www.pudn.com > ffmpeg_src2007.rar > adpcm.c


/* 
 * ADPCM codecs 
 * Copyright (c) 2001-2003 The ffmpeg Project 
 * 
 * This library 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 of the License, or (at your option) any later version. 
 * 
 * This library 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 this library; if not, write to the Free Software 
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 
 */ 
#include "avcodec.h" 
#include "bitstream.h" 
 
/** 
 * @file adpcm.c 
 * ADPCM codecs. 
 * First version by Francois Revol (revol@free.fr) 
 * Fringe ADPCM codecs (e.g., DK3, DK4, Westwood) 
 *   by Mike Melanson (melanson@pcisys.net) 
 * CD-ROM XA ADPCM codec by BERO 
 * EA ADPCM decoder by Robin Kay (komadori@myrealbox.com) 
 * 
 * Features and limitations: 
 * 
 * Reference documents: 
 * http://www.pcisys.net/~melanson/codecs/simpleaudio.html 
 * http://www.geocities.com/SiliconValley/8682/aud3.txt 
 * http://openquicktime.sourceforge.net/plugins.htm 
 * XAnim sources (xa_codec.c) http://www.rasnaimaging.com/people/lapus/download.html 
 * http://www.cs.ucla.edu/~leec/mediabench/applications.html 
 * SoX source code http://home.sprynet.com/~cbagwell/sox.html 
 * 
 * CD-ROM XA: 
 * http://ku-www.ss.titech.ac.jp/~yatsushi/xaadpcm.html 
 * vagpack & depack http://homepages.compuserve.de/bITmASTER32/psx-index.html 
 * readstr http://www.geocities.co.jp/Playtown/2004/ 
 */ 
 
#define BLKSIZE 1024 
 
#define CLAMP_TO_SHORT(value) \ 
if (value > 32767) \ 
    value = 32767; \ 
else if (value < -32768) \ 
    value = -32768; \ 
 
/* step_table[] and index_table[] are from the ADPCM reference source */ 
/* This is the index table: */ 
static const int index_table[16] = { 
    -1, -1, -1, -1, 2, 4, 6, 8, 
    -1, -1, -1, -1, 2, 4, 6, 8, 
}; 
 
/** 
 * This is the step table. Note that many programs use slight deviations from 
 * this table, but such deviations are negligible: 
 */ 
static const int step_table[89] = { 
    7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 
    19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 
    50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 
    130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 
    337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 
    876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 
    2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 
    5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 
    15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 
}; 
 
/* These are for MS-ADPCM */ 
/* AdaptationTable[], AdaptCoeff1[], and AdaptCoeff2[] are from libsndfile */ 
static const int AdaptationTable[] = { 
        230, 230, 230, 230, 307, 409, 512, 614, 
        768, 614, 512, 409, 307, 230, 230, 230 
}; 
 
static const int AdaptCoeff1[] = { 
        256, 512, 0, 192, 240, 460, 392 
}; 
 
static const int AdaptCoeff2[] = { 
        0, -256, 0, 64, 0, -208, -232 
}; 
 
/* These are for CD-ROM XA ADPCM */ 
static const int xa_adpcm_table[5][2] = { 
   {   0,   0 }, 
   {  60,   0 }, 
   { 115, -52 }, 
   {  98, -55 }, 
   { 122, -60 } 
}; 
 
static const int ea_adpcm_table[] = { 
    0, 240, 460, 392, 0, 0, -208, -220, 0, 1, 
    3, 4, 7, 8, 10, 11, 0, -1, -3, -4 
}; 
 
static const int ct_adpcm_table[8] = { 
    0x00E6, 0x00E6, 0x00E6, 0x00E6, 
    0x0133, 0x0199, 0x0200, 0x0266 
}; 
 
// padded to zero where table size is less then 16 
static const int swf_index_tables[4][16] = { 
    /*2*/ { -1, 2 }, 
    /*3*/ { -1, -1, 2, 4 }, 
    /*4*/ { -1, -1, -1, -1, 2, 4, 6, 8 }, 
    /*5*/ { -1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 4, 6, 8, 10, 13, 16 } 
}; 
 
static const int yamaha_indexscale[] = { 
    230, 230, 230, 230, 307, 409, 512, 614, 
    230, 230, 230, 230, 307, 409, 512, 614 
}; 
 
static const int yamaha_difflookup[] = { 
    1, 3, 5, 7, 9, 11, 13, 15, 
    -1, -3, -5, -7, -9, -11, -13, -15 
}; 
 
/* end of tables */ 
 
typedef struct ADPCMChannelStatus { 
    int predictor; 
    short int step_index; 
    int step; 
    /* for encoding */ 
    int prev_sample; 
 
    /* MS version */ 
    short sample1; 
    short sample2; 
    int coeff1; 
    int coeff2; 
    int idelta; 
} ADPCMChannelStatus; 
 
typedef struct ADPCMContext { 
    int channel; /* for stereo MOVs, decode left, then decode right, then tell it's decoded */ 
    ADPCMChannelStatus status[2]; 
    short sample_buffer[32]; /* hold left samples while waiting for right samples */ 
 
    /* SWF only */ 
    int nb_bits; 
    int nb_samples; 
} ADPCMContext; 
 
/* XXX: implement encoding */ 
 
#ifdef CONFIG_ENCODERS 
static int adpcm_encode_init(AVCodecContext *avctx) 
{ 
    if (avctx->channels > 2) 
        return -1; /* only stereo or mono =) */ 
    switch(avctx->codec->id) { 
    case CODEC_ID_ADPCM_IMA_QT: 
        av_log(avctx, AV_LOG_ERROR, "ADPCM: codec adpcm_ima_qt unsupported for encoding !\n"); 
        avctx->frame_size = 64; /* XXX: can multiple of avctx->channels * 64 (left and right blocks are interleaved) */ 
        return -1; 
        break; 
    case CODEC_ID_ADPCM_IMA_WAV: 
        avctx->frame_size = (BLKSIZE - 4 * avctx->channels) * 8 / (4 * avctx->channels) + 1; /* each 16 bits sample gives one nibble */ 
                                                             /* and we have 4 bytes per channel overhead */ 
        avctx->block_align = BLKSIZE; 
        /* seems frame_size isn't taken into account... have to buffer the samples :-( */ 
        break; 
    case CODEC_ID_ADPCM_MS: 
        avctx->frame_size = (BLKSIZE - 7 * avctx->channels) * 2 / avctx->channels + 2; /* each 16 bits sample gives one nibble */ 
                                                             /* and we have 7 bytes per channel overhead */ 
        avctx->block_align = BLKSIZE; 
        break; 
    case CODEC_ID_ADPCM_YAMAHA: 
        avctx->frame_size = BLKSIZE * avctx->channels; 
        avctx->block_align = BLKSIZE; 
        break; 
    default: 
        return -1; 
        break; 
    } 
 
    avctx->coded_frame= avcodec_alloc_frame(); 
    avctx->coded_frame->key_frame= 1; 
 
    return 0; 
} 
 
static int adpcm_encode_close(AVCodecContext *avctx) 
{ 
    av_freep(&avctx->coded_frame); 
 
    return 0; 
} 
 
 
static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, short sample) 
{ 
    int step_index; 
    unsigned char nibble; 
 
    int sign = 0; /* sign bit of the nibble (MSB) */ 
    int delta, predicted_delta; 
 
    delta = sample - c->prev_sample; 
 
    if (delta < 0) { 
        sign = 1; 
        delta = -delta; 
    } 
 
    step_index = c->step_index; 
 
    /* nibble = 4 * delta / step_table[step_index]; */ 
    nibble = (delta << 2) / step_table[step_index]; 
 
    if (nibble > 7) 
        nibble = 7; 
 
    step_index += index_table[nibble]; 
    if (step_index < 0) 
        step_index = 0; 
    if (step_index > 88) 
        step_index = 88; 
 
    /* what the decoder will find */ 
    predicted_delta = ((step_table[step_index] * nibble) / 4) + (step_table[step_index] / 8); 
 
    if (sign) 
        c->prev_sample -= predicted_delta; 
    else 
        c->prev_sample += predicted_delta; 
 
    CLAMP_TO_SHORT(c->prev_sample); 
 
 
    nibble += sign << 3; /* sign * 8 */ 
 
    /* save back */ 
    c->step_index = step_index; 
 
    return nibble; 
} 
 
static inline unsigned char adpcm_ms_compress_sample(ADPCMChannelStatus *c, short sample) 
{ 
    int predictor, nibble, bias; 
 
    predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256; 
 
    nibble= sample - predictor; 
    if(nibble>=0) bias= c->idelta/2; 
    else          bias=-c->idelta/2; 
 
    nibble= (nibble + bias) / c->idelta; 
    nibble= clip(nibble, -8, 7)&0x0F; 
 
    predictor += (signed)((nibble & 0x08)?(nibble - 0x10):(nibble)) * c->idelta; 
    CLAMP_TO_SHORT(predictor); 
 
    c->sample2 = c->sample1; 
    c->sample1 = predictor; 
 
    c->idelta = (AdaptationTable[(int)nibble] * c->idelta) >> 8; 
    if (c->idelta < 16) c->idelta = 16; 
 
    return nibble; 
} 
 
static inline unsigned char adpcm_yamaha_compress_sample(ADPCMChannelStatus *c, short sample) 
{ 
    int i1 = 0, j1; 
 
    if(!c->step) { 
        c->predictor = 0; 
        c->step = 127; 
    } 
    j1 = sample - c->predictor; 
 
    j1 = (j1 * 8) / c->step; 
    i1 = abs(j1) / 2; 
    if (i1 > 7) 
        i1 = 7; 
    if (j1 < 0) 
        i1 += 8; 
 
    c->predictor = c->predictor + ((c->step * yamaha_difflookup[i1]) / 8); 
    CLAMP_TO_SHORT(c->predictor); 
    c->step = (c->step * yamaha_indexscale[i1]) >> 8; 
    c->step = clip(c->step, 127, 24567); 
 
    return i1; 
} 
 
static int adpcm_encode_frame(AVCodecContext *avctx, 
                            unsigned char *frame, int buf_size, void *data) 
{ 
    int n, i, st; 
    short *samples; 
    unsigned char *dst; 
    ADPCMContext *c = avctx->priv_data; 
 
    dst = frame; 
    samples = (short *)data; 
    st= avctx->channels == 2; 
/*    n = (BLKSIZE - 4 * avctx->channels) / (2 * 8 * avctx->channels); */ 
 
    switch(avctx->codec->id) { 
    case CODEC_ID_ADPCM_IMA_QT: /* XXX: can't test until we get .mov writer */ 
        break; 
    case CODEC_ID_ADPCM_IMA_WAV: 
        n = avctx->frame_size / 8; 
            c->status[0].prev_sample = (signed short)samples[0]; /* XXX */ 
/*            c->status[0].step_index = 0; *//* XXX: not sure how to init the state machine */ 
            *dst++ = (c->status[0].prev_sample) & 0xFF; /* little endian */ 
            *dst++ = (c->status[0].prev_sample >> 8) & 0xFF; 
            *dst++ = (unsigned char)c->status[0].step_index; 
            *dst++ = 0; /* unknown */ 
            samples++; 
            if (avctx->channels == 2) { 
                c->status[1].prev_sample = (signed short)samples[1]; 
/*                c->status[1].step_index = 0; */ 
                *dst++ = (c->status[1].prev_sample) & 0xFF; 
                *dst++ = (c->status[1].prev_sample >> 8) & 0xFF; 
                *dst++ = (unsigned char)c->status[1].step_index; 
                *dst++ = 0; 
                samples++; 
            } 
 
            /* stereo: 4 bytes (8 samples) for left, 4 bytes for right, 4 bytes left, ... */ 
            for (; n>0; n--) { 
                *dst = adpcm_ima_compress_sample(&c->status[0], samples[0]) & 0x0F; 
                *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels]) << 4) & 0xF0; 
                dst++; 
                *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 2]) & 0x0F; 
                *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 3]) << 4) & 0xF0; 
                dst++; 
                *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 4]) & 0x0F; 
                *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 5]) << 4) & 0xF0; 
                dst++; 
                *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 6]) & 0x0F; 
                *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 7]) << 4) & 0xF0; 
                dst++; 
                /* right channel */ 
                if (avctx->channels == 2) { 
                    *dst = adpcm_ima_compress_sample(&c->status[1], samples[1]); 
                    *dst |= adpcm_ima_compress_sample(&c->status[1], samples[3]) << 4; 
                    dst++; 
                    *dst = adpcm_ima_compress_sample(&c->status[1], samples[5]); 
                    *dst |= adpcm_ima_compress_sample(&c->status[1], samples[7]) << 4; 
                    dst++; 
                    *dst = adpcm_ima_compress_sample(&c->status[1], samples[9]); 
                    *dst |= adpcm_ima_compress_sample(&c->status[1], samples[11]) << 4; 
                    dst++; 
                    *dst = adpcm_ima_compress_sample(&c->status[1], samples[13]); 
                    *dst |= adpcm_ima_compress_sample(&c->status[1], samples[15]) << 4; 
                    dst++; 
                } 
                samples += 8 * avctx->channels; 
            } 
        break; 
    case CODEC_ID_ADPCM_MS: 
        for(i=0; ichannels; i++){ 
            int predictor=0; 
 
            *dst++ = predictor; 
            c->status[i].coeff1 = AdaptCoeff1[predictor]; 
            c->status[i].coeff2 = AdaptCoeff2[predictor]; 
        } 
        for(i=0; ichannels; i++){ 
            if (c->status[i].idelta < 16) 
                c->status[i].idelta = 16; 
 
            *dst++ = c->status[i].idelta & 0xFF; 
            *dst++ = c->status[i].idelta >> 8; 
        } 
        for(i=0; ichannels; i++){ 
            c->status[i].sample1= *samples++; 
 
            *dst++ = c->status[i].sample1 & 0xFF; 
            *dst++ = c->status[i].sample1 >> 8; 
        } 
        for(i=0; ichannels; i++){ 
            c->status[i].sample2= *samples++; 
 
            *dst++ = c->status[i].sample2 & 0xFF; 
            *dst++ = c->status[i].sample2 >> 8; 
        } 
 
        for(i=7*avctx->channels; iblock_align; i++) { 
            int nibble; 
            nibble = adpcm_ms_compress_sample(&c->status[ 0], *samples++)<<4; 
            nibble|= adpcm_ms_compress_sample(&c->status[st], *samples++); 
            *dst++ = nibble; 
        } 
        break; 
    case CODEC_ID_ADPCM_YAMAHA: 
        n = avctx->frame_size / 2; 
        for (; n>0; n--) { 
            for(i = 0; i < avctx->channels; i++) { 
                int nibble; 
                nibble  = adpcm_yamaha_compress_sample(&c->status[i], samples[i]); 
                nibble |= adpcm_yamaha_compress_sample(&c->status[i], samples[i+avctx->channels]) << 4; 
                *dst++ = nibble; 
            } 
            samples += 2 * avctx->channels; 
        } 
        break; 
    default: 
        return -1; 
    } 
    return dst - frame; 
} 
#endif //CONFIG_ENCODERS 
 
static int adpcm_decode_init(AVCodecContext * avctx) 
{ 
    ADPCMContext *c = avctx->priv_data; 
 
    c->channel = 0; 
    c->status[0].predictor = c->status[1].predictor = 0; 
    c->status[0].step_index = c->status[1].step_index = 0; 
    c->status[0].step = c->status[1].step = 0; 
 
    switch(avctx->codec->id) { 
    case CODEC_ID_ADPCM_CT: 
        c->status[0].step = c->status[1].step = 511; 
        break; 
    default: 
        break; 
    } 
    return 0; 
} 
 
static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble, int shift) 
{ 
    int step_index; 
    int predictor; 
    int sign, delta, diff, step; 
 
    step = step_table[c->step_index]; 
    step_index = c->step_index + index_table[(unsigned)nibble]; 
    if (step_index < 0) step_index = 0; 
    else if (step_index > 88) step_index = 88; 
 
    sign = nibble & 8; 
    delta = nibble & 7; 
    /* perform direct multiplication instead of series of jumps proposed by 
     * the reference ADPCM implementation since modern CPUs can do the mults 
     * quickly enough */ 
    diff = ((2 * delta + 1) * step) >> shift; 
    predictor = c->predictor; 
    if (sign) predictor -= diff; 
    else predictor += diff; 
 
    CLAMP_TO_SHORT(predictor); 
    c->predictor = predictor; 
    c->step_index = step_index; 
 
    return (short)predictor; 
} 
 
static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble) 
{ 
    int predictor; 
 
    predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256; 
    predictor += (signed)((nibble & 0x08)?(nibble - 0x10):(nibble)) * c->idelta; 
    CLAMP_TO_SHORT(predictor); 
 
    c->sample2 = c->sample1; 
    c->sample1 = predictor; 
    c->idelta = (AdaptationTable[(int)nibble] * c->idelta) >> 8; 
    if (c->idelta < 16) c->idelta = 16; 
 
    return (short)predictor; 
} 
 
static inline short adpcm_ct_expand_nibble(ADPCMChannelStatus *c, char nibble) 
{ 
    int predictor; 
    int sign, delta, diff; 
    int new_step; 
 
    sign = nibble & 8; 
    delta = nibble & 7; 
    /* perform direct multiplication instead of series of jumps proposed by 
     * the reference ADPCM implementation since modern CPUs can do the mults 
     * quickly enough */ 
    diff = ((2 * delta + 1) * c->step) >> 3; 
    predictor = c->predictor; 
    /* predictor update is not so trivial: predictor is multiplied on 254/256 before updating */ 
    if(sign) 
        predictor = ((predictor * 254) >> 8) - diff; 
    else 
            predictor = ((predictor * 254) >> 8) + diff; 
    /* calculate new step and clamp it to range 511..32767 */ 
    new_step = (ct_adpcm_table[nibble & 7] * c->step) >> 8; 
    c->step = new_step; 
    if(c->step < 511) 
        c->step = 511; 
    if(c->step > 32767) 
        c->step = 32767; 
 
    CLAMP_TO_SHORT(predictor); 
    c->predictor = predictor; 
    return (short)predictor; 
} 
 
static inline short adpcm_sbpro_expand_nibble(ADPCMChannelStatus *c, char nibble, int size, int shift) 
{ 
    int sign, delta, diff; 
 
    sign = nibble & (1<<(size-1)); 
    delta = nibble & ((1<<(size-1))-1); 
    diff = delta << (7 + c->step + shift); 
 
    if (sign) 
        c->predictor -= diff; 
    else 
        c->predictor += diff; 
 
    /* clamp result */ 
    if (c->predictor > 16256) 
        c->predictor = 16256; 
    else if (c->predictor < -16384) 
        c->predictor = -16384; 
 
    /* calculate new step */ 
    if (delta >= (2*size - 3) && c->step < 3) 
        c->step++; 
    else if (delta == 0 && c->step > 0) 
        c->step--; 
 
    return (short) c->predictor; 
} 
 
static inline short adpcm_yamaha_expand_nibble(ADPCMChannelStatus *c, unsigned char nibble) 
{ 
    if(!c->step) { 
        c->predictor = 0; 
        c->step = 127; 
    } 
 
    c->predictor += (c->step * yamaha_difflookup[nibble]) / 8; 
    CLAMP_TO_SHORT(c->predictor); 
    c->step = (c->step * yamaha_indexscale[nibble]) >> 8; 
    c->step = clip(c->step, 127, 24567); 
    return c->predictor; 
} 
 
static void xa_decode(short *out, const unsigned char *in, 
    ADPCMChannelStatus *left, ADPCMChannelStatus *right, int inc) 
{ 
    int i, j; 
    int shift,filter,f0,f1; 
    int s_1,s_2; 
    int d,s,t; 
 
    for(i=0;i<4;i++) { 
 
        shift  = 12 - (in[4+i*2] & 15); 
        filter = in[4+i*2] >> 4; 
        f0 = xa_adpcm_table[filter][0]; 
        f1 = xa_adpcm_table[filter][1]; 
 
        s_1 = left->sample1; 
        s_2 = left->sample2; 
 
        for(j=0;j<28;j++) { 
            d = in[16+i+j*4]; 
 
            t = (signed char)(d<<4)>>4; 
            s = ( t<>6); 
            CLAMP_TO_SHORT(s); 
            *out = s; 
            out += inc; 
            s_2 = s_1; 
            s_1 = s; 
        } 
 
        if (inc==2) { /* stereo */ 
            left->sample1 = s_1; 
            left->sample2 = s_2; 
            s_1 = right->sample1; 
            s_2 = right->sample2; 
            out = out + 1 - 28*2; 
        } 
 
        shift  = 12 - (in[5+i*2] & 15); 
        filter = in[5+i*2] >> 4; 
 
        f0 = xa_adpcm_table[filter][0]; 
        f1 = xa_adpcm_table[filter][1]; 
 
        for(j=0;j<28;j++) { 
            d = in[16+i+j*4]; 
 
            t = (signed char)d >> 4; 
            s = ( t<>6); 
            CLAMP_TO_SHORT(s); 
            *out = s; 
            out += inc; 
            s_2 = s_1; 
            s_1 = s; 
        } 
 
        if (inc==2) { /* stereo */ 
            right->sample1 = s_1; 
            right->sample2 = s_2; 
            out -= 1; 
        } else { 
            left->sample1 = s_1; 
            left->sample2 = s_2; 
        } 
    } 
} 
 
 
/* DK3 ADPCM support macro */ 
#define DK3_GET_NEXT_NIBBLE() \ 
    if (decode_top_nibble_next) \ 
    { \ 
        nibble = (last_byte >> 4) & 0x0F; \ 
        decode_top_nibble_next = 0; \ 
    } \ 
    else \ 
    { \ 
        last_byte = *src++; \ 
        if (src >= buf + buf_size) break; \ 
        nibble = last_byte & 0x0F; \ 
        decode_top_nibble_next = 1; \ 
    } 
 
static int adpcm_decode_frame(AVCodecContext *avctx, 
                            void *data, int *data_size, 
                            uint8_t *buf, int buf_size) 
{ 
    ADPCMContext *c = avctx->priv_data; 
    ADPCMChannelStatus *cs; 
    int n, m, channel, i; 
    int block_predictor[2]; 
    short *samples; 
    uint8_t *src; 
    int st; /* stereo */ 
 
    /* DK3 ADPCM accounting variables */ 
    unsigned char last_byte = 0; 
    unsigned char nibble; 
    int decode_top_nibble_next = 0; 
    int diff_channel; 
 
    /* EA ADPCM state variables */ 
    uint32_t samples_in_chunk; 
    int32_t previous_left_sample, previous_right_sample; 
    int32_t current_left_sample, current_right_sample; 
    int32_t next_left_sample, next_right_sample; 
    int32_t coeff1l, coeff2l, coeff1r, coeff2r; 
    uint8_t shift_left, shift_right; 
    int count1, count2; 
 
    if (!buf_size) 
        return 0; 
 
    samples = data; 
    src = buf; 
 
    st = avctx->channels == 2 ? 1 : 0; 
 
    switch(avctx->codec->id) { 
    case CODEC_ID_ADPCM_IMA_QT: 
        n = (buf_size - 2);/* >> 2*avctx->channels;*/ 
        channel = c->channel; 
        cs = &(c->status[channel]); 
        /* (pppppp) (piiiiiii) */ 
 
        /* Bits 15-7 are the _top_ 9 bits of the 16-bit initial predictor value */ 
        cs->predictor = (*src++) << 8; 
        cs->predictor |= (*src & 0x80); 
        cs->predictor &= 0xFF80; 
 
        /* sign extension */ 
        if(cs->predictor & 0x8000) 
            cs->predictor -= 0x10000; 
 
        CLAMP_TO_SHORT(cs->predictor); 
 
        cs->step_index = (*src++) & 0x7F; 
 
        if (cs->step_index > 88){ 
            av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index); 
            cs->step_index = 88; 
        } 
 
        cs->step = step_table[cs->step_index]; 
 
        if (st && channel) 
            samples++; 
 
        for(m=32; n>0 && m>0; n--, m--) { /* in QuickTime, IMA is encoded by chuncks of 34 bytes (=64 samples) */ 
            *samples = adpcm_ima_expand_nibble(cs, src[0] & 0x0F, 3); 
            samples += avctx->channels; 
            *samples = adpcm_ima_expand_nibble(cs, (src[0] >> 4) & 0x0F, 3); 
            samples += avctx->channels; 
            src ++; 
        } 
 
        if(st) { /* handle stereo interlacing */ 
            c->channel = (channel + 1) % 2; /* we get one packet for left, then one for right data */ 
            if(channel == 1) { /* wait for the other packet before outputing anything */ 
                return src - buf; 
            } 
        } 
        break; 
    case CODEC_ID_ADPCM_IMA_WAV: 
        if (avctx->block_align != 0 && buf_size > avctx->block_align) 
            buf_size = avctx->block_align; 
 
//        samples_per_block= (block_align-4*chanels)*8 / (bits_per_sample * chanels) + 1; 
 
        for(i=0; ichannels; i++){ 
            cs = &(c->status[i]); 
            cs->predictor = (int16_t)(src[0] + (src[1]<<8)); 
            src+=2; 
 
        // XXX: is this correct ??: *samples++ = cs->predictor; 
 
            cs->step_index = *src++; 
            if (cs->step_index > 88){ 
                av_log(avctx, AV_LOG_ERROR, "ERROR: step_index = %i\n", cs->step_index); 
                cs->step_index = 88; 
            } 
            if (*src++) av_log(avctx, AV_LOG_ERROR, "unused byte should be null but is %d!!\n", src[-1]); /* unused */ 
        } 
 
        while(src < buf + buf_size){ 
            for(m=0; m<4; m++){ 
                for(i=0; i<=st; i++) 
                    *samples++ = adpcm_ima_expand_nibble(&c->status[i], src[4*i] & 0x0F, 3); 
                for(i=0; i<=st; i++) 
                    *samples++ = adpcm_ima_expand_nibble(&c->status[i], src[4*i] >> 4  , 3); 
                src++; 
            } 
            src += 4*st; 
        } 
        break; 
    case CODEC_ID_ADPCM_4XM: 
        cs = &(c->status[0]); 
        c->status[0].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2; 
        if(st){ 
            c->status[1].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2; 
        } 
        c->status[0].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2; 
        if(st){ 
            c->status[1].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2; 
        } 
        if (cs->step_index < 0) cs->step_index = 0; 
        if (cs->step_index > 88) cs->step_index = 88; 
 
        m= (buf_size - (src - buf))>>st; 
        for(i=0; istatus[0], src[i] & 0x0F, 4); 
            if (st) 
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[i+m] & 0x0F, 4); 
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[i] >> 4, 4); 
            if (st) 
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[i+m] >> 4, 4); 
        } 
 
        src += m<block_align != 0 && buf_size > avctx->block_align) 
            buf_size = avctx->block_align; 
        n = buf_size - 7 * avctx->channels; 
        if (n < 0) 
            return -1; 
        block_predictor[0] = clip(*src++, 0, 7); 
        block_predictor[1] = 0; 
        if (st) 
            block_predictor[1] = clip(*src++, 0, 7); 
        c->status[0].idelta = (int16_t)((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
        src+=2; 
        if (st){ 
            c->status[1].idelta = (int16_t)((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
            src+=2; 
        } 
        c->status[0].coeff1 = AdaptCoeff1[block_predictor[0]]; 
        c->status[0].coeff2 = AdaptCoeff2[block_predictor[0]]; 
        c->status[1].coeff1 = AdaptCoeff1[block_predictor[1]]; 
        c->status[1].coeff2 = AdaptCoeff2[block_predictor[1]]; 
 
        c->status[0].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
        src+=2; 
        if (st) c->status[1].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
        if (st) src+=2; 
        c->status[0].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
        src+=2; 
        if (st) c->status[1].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00)); 
        if (st) src+=2; 
 
        *samples++ = c->status[0].sample1; 
        if (st) *samples++ = c->status[1].sample1; 
        *samples++ = c->status[0].sample2; 
        if (st) *samples++ = c->status[1].sample2; 
        for(;n>0;n--) { 
            *samples++ = adpcm_ms_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F); 
            *samples++ = adpcm_ms_expand_nibble(&c->status[st], src[0] & 0x0F); 
            src ++; 
        } 
        break; 
    case CODEC_ID_ADPCM_IMA_DK4: 
        if (avctx->block_align != 0 && buf_size > avctx->block_align) 
            buf_size = avctx->block_align; 
 
        c->status[0].predictor = (int16_t)(src[0] | (src[1] << 8)); 
        c->status[0].step_index = src[2]; 
        src += 4; 
        *samples++ = c->status[0].predictor; 
        if (st) { 
            c->status[1].predictor = (int16_t)(src[0] | (src[1] << 8)); 
            c->status[1].step_index = src[2]; 
            src += 4; 
            *samples++ = c->status[1].predictor; 
        } 
        while (src < buf + buf_size) { 
 
            /* take care of the top nibble (always left or mono channel) */ 
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                (src[0] >> 4) & 0x0F, 3); 
 
            /* take care of the bottom nibble, which is right sample for 
             * stereo, or another mono sample */ 
            if (st) 
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
                    src[0] & 0x0F, 3); 
            else 
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F, 3); 
 
            src++; 
        } 
        break; 
    case CODEC_ID_ADPCM_IMA_DK3: 
        if (avctx->block_align != 0 && buf_size > avctx->block_align) 
            buf_size = avctx->block_align; 
 
        c->status[0].predictor = (int16_t)(src[10] | (src[11] << 8)); 
        c->status[1].predictor = (int16_t)(src[12] | (src[13] << 8)); 
        c->status[0].step_index = src[14]; 
        c->status[1].step_index = src[15]; 
        /* sign extend the predictors */ 
        src += 16; 
        diff_channel = c->status[1].predictor; 
 
        /* the DK3_GET_NEXT_NIBBLE macro issues the break statement when 
         * the buffer is consumed */ 
        while (1) { 
 
            /* for this algorithm, c->status[0] is the sum channel and 
             * c->status[1] is the diff channel */ 
 
            /* process the first predictor of the sum channel */ 
            DK3_GET_NEXT_NIBBLE(); 
            adpcm_ima_expand_nibble(&c->status[0], nibble, 3); 
 
            /* process the diff channel predictor */ 
            DK3_GET_NEXT_NIBBLE(); 
            adpcm_ima_expand_nibble(&c->status[1], nibble, 3); 
 
            /* process the first pair of stereo PCM samples */ 
            diff_channel = (diff_channel + c->status[1].predictor) / 2; 
            *samples++ = c->status[0].predictor + c->status[1].predictor; 
            *samples++ = c->status[0].predictor - c->status[1].predictor; 
 
            /* process the second predictor of the sum channel */ 
            DK3_GET_NEXT_NIBBLE(); 
            adpcm_ima_expand_nibble(&c->status[0], nibble, 3); 
 
            /* process the second pair of stereo PCM samples */ 
            diff_channel = (diff_channel + c->status[1].predictor) / 2; 
            *samples++ = c->status[0].predictor + c->status[1].predictor; 
            *samples++ = c->status[0].predictor - c->status[1].predictor; 
        } 
        break; 
    case CODEC_ID_ADPCM_IMA_WS: 
        /* no per-block initialization; just start decoding the data */ 
        while (src < buf + buf_size) { 
 
            if (st) { 
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F, 3); 
                *samples++ = adpcm_ima_expand_nibble(&c->status[1], 
                    src[0] & 0x0F, 3); 
            } else { 
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F, 3); 
                *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                    src[0] & 0x0F, 3); 
            } 
 
            src++; 
        } 
        break; 
    case CODEC_ID_ADPCM_XA: 
        c->status[0].sample1 = c->status[0].sample2 = 
        c->status[1].sample1 = c->status[1].sample2 = 0; 
        while (buf_size >= 128) { 
            xa_decode(samples, src, &c->status[0], &c->status[1], 
                avctx->channels); 
            src += 128; 
            samples += 28 * 8; 
            buf_size -= 128; 
        } 
        break; 
    case CODEC_ID_ADPCM_EA: 
        samples_in_chunk = LE_32(src); 
        if (samples_in_chunk >= ((buf_size - 12) * 2)) { 
            src += buf_size; 
            break; 
        } 
        src += 4; 
        current_left_sample = (int16_t)LE_16(src); 
        src += 2; 
        previous_left_sample = (int16_t)LE_16(src); 
        src += 2; 
        current_right_sample = (int16_t)LE_16(src); 
        src += 2; 
        previous_right_sample = (int16_t)LE_16(src); 
        src += 2; 
 
        for (count1 = 0; count1 < samples_in_chunk/28;count1++) { 
            coeff1l = ea_adpcm_table[(*src >> 4) & 0x0F]; 
            coeff2l = ea_adpcm_table[((*src >> 4) & 0x0F) + 4]; 
            coeff1r = ea_adpcm_table[*src & 0x0F]; 
            coeff2r = ea_adpcm_table[(*src & 0x0F) + 4]; 
            src++; 
 
            shift_left = ((*src >> 4) & 0x0F) + 8; 
            shift_right = (*src & 0x0F) + 8; 
            src++; 
 
            for (count2 = 0; count2 < 28; count2++) { 
                next_left_sample = (((*src & 0xF0) << 24) >> shift_left); 
                next_right_sample = (((*src & 0x0F) << 28) >> shift_right); 
                src++; 
 
                next_left_sample = (next_left_sample + 
                    (current_left_sample * coeff1l) + 
                    (previous_left_sample * coeff2l) + 0x80) >> 8; 
                next_right_sample = (next_right_sample + 
                    (current_right_sample * coeff1r) + 
                    (previous_right_sample * coeff2r) + 0x80) >> 8; 
                CLAMP_TO_SHORT(next_left_sample); 
                CLAMP_TO_SHORT(next_right_sample); 
 
                previous_left_sample = current_left_sample; 
                current_left_sample = next_left_sample; 
                previous_right_sample = current_right_sample; 
                current_right_sample = next_right_sample; 
                *samples++ = (unsigned short)current_left_sample; 
                *samples++ = (unsigned short)current_right_sample; 
            } 
        } 
        break; 
    case CODEC_ID_ADPCM_IMA_SMJPEG: 
        c->status[0].predictor = *src; 
        src += 2; 
        c->status[0].step_index = *src++; 
        src++;  /* skip another byte before getting to the meat */ 
        while (src < buf + buf_size) { 
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                *src & 0x0F, 3); 
            *samples++ = adpcm_ima_expand_nibble(&c->status[0], 
                (*src >> 4) & 0x0F, 3); 
            src++; 
        } 
        break; 
    case CODEC_ID_ADPCM_CT: 
        while (src < buf + buf_size) { 
            if (st) { 
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F); 
                *samples++ = adpcm_ct_expand_nibble(&c->status[1], 
                    src[0] & 0x0F); 
            } else { 
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F); 
                *samples++ = adpcm_ct_expand_nibble(&c->status[0], 
                    src[0] & 0x0F); 
            } 
            src++; 
        } 
        break; 
    case CODEC_ID_ADPCM_SBPRO_4: 
    case CODEC_ID_ADPCM_SBPRO_3: 
    case CODEC_ID_ADPCM_SBPRO_2: 
        if (!c->status[0].step_index) { 
            /* the first byte is a raw sample */ 
            *samples++ = 128 * (*src++ - 0x80); 
            if (st) 
              *samples++ = 128 * (*src++ - 0x80); 
            c->status[0].step_index = 1; 
        } 
        if (avctx->codec->id == CODEC_ID_ADPCM_SBPRO_4) { 
            while (src < buf + buf_size) { 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    (src[0] >> 4) & 0x0F, 4, 0); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st], 
                    src[0] & 0x0F, 4, 0); 
                src++; 
            } 
        } else if (avctx->codec->id == CODEC_ID_ADPCM_SBPRO_3) { 
            while (src < buf + buf_size) { 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    (src[0] >> 5) & 0x07, 3, 0); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    (src[0] >> 2) & 0x07, 3, 0); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    src[0] & 0x03, 2, 0); 
                src++; 
            } 
        } else { 
            while (src < buf + buf_size) { 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    (src[0] >> 6) & 0x03, 2, 2); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st], 
                    (src[0] >> 4) & 0x03, 2, 2); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[0], 
                    (src[0] >> 2) & 0x03, 2, 2); 
                *samples++ = adpcm_sbpro_expand_nibble(&c->status[st], 
                    src[0] & 0x03, 2, 2); 
                src++; 
            } 
        } 
        break; 
    case CODEC_ID_ADPCM_SWF: 
    { 
        GetBitContext gb; 
        const int *table; 
        int k0, signmask; 
        int size = buf_size*8; 
 
        init_get_bits(&gb, buf, size); 
 
        // first frame, read bits & inital values 
        if (!c->nb_bits) 
        { 
            c->nb_bits = get_bits(&gb, 2)+2; 
//            av_log(NULL,AV_LOG_INFO,"nb_bits: %d\n", c->nb_bits); 
        } 
 
        table = swf_index_tables[c->nb_bits-2]; 
        k0 = 1 << (c->nb_bits-2); 
        signmask = 1 << (c->nb_bits-1); 
 
        while (get_bits_count(&gb) <= size) 
        { 
            int i; 
 
            c->nb_samples++; 
            // wrap around at every 4096 samples... 
            if ((c->nb_samples & 0xfff) == 1) 
            { 
                for (i = 0; i <= st; i++) 
                { 
                    *samples++ = c->status[i].predictor = get_sbits(&gb, 16); 
                    c->status[i].step_index = get_bits(&gb, 6); 
                } 
            } 
 
            // similar to IMA adpcm 
            for (i = 0; i <= st; i++) 
            { 
                int delta = get_bits(&gb, c->nb_bits); 
                int step = step_table[c->status[i].step_index]; 
                long vpdiff = 0; // vpdiff = (delta+0.5)*step/4 
                int k = k0; 
 
                do { 
                    if (delta & k) 
                        vpdiff += step; 
                    step >>= 1; 
                    k >>= 1; 
                } while(k); 
                vpdiff += step; 
 
                if (delta & signmask) 
                    c->status[i].predictor -= vpdiff; 
                else 
                    c->status[i].predictor += vpdiff; 
 
                c->status[i].step_index += table[delta & (~signmask)]; 
 
                c->status[i].step_index = clip(c->status[i].step_index, 0, 88); 
                c->status[i].predictor = clip(c->status[i].predictor, -32768, 32767); 
 
                *samples++ = c->status[i].predictor; 
            } 
        } 
 
//        src += get_bits_count(&gb)*8; 
        src += size; 
 
        break; 
    } 
    case CODEC_ID_ADPCM_YAMAHA: 
        while (src < buf + buf_size) { 
            if (st) { 
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0], 
                        src[0] & 0x0F); 
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[1], 
                        (src[0] >> 4) & 0x0F); 
            } else { 
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0], 
                        src[0] & 0x0F); 
                *samples++ = adpcm_yamaha_expand_nibble(&c->status[0], 
                        (src[0] >> 4) & 0x0F); 
            } 
            src++; 
        } 
        break; 
    default: 
        return -1; 
    } 
    *data_size = (uint8_t *)samples - (uint8_t *)data; 
    return src - buf; 
} 
 
 
 
#ifdef CONFIG_ENCODERS 
#define ADPCM_ENCODER(id,name)                  \ 
AVCodec name ## _encoder = {                    \ 
    #name,                                      \ 
    CODEC_TYPE_AUDIO,                           \ 
    id,                                         \ 
    sizeof(ADPCMContext),                       \ 
    adpcm_encode_init,                          \ 
    adpcm_encode_frame,                         \ 
    adpcm_encode_close,                         \ 
    NULL,                                       \ 
}; 
#else 
#define ADPCM_ENCODER(id,name) 
#endif 
 
#ifdef CONFIG_DECODERS 
#define ADPCM_DECODER(id,name)                  \ 
AVCodec name ## _decoder = {                    \ 
    #name,                                      \ 
    CODEC_TYPE_AUDIO,                           \ 
    id,                                         \ 
    sizeof(ADPCMContext),                       \ 
    adpcm_decode_init,                          \ 
    NULL,                                       \ 
    NULL,                                       \ 
    adpcm_decode_frame,                         \ 
}; 
#else 
#define ADPCM_DECODER(id,name) 
#endif 
 
#define ADPCM_CODEC(id, name)                   \ 
ADPCM_ENCODER(id,name) ADPCM_DECODER(id,name) 
 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt); 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav); 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3); 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4); 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WS, adpcm_ima_ws); 
ADPCM_CODEC(CODEC_ID_ADPCM_IMA_SMJPEG, adpcm_ima_smjpeg); 
ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms); 
ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm); 
ADPCM_CODEC(CODEC_ID_ADPCM_XA, adpcm_xa); 
ADPCM_CODEC(CODEC_ID_ADPCM_ADX, adpcm_adx); 
ADPCM_CODEC(CODEC_ID_ADPCM_EA, adpcm_ea); 
ADPCM_CODEC(CODEC_ID_ADPCM_CT, adpcm_ct); 
ADPCM_CODEC(CODEC_ID_ADPCM_SWF, adpcm_swf); 
ADPCM_CODEC(CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha); 
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_4, adpcm_sbpro_4); 
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_3, adpcm_sbpro_3); 
ADPCM_CODEC(CODEC_ID_ADPCM_SBPRO_2, adpcm_sbpro_2); 
 
#undef ADPCM_CODEC