cook.c.svn-base

mediastreamer2是开源的网络传输媒体流的库

/*
 * 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. Bastardization of the G.722.1 standard.
 * 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 "bytestream.h"
#include "random.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 *now;
    int *previous;
} cook_gains;

typedef struct cook {
    /*
     * The following 5 functions provide the lowlevel arithmetic on
     * the internal audio buffers.
     */
    void (* scalar_dequant)(struct cook *q, int index, int quant_index,
                            int* subband_coef_index, int* subband_coef_sign,
                            float* mlt_p);

    void (* decouple) (struct cook *q,
                       int subband,
                       float f1, float f2,
                       float *decode_buffer,
                       float *mlt_buffer1, float *mlt_buffer2);

    void (* imlt_window) (struct cook *q, float *buffer1,
                          cook_gains *gains_ptr, float *previous_buffer);

    void (* interpolate) (struct cook *q, float* buffer,
                          int gain_index, int gain_index_next);

    void (* saturate_output) (struct cook *q, int chan, int16_t *out);

    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 */
    AVRandomState       random_state;

    /* transform data */
    MDCTContext         mdct_ctx;
    DECLARE_ALIGNED_16(FFTSample, mdct_tmp[1024]);  /* temporary storage for imlt */
    float*              mlt_window;

    /* gain buffers */
    cook_gains          gains1;
    cook_gains          gains2;
    int                 gain_1[9];
    int                 gain_2[9];
    int                 gain_3[9];
    int                 gain_4[9];

    /* 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];
    float               decode_buffer_0[1060]; /* static allocation for joint decode */

    const float         *cplscales[5];
} 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;
    int mlt_size = q->samples_per_channel;

    if ((q->mlt_window = av_malloc(sizeof(float)*mlt_size)) == 0)
      return -1;

    /* Initialize the MLT window: simple sine window. */
    alpha = M_PI / (2.0 * (float)mlt_size);
    for(j=0 ; j<mlt_size ; j++)
        q->mlt_window[j] = sin((j + 0.5) * alpha) * sqrt(2.0 / q->samples_per_channel);

    /* Initialize the MDCT. */
    if (ff_mdct_init(&q->mdct_ctx, av_log2(mlt_size)+1, 1)) {
      av_free(q->mlt_window);
      return -1;
    }
    av_log(NULL,AV_LOG_DEBUG,"MDCT initialized, order = %d.\n",
           av_log2(mlt_size)+1);

    return 0;
}

static const float *maybe_reformat_buffer32 (COOKContext *q, const float *ptr, int n)
{
    if (1)
        return ptr;
}

static void init_cplscales_table (COOKContext *q) {
    int i;
    for (i=0;i<5;i++)
        q->cplscales[i] = maybe_reformat_buffer32 (q, cplscales[i], (1<<(i+2))-1);
}

/*************** 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/misalignment.
 * 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(const uint8_t* inbuffer, uint8_t* out, int bytes){
    int i, off;
    uint32_t c;
    const 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 = (const 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->decoded_bytes_buffer);

    /* Free the transform. */
    ff_mdct_end(&q->mdct_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 gain array for the timedomain quantization.
 *
 * @param q                 pointer to the COOKContext
 * @param gaininfo[9]       array of gain indices
 */

static void decode_gain_info(GetBitContext *gb, int *gaininfo)
{
    int i, n;

    while (get_bits1(gb)) {}
    n = get_bits_count(gb) - 1;     //amount of elements*2 to update

    i = 0;
    while (n--) {
        int index = get_bits(gb, 3);
        int gain = get_bits1(gb) ? get_bits(gb, 4) - 7 : -1;

        while (i <= index) gaininfo[i++] = gain;
    }
    while (i <= 8) gaininfo[i++] = 0;
}

/**
 * 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;

    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,