator */

static void init_gain_table(COOKContext *q) {

    int i;

    q->gain_size_factor = q->samples_per_channel/8;

    for (i=0 ; i<23 ; i++) {

        q->gain_table[i] = pow((double)q->pow2tab[i+52] ,

                               (1.0/(double)q->gain_size_factor));

    }

}

static int init_cook_vlc_tables(COOKContext *q) {

    int i, result;

    result = 0;

    for (i=0 ; i<13 ; i++) {

        result &= init_vlc (&q->envelope_quant_index[i], 9, 24,

            envelope_quant_index_huffbits[i], 1, 1,

            envelope_quant_index_huffcodes[i], 2, 2, 0);

    }

    av_log(NULL,AV_LOG_DEBUG,"sqvh VLC init\n");

    for (i=0 ; i<7 ; i++) {

        result &= init_vlc (&q->sqvh[i], vhvlcsize_tab[i], vhsize_tab[i],

            cvh_huffbits[i], 1, 1,

            cvh_huffcodes[i], 2, 2, 0);

    }

    if (q->nb_channels==2 && q->joint_stereo==1){

        result &= init_vlc (&q->ccpl, 6, (1<<q->js_vlc_bits)-1,

            ccpl_huffbits[q->js_vlc_bits-2], 1, 1,

            ccpl_huffcodes[q->js_vlc_bits-2], 2, 2, 0);

        av_log(NULL,AV_LOG_DEBUG,"Joint-stereo VLC used.\n");

    }

    av_log(NULL,AV_LOG_DEBUG,"VLC tables initialized.\n");

    return result;

}

static int init_cook_mlt(COOKContext *q) {

    int j;

    float alpha;

    /* Allocate the buffers, could be replaced with a static [512]

       array if needed. */

    q->mlt_size = q->samples_per_channel;

    q->mlt_window = av_malloc(sizeof(float)*q->mlt_size);

    q->mlt_precos = av_malloc(sizeof(float)*q->mlt_size/2);

    q->mlt_presin = av_malloc(sizeof(float)*q->mlt_size/2);

    q->mlt_postcos = av_malloc(sizeof(float)*q->mlt_size/2);

    /* Initialize the MLT window: simple sine window. */

    alpha = M_PI / (2.0 * (float)q->mlt_size);

    for(j=0 ; j<q->mlt_size ; j++) {

        q->mlt_window[j] = sin((j + 512.0/(float)q->mlt_size) * alpha);

    }

    /* pre/post twiddle factors */

    for (j=0 ; j<q->mlt_size/2 ; j++){

        q->mlt_precos[j] = cos( ((j+0.25)*M_PI)/q->mlt_size);

        q->mlt_presin[j] = sin( ((j+0.25)*M_PI)/q->mlt_size);

        q->mlt_postcos[j] = (float)sqrt(2.0/(float)q->mlt_size)*cos( ((float)j*M_PI) /q->mlt_size); //sqrt(2/MLT_size) = scalefactor

    }

    /* Initialize the FFT. */

    ff_fft_init(&q->fft_ctx, av_log2(q->mlt_size)-1, 0);

    av_log(NULL,AV_LOG_DEBUG,"FFT initialized, order = %d.\n",

           av_log2(q->samples_per_channel)-1);

    return (int)(q->mlt_window && q->mlt_precos && q->mlt_presin && q->mlt_postcos);

}

/*************** init functions end ***********/

/**

 * Cook indata decoding, every 32 bits are XORed with 0x37c511f2.

 * Why? No idea, some checksum/error detection method maybe.

 *

 * Out buffer size: extra bytes are needed to cope with

 * padding/missalignment.

 * Subpackets passed to the decoder can contain two, consecutive

 * half-subpackets, of identical but arbitrary size.

 *          1234 1234 1234 1234  extraA extraB

 * Case 1:  AAAA BBBB              0      0

 * Case 2:  AAAA ABBB BB--         3      3

 * Case 3:  AAAA AABB BBBB         2      2

 * Case 4:  AAAA AAAB BBBB BB--    1      5

 *

 * Nice way to waste CPU cycles.

 *

 * @param inbuffer  pointer to byte array of indata

 * @param out       pointer to byte array of outdata

 * @param bytes     number of bytes

 */

#define DECODE_BYTES_PAD1(bytes) (3 - ((bytes)+3) % 4)

#define DECODE_BYTES_PAD2(bytes) ((bytes) % 4 + DECODE_BYTES_PAD1(2 * (bytes)))

static inline int decode_bytes(uint8_t* inbuffer, uint8_t* out, int bytes){

    int i, off;

    uint32_t c;

    uint32_t* buf;

    uint32_t* obuf = (uint32_t*) out;

    /* FIXME: 64 bit platforms would be able to do 64 bits at a time.

     * I'm too lazy though, should be something like

     * for(i=0 ; i<bitamount/64 ; i++)

     *     (int64_t)out[i] = 0x37c511f237c511f2^be2me_64(int64_t)in[i]);

     * Buffer alignment needs to be checked. */

    off = (int)((long)inbuffer & 3);

    buf = (uint32_t*) (inbuffer - off);

    c = be2me_32((0x37c511f2 >> (off*8)) | (0x37c511f2 << (32-(off*8))));

    bytes += 3 + off;

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

        obuf[i] = c ^ buf[i];

    return off;

}

/**

 * Cook uninit

 */

static int cook_decode_close(AVCodecContext *avctx)

{

    int i;

    COOKContext *q = avctx->priv_data;

    av_log(avctx,AV_LOG_DEBUG, "Deallocating memory.\n");

    /* Free allocated memory buffers. */

    av_free(q->mlt_window);

    av_free(q->mlt_precos);

    av_free(q->mlt_presin);

    av_free(q->mlt_postcos);

    av_free(q->decoded_bytes_buffer);

    /* Free the transform. */

    ff_fft_end(&q->fft_ctx);

    /* Free the VLC tables. */

    for (i=0 ; i<13 ; i++) {

        free_vlc(&q->envelope_quant_index[i]);

    }

    for (i=0 ; i<7 ; i++) {

        free_vlc(&q->sqvh[i]);

    }

    if(q->nb_channels==2 && q->joint_stereo==1 ){

        free_vlc(&q->ccpl);

    }

    av_log(NULL,AV_LOG_DEBUG,"Memory deallocated.\n");

    return 0;

}

/**

 * Fill the COOKgain structure for the timedomain quantization.

 *

 * @param q                 pointer to the COOKContext

 * @param gaininfo          pointer to the COOKgain

 */

static void decode_gain_info(GetBitContext *gb, COOKgain* gaininfo) {

    int i;

    while (get_bits1(gb)) {}

    gaininfo->size = get_bits_count(gb) - 1;     //amount of elements*2 to update

    if (get_bits_count(gb) - 1 <= 0) return;

    for (i=0 ; i<gaininfo->size ; i++){

        gaininfo->loccode[i] = get_bits(gb,3);

        if (get_bits1(gb)) {

            gaininfo->levcode[i] = get_bits(gb,4) - 7;  //convert to signed

        } else {

            gaininfo->levcode[i] = -1;

        }

    }

}

/**

 * Create the quant index table needed for the envelope.

 *

 * @param q                 pointer to the COOKContext

 * @param quant_index_table pointer to the array

 */

static void decode_envelope(COOKContext *q, int* quant_index_table) {

    int i,j, vlc_index;

    int bitbias;

    bitbias = get_bits_count(&q->gb);

    quant_index_table[0]= get_bits(&q->gb,6) - 6;       //This is used later in categorize

    for (i=1 ; i < q->total_subbands ; i++){

        vlc_index=i;

        if (i >= q->js_subband_start * 2) {

            vlc_index-=q->js_subband_start;

        } else {

            vlc_index/=2;

            if(vlc_index < 1) vlc_index = 1;

        }

        if (vlc_index>13) vlc_index = 13;           //the VLC tables >13 are identical to No. 13

        j = get_vlc2(&q->gb, q->envelope_quant_index[vlc_index-1].table,

                     q->envelope_quant_index[vlc_index-1].bits,2);

        quant_index_table[i] = quant_index_table[i-1] + j - 12;    //differential encoding

    }

}

/**

 * Create the quant value table.

 *

 * @param q                 pointer to the COOKContext

 * @param quant_value_table pointer to the array

 */

static void inline dequant_envelope(COOKContext *q, int* quant_index_table,

                                    float* quant_value_table){

    int i;

    for(i=0 ; i < q->total_subbands ; i++){

        quant_value_table[i] = q->rootpow2tab[quant_index_table[i]+63];

    }

}

/**

 * Calculate the category and category_index vector.

 *

 * @param q                     pointer to the COOKContext

 * @param quant_index_table     pointer to the array

 * @param category              pointer to the category array

 * @param category_index        pointer to the category_index array

 */

static void categorize(COOKContext *q, int* quant_index_table,

                       int* category, int* category_index){

    int exp_idx, bias, tmpbias, bits_left, num_bits, index, v, i, j;

    int exp_index2[102];

    int exp_index1[102];

    int tmp_categorize_array1[128];

    int tmp_categorize_array1_idx=0;

    int tmp_categorize_array2[128];

    int tmp_categorize_array2_idx=0;

    int category_index_size=0;

    bits_left =  q->bits_per_subpacket - get_bits_count(&q->gb);

    if(bits_left > q->samples_per_channel) {

        bits_left = q->samples_per_channel +

                    ((bits_left - q->samples_per_channel)*5)/8;

        //av_log(NULL, AV_LOG_ERROR, "bits_left = %d\n",bits_left);

    }

    memset(&exp_index1,0,102*sizeof(int));

    memset(&exp_index2,0,102*sizeof(int));

    memset(&tmp_categorize_array1,0,128*sizeof(int));

    memset(&tmp_categorize_array2,0,128*sizeof(int));

    bias=-32;

    /* Estimate bias. */

    for (i=32 ; i>0 ; i=i/2){

        num_bits = 0;

        index = 0;

        for (j=q->total_subbands ; j>0 ; j--){

            exp_idx = (i - quant_index_table[index] + bias) / 2;

            if (exp_idx<0){

                exp_idx=0;

            } else if(exp_idx >7) {

                exp_idx=7;

            }

            index++;

            num_bits+=expbits_tab[exp_idx];

        }

        if(num_bits >= bits_left - 32){

            bias+=i;

        }

    }

    /* Calculate total number of bits. */

    num_bits=0;

    for (i=0 ; i<q->total_subbands ; i++) {

        exp_idx = (bias - quant_index_table[i]) / 2;

        if (exp_idx<0) {

            exp_idx=0;

        } else if(exp_idx >7) {

            exp_idx=7;

        }

        num_bits += expbits_tab[exp_idx];

        exp_index1[i] = exp_idx;

        exp_index2[i] = exp_idx;

    }

    tmpbias = bias = num_bits;

    for (j = 1 ; j < q->numvector_size ; j++) {

        if (tmpbias + bias > 2*bits_left) {  /* ---> */

            int max = -999999;

            index=-1;

            for (i=0 ; i<q->total_subbands ; i++){

                if (exp_index1[i] < 7) {

                    v = (-2*exp_index1[i]) - quant_index_table[i] - 32;

                    if ( v >= max) {

                        max = v;

                        index = i;

                    }

                }

            }

            if(index==-1)break;

            tmp_categorize_array1[tmp_categorize_array1_idx++] = index;

            tmpbias -= expbits_tab[exp_index1[index]] -

                       expbits_tab[exp_index1[index]+1];

            ++exp_index1[index];

        } else {  /* <--- */

            int min = 999999;

            index=-1;

            for (i=0 ; i<q->total_subbands ; i++){

                if(exp_index2[i] > 0){

                    v = (-2*exp_index2[i])-quant_index_table[i];

                    if ( v < min) {

                        min = v;

                        index = i;

                    }

                }

            }

            if(index == -1)break;

            tmp_categorize_array2[tmp_categorize_array2_idx++] = index;

            tmpbias -= expbits_tab[exp_index2[index]] -

                       expbits_tab[exp_index2[index]-1];

            --exp_index2[index];

        }

    }

    for(i=0 ; i<q->total_subbands ; i++)

        category[i] = exp_index2[i];

    /* Concatenate the two arrays. */

    for(i=tmp_categorize_array2_idx-1 ; i >= 0; i--)

        category_index[category_index_size++] =  tmp_categorize_array2[i];

    for(i=0;i<tmp_categorize_array1_idx;i++)

        category_index[category_index_size++ ] =  tmp_categorize_array1[i];

    /* FIXME: mc_sich_ra8_20.rm triggers this, not sure with what we

       should fill the remaining bytes. */

    for(i=category_index_size;i<q->numvector_size;i++)

        category_index[i]=0;

}

/**

 * Expand the category vector.

 *

 * @param q                     pointer to the COOKContext

 * @param category              pointer to the category array

 * @param category_index        pointer to the category_index array

 */

static void inline expand_category(COOKContext *q, int* category,

                                   int* category_index){

    int i;

    for(i=0 ; i<q->num_vectors ; i++){

        ++category[category_index[i]];

    }

}

/**

 * The real requantization of the mltcoefs

 *

 * @param q                     pointer to the COOKContext

 * @param index                 index

 * @param band                  current subband

 * @param quant_value_table     pointer to the array

 * @param subband_coef_index    array of indexes to quant_centroid_tab

 * @param subband_coef_noise    use random noise instead of predetermined value

 * @param mlt_buffer            pointer to the mlt buffer

 */

static void scalar_dequant(COOKContext *q, int index, int band,

                           float* quant_value_table, int* subband_coef_index,

                           int* subband_coef_noise, float* mlt_buffer){

    int i;

    float f1;

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

        if (subband_coef_index[i]) {

            if (subband_coef_noise[i]) {

                f1 = -quant_centroid_tab[index][subband_coef_index[i]];

            } else {

                f1 = quant_centroid_tab[index][subband_coef_index[i]];

            }

        } else {

            /* noise coding if subband_coef_noise[i] == 0 */

            q->random_state = q->random_state * 214013 + 2531011;    //typical RNG numbers

            f1 = randsign[(q->random_state/0x1000000)&1] * dither_tab[index]; //>>31

        }

        mlt_buffer[band*20+ i] = f1 * quant_value_table[band];

    }

}

/**

 * Unpack the subband_coef_index and subband_coef_noise vectors.

 *

 * @param q                     pointer to the COOKContext

 * @param category              pointer to the category array

 * @param subband_coef_index    array of indexes to quant_centroid_tab

 * @param subband_coef_noise    use random noise instead of predetermined value

 */

static int unpack_SQVH(COOKContext *q, int category, int* subband_coef_index,

                       int* subband_coef_noise) {

    int i,j;

    int vlc, vd ,tmp, result;

    int ub;

    int cb;

    vd = vd_tab[category];

    result = 0;

    for(i=0 ; i<vpr_tab[category] ; i++){

        ub = get_bits_count(&q->gb);

        vlc = get_vlc2(&q->gb, q->sqvh[category].table, q->sqvh[category].bits, 3);

        cb = get_bits_count(&q->gb);

        if (q->bits_per_subpacket < get_bits_count(&q->gb)){

            vlc = 0;

            result = 1;

        }

        for(j=vd-1 ; j>=0 ; j--){

            tmp = (vlc * invradix_tab[category])/0x100000;

            subband_coef_index[vd*i+j] = vlc - tmp * (kmax_tab[category]+1);

            vlc = tmp;

        }

        for(j=0 ; j<vd ; j++){

            if (subband_coef_index[i*vd + j]) {

                if(get_bits_count(&q->gb) < q->bits_per_subpacket){

                    subband_coef_noise[i*vd+j] = get_bits1(&q->gb);

                } else {

                    result=1;

                    subband_coef_noise[i*vd+j]=0;

                }

            } else {

                subband_coef_noise[i*vd+j]=0;

            }

        }

    }

    return result;

}

/**

 * Fill the mlt_buffer with mlt coefficients.

 *

 * @param q                 pointer to the COOKContext

 * @param category          pointer to the category array

 * @param quant_value_table pointer to the array

 * @param mlt_buffer        pointer to mlt coefficients

 */

static void decode_vectors(COOKContext* q, int* category,

                           float* quant_value_table, float* mlt_buffer){

    /* A zero in this table means that the subband coefficient is

       random noise coded. */

    int subband_coef_noise[SUBBAND_SIZE];

    /* A zero in this table means that the subband coefficient is a

       positive multiplicator. */

    int subband_coef_index[SUBBAND_SIZE];

    int band, j;

    int index=0;

    for(band=0 ; band<q->total_subbands ; band++){

        index = category[band];

        if(category[band] < 7){

            if(unpack_SQVH(q, category[band], subband_coef_index, subband_coef_noise)){

                index=7;

                for(j=0 ; j<q->total_subbands ; j++) category[band+j]=7;

            }

        }

        if(index==7) {

            memset(subband_coef_index, 0, sizeof(subband_coef_index));

            memset(subband_coef_noise, 0, sizeof(subband_coef_noise));

        }

        scalar_dequant(q, index, band, quant_value_table, subband_coef_index,

                       subband_coef_noise, mlt_buffer);

    }

    if(q->total_subbands*SUBBAND_SIZE >= q->samples_per_channel){

        return;

    }

}

/**

 * function for decoding mono data

 *

 * @param q                 pointer to the COOKContext

 * @param mlt_buffer1       pointer to left channel mlt coefficients

 * @param mlt_buffer2       pointer to right channel mlt coefficients

 */

static void mono_decode(COOKContext *q, float* mlt_buffer) {

    int category_index[128];

    float quant_value_table[102];

    int quant_index_table[102];

    int category[128];

    memset(&category, 0, 128*sizeof(int));

    memset(&quant_value_table, 0, 102*sizeof(int));

    memset(&category_index, 0, 128*sizeof(int));

    decode_envelope(q, quant_index_table);

    q->num_vectors = get_bits(&q->gb,q->log2_numvector_size);

    dequant_envelope(q, quant_index_table, quant_value_table);

    categorize(q, quant_index_table, category, category_index);

    expand_category(q, category, category_index);

    decode_vectors(q, category, quant_value_table, mlt_buffer);

}

/**

 * The modulated lapped transform, this takes transform coefficients

 * and transforms them into timedomain samples. This is done through

 * an FFT-based algorithm with pre- and postrotation steps.

 * A window and reorder step is also included.

 *

 * @param q                 pointer to the COOKContext

 * @param inbuffer          pointer to the mltcoefficients

 * @param outbuffer         pointer to the timedomain buffer

 * @param mlt_tmp           pointer to temporary storage space

 */

static void cook_imlt(COOKContext *q, float* inbuffer, float* outbuffer,

                      float* mlt_tmp){

    int i;

    /* prerotation */

    for(i=0 ; i<q->mlt_size ; i+=2){

        outbuffer[i] = (q->mlt_presin[i/2] * inbuffer[q->mlt_size-1-i]) +

                       (q->mlt_precos[i/2] * inbuffer[i]);

        outbuffer[i+1] = (q->mlt_precos[i/2] * inbuffer[q->mlt_size-1-i]) -

                         (q->mlt_presin[i/2] * inbuffer[i]);

    }

    /* FFT */

    ff_fft_permute(&q->fft_ctx, (FFTComplex *) outbuffer);

    ff_fft_calc (&q->fft_ctx, (FFTComplex *) outbuffer);

    /* postrotation */

    for(i=0 ; i<q->mlt_size ; i+=2){

        mlt_tmp[i] =               (q->mlt_postcos[(q->mlt_size-1-i)/2] * outbuffer[i+1]) +

                                   (q->mlt_postcos[i/2] * outbuffer[i]);

        mlt_tmp[q->mlt_size-1-i] = (q->mlt_postcos[(q->mlt_size-1-i)/2] * outbuffer[i]) -

                                   (q->mlt_postcos[i/2] * outbuffer[i+1]);

    }

    /* window and reorder */

    for(i=0 ; i<q->mlt_size/2 ; i++){

        outbuffer[i] = mlt_tmp[q->mlt_size/2-1-i] * q->mlt_window[i];

        outbuffer[q->mlt_size-1-i]= mlt_tmp[q->mlt_size/2-1-i] *

                                    q->mlt_window[q->mlt_size-1-i];

        outbuffer[q->mlt_size+i]= mlt_tmp[q->mlt_size/2+i] *

                                  q->mlt_window[q->mlt_size-1-i];

        outbuffer[2*q->mlt_size-1-i]= -(mlt_tmp[q->mlt_size/2+i] *

                                      q->mlt_window[i]);

    }

}

/**

 * the actual requantization of the timedomain samples

 *

 * @param q                 pointer to the COOKContext

 * @param buffer            pointer to the timedomain buffer

 * @param gain_index        index for the block multiplier

 * @param gain_index_next   index for the next block multiplier

 */

static void interpolate(COOKContext *q, float* buffer,

                        int gain_index, int gain_index_next){

    int i;

    float fc1, fc2;

    fc1 = q->pow2tab[gain_index+63];

    if(gain_index == gain_index_next){              //static gain

        for(i=0 ; i<q->gain_size_factor ; i++){

            buffer[i]*=fc1;

        }

        return;

    } else {                                        //smooth gain

        fc2 = q->gain_table[11 + (gain_index_next-gain_index)];

        for(i=0 ; i<q->gain_size_factor ; i++){

            buffer[i]*=fc1;

            fc1*=fc2;

        }

        return;

    }

}

/**

 * timedomain requantization of the timedomain samples

 *

 * @param q                 pointer to the COOKContext

 * @param buffer            pointer to the timedomain buffer

 * @param gain_now          current gain structure

 * @param gain_previous     previous gain structure

 */

static void gain_window(COOKContext *q, float* buffer, COOKgain* gain_now,

                        COOKgain* gain_previous){

    int i, index;

    int gain_index[9];

    int tmp_gain_index;

    gain_index[8]=0;

    index = gain_previous->size;

    for (i=7 ; i>=0 ; i--) {

        if(index && gain_previous->loccode[index-1]==i) {

            gain_index[i] = gain_previous->levcode[index-1];

            index--;

        } else {

            gain_index[i]=gain_index[i+1];

        }

    }

    /* This is applied to the to be previous data buffer. */

    for(i=0;i<8;i++){

        interpolate(q, &buffer[q->samples_per_channel+q->gain_size_factor*i],

                    gain_index[i], gain_index[i+1]);

    }

    tmp_gain_index = gain_index[0];

    index = gain_now->size;

    for (i=7 ; i>=0 ; i--) {

        if(index && gain_now->loccode[index-1]==i) {

            gain_index[i]= gain_now->levcode[index-1];

            index--;

        } else {

            gain_index[i]=gain_index[i+1];

        }

    }

    /* This is applied to the to be current block. */

    for(i=0;i<8;i++){

        interpolate(q, &buffer[i*q->gain_size_factor],

                    tmp_gain_index+gain_index[i],

                    tmp_gain_index+gain_index[i+1]);

    }

}

/**

 * mlt overlapping and buffer management

 *

 * @param q                 pointer to the COOKContext

 * @param buffer            pointer to the timedomain buffer

 * @param gain_now          current gain structure

 * @param gain_previous     previous gain structure

 * @param previous_buffer   pointer to the previous buffer to be used for overlapping

 *

 */

static void gain_compensate(COOKContext *q, float* buffer, COOKgain* gain_now,

                            COOKgain* gain_previous, float* previous_buffer) {

    int i;

    if((gain_now->size  || gain_previous->size)) {

        gain_window(q, buffer, gain_now, gain_previous);

    }

    /* Overlap with the previous block. */

    for(i=0 ; i<q->samples_per_channel ; i++) buffer[i]+=previous_buffer[i];

    /* Save away the current to be previous block. */

    memcpy(previous_buffer, buffer+q->samples_per_channel,

           sizeof(float)*q->samples_per_channel);

}

/**

 * function for getting the jointstereo coupling information

 *

 * @param q                 pointer to the COOKContext

 * @param decouple_tab      decoupling array

 *

 */

static void decouple_info(COOKContext *q, int* decouple_tab){

    int length, i;

    if(get_bits1(&q->gb)) {

        if(cplband[q->js_subband_start] > cplband[q->subbands-1]) return;

        length = cplband[q->subbands-1] - cplband[q->js_subband_start] + 1;

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

            decouple_tab[cplband[q->js_subband_start] + i] = get_vlc2(&q->gb, q->ccpl.table, q->ccpl.bits, 2);

        }

        return;

    }

    if(cplband[q->js_subband_start] > cplband[q->subbands-1]) return;

    length = cplband[q->subbands-1] - cplband[q->js_subband_start] + 1;

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

       decouple_tab[cplband[q->js_subband_start] + i] = get_bits(&q->gb, q->js_vlc_bits);

    }

    return;

}

/**

 * function for decoding joint stereo data

 *

 * @param q                 pointer to the COOKContext

 * @param mlt_buffer1       pointer to left channel mlt coefficients

 * @param mlt_buffer2       pointer to right channel mlt coefficients

 */

static void joint_decode(COOKContext *q, float* mlt_buffer1,

                         float* mlt_buffer2) {

    int i,j;

    int decouple_tab[SUBBAND_SIZE];

    float decode_buffer[1060];

    int idx, cpl_tmp,tmp_idx;

    float f1,f2;

    float* cplscale;

    memset(decouple_tab, 0, sizeof(decouple_tab));

    memset(decode_buffer, 0, sizeof(decode_buffer));

    /* Make sure the buffers are zeroed out. */

    memset(mlt_buffer1,0, 1024*sizeof(float));

    memset(mlt_buffer2,0, 1024*sizeof(float));

    decouple_info(q, decouple_tab);

    mono_decode(q, decode_buffer);

    /* The two channels are stored interleaved in decode_buffer. */

    for (i=0 ; i<q->js_subband_start ; i++) {

        for (j=0 ; j<SUBBAND_SIZE ; j++) {

            mlt_buffer1[i*20+j] = decode_buffer[i*40+j];

            mlt_buffer2[i*20+j] = decode_buffer[i*40+20+j];

        }

    }

    /* When we reach js_subband_start (the higher frequencies)

       the coefficients are stored in a coupling scheme. */

    idx = (1 << q->js_vlc_bits) - 1;

    for (i=q->js_subband_start ; i<q->subbands ; i++) {

        cpl_tmp = cplband[i];

        idx -=decouple_tab[cpl_tmp];

        cplscale = (float*)cplscales[q->js_vlc_bits-2];  //choose decoupler table

        f1 = cplscale[decouple_tab[cpl_tmp]];

        f2 = cplscale[idx-1];

        for (j=0 ; j<SUBBAND_SIZE ; j++) {

            tmp_idx = ((q->js_subband_start + i)*20)+j;

            mlt_buffer1[20*i + j] = f1 * decode_buffer[tmp_idx];

            mlt_buffer2[20*i + j] = f2 * decode_buffer[tmp_idx];

        }

        idx = (1 << q->js_vlc_bits) - 1;

    }

}

/**

 * First part of subpacket decoding:

 *  decode raw stream bytes and read gain info.

 *

 * @param q                 pointer to the COOKContext

 * @param inbuffer          pointer to raw stream data

 * @param gain_ptr          array of current/prev gain pointers

 */

static inline void

decode_bytes_and_gain(COOKContext *q, uint8_t *inbuffer,

                      COOKgain *gain_ptr[])

{

    int offset;

    offset = decode_bytes(inbuffer, q->decoded_bytes_buffer,

                          q->bits_per_subpacket/8);

    init_get_bits(&q->gb, q->decoded_bytes_buffer + offset,

                  q->bits_per_subpacket);

    decode_gain_info(&q->gb, gain_ptr[0]);

    /* Swap current and previous gains */

    FFSWAP(COOKgain *, gain_ptr[0], gain_ptr[1]);

}

/**

 * Final part of subpacket decoding:

 *  Apply modulated lapped transform, gain compensation,

 *  clip and convert to integer.

 *

 * @param q                 pointer to the COOKContext

 * @param decode_buffer     pointer to the mlt coefficients

 * @param gain_ptr          array of current/prev gain pointers

 * @param previous_buffer   pointer to the previous buffer to be used for overlapping

 * @param out               pointer to the output buffer

 * @param chan              0: left or single channel, 1: right channel

 */

static inline void

mlt_compensate_output(COOKContext *q, float *decode_buffer,

                      COOKgain *gain_ptr[], float *previous_buffer,

                      int16_t *out, int chan)

{

    int j;

    cook_imlt(q, decode_buffer, q->mono_mdct_output, q->mlt_tmp);

    gain_compensate(q, q->mono_mdct_output, gain_ptr[0],

                    gain_ptr[1], previous_buffer);

    /* Clip and convert floats to 16 bits.

     */

    for (j = 0; j < q->samples_per_channel; j++) {

        out[chan + q->nb_channels * j] =

          av_clip(lrintf(q->mono_mdct_output[j]), -32768, 32767);

    }

}

/**

 * Cook subpacket decoding. This function returns one decoded subpacket,

 * usually 1024 samples per channel.

 *

 * @param q                 pointer to the COOKContext

 * @param inbuffer          pointer to the inbuffer

 * @param sub_packet_size   subpacket size

 * @param outbuffer         pointer to the outbuffer

 */

static int decode_subpacket(COOKContext *q, uint8_t *inbuffer,

                            int sub_packet_size, int16_t *outbuffer) {

    /* packet dump */

//    for (i=0 ; i<sub_packet_size ; i++) {

//        av_log(NULL, AV_LOG_ERROR, "%02x", inbuffer[i]);

//    }

//    av_log(NULL, AV_LOG_ERROR, "\n");

    decode_bytes_and_gain(q, inbuffer, q->gain_ptr1);

    if (q->joint_stereo) {

        joint_decode(q, q->decode_buffer_1, q->decode_buffer_2);

    } else {

        mono_decode(q, q->decode_buffer_1);

        if (q->nb_channels == 2) {

            decode_bytes_and_gain(q, inbuffer + sub_packet_size/2,

                                  q->gain_ptr2);

            mono_decode(q, q->decode_buffer_2);

        }

    }

    mlt_compensate_output(q, q->decode_buffer_1, q->gain_ptr1,

                          q->mono_previous_buffer1, outbuffer, 0);

    if (q->nb_channels == 2) {

        if (q->joint_stereo) {

            mlt_compensate_output(q, q->decode_buffer_2, q->gain_ptr1,

                                  q->mono_previous_buffer2, outbuffer, 1);

        } else {

            mlt_compensate_output(q, q->decode_buffer_2, q->gain_ptr2,

                                  q->mono_previous_buffer2, outbuffer, 1);

        }

    }

    return q->samples_per_frame * sizeof(int16_t);

}

/**

 * Cook frame decoding

 *

 * @param avctx     pointer to the AVCodecContext

 */

static int cook_decode_frame(AVCodecContext *avctx,

            void *data, int *data_size,

            uint8_t *buf, int buf_size) {

    COOKContext *q = avctx->priv_data;

    if (buf_size < avctx->block_align)

        return buf_size;

    *data_size = decode_subpacket(q, buf, avctx->block_align, data);

    return avctx->block_align;

}

#ifdef COOKDEBUG

static void dump_cook_context(COOKContext *q)

{

    //int i=0;

#define PRINT(a,b) av_log(NULL,AV_LOG_ERROR," %s = %d\n", a, b);

    av_log(NULL,AV_LOG_ERROR,"COOKextradata\n");

    av_log(NULL,AV_LOG_ERROR,"cookversion=%x\n",q->cookversion);

    if (q->cookversion > STEREO) {

        PRINT("js_subband_start",q->js_subband_start);

        PRINT("js_vlc_bits",q->js_vlc_bits);

    }

    av_log(NULL,AV_LOG_ERROR,"COOKContext\n");

    PRINT("nb_channels",q->nb_channels);

    PRINT("bit_rate",q->bit_rate);

    PRINT("sample_rate",q->sample_rate);

    PRINT("samples_per_channel",q->samples_per_channel);

    PRINT("samples_per_frame",q->samples_per_frame);

    PRINT("subbands",q->subbands);

    PRINT("random_state",q->random_state);

    PRINT("mlt_size",q->mlt_size);

    PRINT("js_subband_start",q->js_subband_start);

    PRINT("log2_numvector_size",q->log2_numvector_size);

    PRINT("numvector_size",q->numvector_size);

    PRINT("total_subbands",q->total_subbands);

}

#endif

/**

 * Cook initialization

 *

 * @param avctx     pointer to the AVCodecContext

 */

static int cook_decode_init(AVCodecContext *avctx)

{

    COOKContext *q = avctx->priv_data;

    uint8_t *edata_ptr = avctx->extradata;

    /* Take care of the codec specific extradata. */

    if (avctx->extradata_size <= 0) {

        av_log(avctx,AV_LOG_ERROR,"Necessary extradata missing!\n");

        return -1;

    } else {

        /* 8 for mono, 16 for stereo, ? for multichannel

           Swap to right endianness so we don't need to care later on. */

        av_log(avctx,AV_LOG_DEBUG,"codecdata_length=%d\n",avctx->extradata_size);

        if (avctx->extradata_size >= 8){

            q->cookversion = bytestream_get_be32(&edata_ptr);

            q->samples_per_frame =  bytestream_get_be16(&edata_ptr);

            q->subbands = bytestream_get_be16(&edata_ptr);

        }

        if (avctx->extradata_size >= 16){

            bytestream_get_be32(&edata_ptr);    //Unknown unused

            q->js_subband_start = bytestream_get_be16(&edata_ptr);

            q->js_vlc_bits = bytestream_get_be16(&edata_ptr);

        }

    }

    /* Take data from the AVCodecContext (RM container). */

    q->sample_rate = avctx->sample_rate;

    q->nb_channels = avctx->channels;

    q->bit_rate = avctx->bit_rate;

    /* Initialize state. */

    q->random_state = 1;

    /* Initialize extradata related variables. */

    q->samples_per_channel = q->samples_per_frame / q->nb_channels;

    q->bits_per_subpacket = avctx->block_align * 8;

    /* Initialize default data states. */

    q->log2_numvector_size = 5;

    q->total_subbands = q->subbands;

    /* Initialize version-dependent variables */

    av_log(NULL,AV_LOG_DEBUG,"q->cookversion=%x\n",q->cookversion);

    q->joint_stereo = 0;

    switch (q->cookversion) {

        case MONO:

            if (q->nb_channels != 1) {

                av_log(avctx,AV_LOG_ERROR,"Container channels != 1, report sample!\n");

                return -1;

            }

            av_log(avctx,AV_LOG_DEBUG,"MONO\n");

            break;

        case STEREO:

            if (q->nb_channels != 1) {

                q->bits_per_subpacket = q->bits_per_subpacket/2;

            }

            av_log(avctx,AV_LOG_DEBUG,"STEREO\n");

            break;

        case JOINT_STEREO:

            if (q->nb_channels != 2) {

                av_log(avctx,AV_LOG_ERROR,"Container channels != 2, report sample!\n");

                return -1;

            }

            av_log(avctx,AV_LOG_DEBUG,"JOINT_STEREO\n");

            if (avctx->extradata_size >= 16){

                q->total_subbands = q->subbands + q->js_subband_start;

                q->joint_stereo = 1;

            }

            if (q->samples_per_channel > 256) {

                q->log2_numvector_size  = 6;

            }

            if (q->samples_per_channel > 512) {

                q->log2_numvector_size  = 7;

            }

            break;

        case MC_COOK:

            av_log(avctx,AV_LOG_ERROR,"MC_COOK not supported!\n");

            return -1;

            break;

        default:

            av_log(avctx,AV_LOG_ERROR,"Unknown Cook version, report sample!\n");

            return -1;

            break;

    }

    /* Initialize variable relations */

    q->mlt_size = q->samples_per_channel;

    q->numvector_size = (1 << q->log2_numvector_size);

    /* Generate tables */

    init_rootpow2table(q);

    init_pow2table(q);

    init_gain_table(q);

    if (init_cook_vlc_tables(q) != 0)

        return -1;

    if(avctx->block_align >= UINT_MAX/2)

        return -1;

    /* Pad the databuffer with:

       DECODE_BYTES_PAD1 or DECODE_BYTES_PAD2 for decode_bytes(),

       FF_INPUT_BUFFER_PADDING_SIZE, for the bitstreamreader. */

    if (q->nb_channels==2 && q->joint_stereo==0) {

        q->decoded_bytes_buffer =

          av_mallocz(avctx->block_align/2

                     + DECODE_BYTES_PAD2(avctx->block_align/2)

                     + FF_INPUT_BUFFER_PADDING_SIZE);

    } else {

        q->decoded_bytes_buffer =

          av_mallocz(avctx->block_align

                     + DECODE_BYTES_PAD1(avctx->block_align)

                     + FF_INPUT_BUFFER_PADDING_SIZE);

    }

    if (q->decoded_bytes_buffer == NULL)

        return -1;

    q->gain_ptr1[0] = &q->gain_1;

    q->gain_ptr1[1] = &q->gain_2;

    q->gain_ptr2[0] = &q->gain_3;

    q->gain_ptr2[1] = &q->gain_4;

    /* Initialize transform. */

    if ( init_cook_mlt(q) == 0 )

        return -1;

    /* Try to catch some obviously faulty streams, othervise it might be exploitable */

    if (q->total_subbands > 53) {

        av_log(avctx,AV_LOG_ERROR,"total_subbands > 53, report sample!\n");

        return -1;

    }

    if (q->subbands > 50) {

        av_log(avctx,AV_LOG_ERROR,"subbands > 50, report sample!\n");

        return -1;

    }

    if ((q->samples_per_channel == 256) || (q->samples_per_channel == 512) || (q->samples_per_channel == 1024)) {

    } else {

        av_log(avctx,AV_LOG_ERROR,"unknown amount of samples_per_channel = %d, report sample!\n",q->samples_per_channel);

        return -1;

    }

    if ((q->js_vlc_bits > 6) || (q->js_vlc_bits < 0)) {

        av_log(avctx,AV_LOG_ERROR,"q->js_vlc_bits = %d, only >= 0 and <= 6 allowed!\n",q->js_vlc_bits);

        return -1;

    }

#ifdef COOKDEBUG

    dump_cook_context(q);

#endif

    return 0;

}

AVCodec cook_decoder =

{

    .name = "cook",

    .type = CODEC_TYPE_AUDIO,

    .id = CODEC_ID_COOK,

    .priv_data_size = sizeof(COOKContext),

    .init = cook_decode_init,

    .close = cook_decode_close,

    .decode = cook_decode_frame,

};