apps/codecs/libffmpegFLAC/decoder.c


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<
  char *dest=s;
  register char *max;
  s+=strlen(s);
  if (__unlikely((max=s+n)==s)) goto fini;
  for (;;) {
    if (__unlikely(!(*s = *t))) break; if (__unlikely(++s==max)) break; ++t;
#ifndef WANT_SMALL_STRING_ROUTINES
    if (__unlikely(!(*s = *t))) break; if (__unlikely(++s==max)) break; ++t;
    if (__unlikely(!(*s = *t))) break; if (__unlikely(++s==max)) break; ++t;
    if (__unlikely(!(*s = *t))) break; if (__unlikely(++s==max)) break; ++t;
#endif
  }
  *s=0;
fini:
  return dest;
}
/*
 * FLAC (Free Lossless Audio Codec) decoder
 * Copyright (c) 2003 Alex Beregszaszi
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/**
 * @file flac.c
 * FLAC (Free Lossless Audio Codec) decoder
 * @author Alex Beregszaszi
 *
 * For more information on the FLAC format, visit:
 *  http://flac.sourceforge.net/
 *
 * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
 * through, starting from the initial 'fLaC' signature; or by passing the
 * 34-byte streaminfo structure through avctx->extradata[_size] followed
 * by data starting with the 0xFFF8 marker.
 */

#include <inttypes.h>
#include <stdbool.h>
#ifndef BUILD_STANDALONE
#include "codeclib.h"
#endif
 
#include "bitstream.h"
#include "golomb.h"

#include "decoder.h"

#if defined(CPU_COLDFIRE)
#include "coldfire.h"
#elif defined(CPU_ARM)
#include "arm.h"
#endif

static const int sample_rate_table[] ICONST_ATTR =
{ 0, 88200, 176400, 192000,
  8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
  0, 0, 0, 0 };

static const int sample_size_table[] ICONST_ATTR = 
{ 0, 8, 12, 0, 16, 20, 24, 0 };

static const int blocksize_table[] ICONST_ATTR = {
     0,    192, 576<<0, 576<<1, 576<<2, 576<<3,      0,      0, 
256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7 
};

static const uint8_t table_crc8[256] ICONST_ATTR = {
    0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15,
    0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d,
    0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
    0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d,
    0xe0, 0xe7, 0xee, 0xe9, 0xfc, 0xfb, 0xf2, 0xf5,
    0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
    0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85,
    0xa8, 0xaf, 0xa6, 0xa1, 0xb4, 0xb3, 0xba, 0xbd,
    0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
    0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea,
    0xb7, 0xb0, 0xb9, 0xbe, 0xab, 0xac, 0xa5, 0xa2,
    0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
    0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32,
    0x1f, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0d, 0x0a,
    0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
    0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a,
    0x89, 0x8e, 0x87, 0x80, 0x95, 0x92, 0x9b, 0x9c,
    0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
    0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec,
    0xc1, 0xc6, 0xcf, 0xc8, 0xdd, 0xda, 0xd3, 0xd4,
    0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
    0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44,
    0x19, 0x1e, 0x17, 0x10, 0x05, 0x02, 0x0b, 0x0c,
    0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
    0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b,
    0x76, 0x71, 0x78, 0x7f, 0x6a, 0x6d, 0x64, 0x63,
    0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
    0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13,
    0xae, 0xa9, 0xa0, 0xa7, 0xb2, 0xb5, 0xbc, 0xbb,
    0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
    0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb,
    0xe6, 0xe1, 0xe8, 0xef, 0xfa, 0xfd, 0xf4, 0xf3
};

static int64_t get_utf8(GetBitContext *gb) ICODE_ATTR_FLAC;
static int64_t get_utf8(GetBitContext *gb)
{
    uint64_t val;
    int ones=0, bytes;
    
    while(get_bits1(gb))
        ones++;

    if     (ones==0) bytes=0;
    else if(ones==1) return -1;
    else             bytes= ones - 1;
    
    val= get_bits(gb, 7-ones);
    while(bytes--){
        const int tmp = get_bits(gb, 8);
        
        if((tmp>>6) != 2)
            return -2;
        val<<=6;
        val|= tmp&0x3F;
    }
    return val;
}

static int get_crc8(const uint8_t *buf, int count) ICODE_ATTR_FLAC;
static int get_crc8(const uint8_t *buf, int count)
{
    int crc=0;
    int i;
    
    for(i=0; i<count; i++){
        crc = table_crc8[crc ^ buf[i]];
    }

    return crc;
}

static int decode_residuals(FLACContext *s, int32_t* decoded, int pred_order) ICODE_ATTR_FLAC;
static int decode_residuals(FLACContext *s, int32_t* decoded, int pred_order)
{
    int i, tmp, partition, method_type, rice_order;
    int sample = 0, samples;

    method_type = get_bits(&s->gb, 2);
    if (method_type > 1){
        //fprintf(stderr,"illegal residual coding method %d\n", method_type);
        return -3;
    }
    
    rice_order = get_bits(&s->gb, 4);

    samples= s->blocksize >> rice_order;

    sample= 
    i= pred_order;
    for (partition = 0; partition < (1 << rice_order); partition++)
    {
        tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
        if (tmp == (method_type == 0 ? 15 : 31))
        {
            //fprintf(stderr,"fixed len partition\n");
            tmp = get_bits(&s->gb, 5);
            for (; i < samples; i++, sample++)
                decoded[sample] = get_sbits(&s->gb, tmp);
        }
        else
        {
            for (; i < samples; i++, sample++){
                decoded[sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
            }
        }
        i= 0;
    }

    return 0;
}    

static int decode_subframe_fixed(FLACContext *s, int32_t* decoded, int pred_order) ICODE_ATTR_FLAC;
static int decode_subframe_fixed(FLACContext *s, int32_t* decoded, int pred_order)
{
    const int blocksize = s->blocksize;
    int a, b, c, d, i;
        
    /* warm up samples */
    for (i = 0; i < pred_order; i++)
    {
        decoded[i] = get_sbits(&s->gb, s->curr_bps);
    }
    
    if (decode_residuals(s, decoded, pred_order) < 0)
        return -4;

    a = decoded[pred_order-1];
    b = a - decoded[pred_order-2];
    c = b - decoded[pred_order-2] + decoded[pred_order-3];
    d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];

    switch(pred_order)
    {
        case 0:
            break;
        case 1:
            for (i = pred_order; i < blocksize; i++)
                decoded[i] = a += decoded[i];
            break;
        case 2:
            for (i = pred_order; i < blocksize; i++)
                decoded[i] = a += b += decoded[i];
            break;
        case 3:
            for (i = pred_order; i < blocksize; i++)
                decoded[i] = a += b += c += decoded[i];
            break;
        case 4:
            for (i = pred_order; i < blocksize; i++)
                decoded[i] = a += b += c += d += decoded[i];
            break;
        default:
            return -5;
    }

    return 0;
}

static int decode_subframe_lpc(FLACContext *s, int32_t* decoded, int pred_order) ICODE_ATTR_FLAC;
static int decode_subframe_lpc(FLACContext *s, int32_t* decoded, int pred_order)
{
    int sum, i, j;
    int64_t wsum;
    int coeff_prec, qlevel;
    int coeffs[pred_order];

    /* warm up samples */
    for (i = 0; i < pred_order; i++)
    {
        decoded[i] = get_sbits(&s->gb, s->curr_bps);
    }
    
    coeff_prec = get_bits(&s->gb, 4) + 1;
    if (coeff_prec == 16)
    {
        //fprintf(stderr,"invalid coeff precision\n");
        return -6;
    }
    qlevel = get_sbits(&s->gb, 5);
    if (qlevel < 0) 
    {
        //fprintf(stderr,"qlevel %d not supported, maybe buggy stream\n", qlevel);
        return -7;
    }

    for (i = 0; i < pred_order; i++)
    {
        coeffs[i] = get_sbits(&s->gb, coeff_prec);
    }
    
    if (decode_residuals(s, decoded, pred_order) < 0)
        return -8;

    if ((s->bps + coeff_prec + av_log2(pred_order)) <= 32) {
        #if defined(CPU_COLDFIRE)
        (void)sum;
        lpc_decode_emac(s->blocksize - pred_order, qlevel, pred_order,
                        decoded + pred_order, coeffs);
        #elif defined(CPU_ARM)
        (void)sum;
        lpc_decode_arm(s->blocksize - pred_order, qlevel, pred_order,
                       decoded + pred_order, coeffs);
        #else
        for (i = pred_order; i < s->blocksize; i++)
        {
            sum = 0;
            for (j = 0; j < pred_order; j++)
                sum += coeffs[j] * decoded[i-j-1];
            decoded[i] += sum >> qlevel;
        }
        #endif
    } else {
        #if defined(CPU_COLDFIRE)
        (void)wsum;
        (void)j;
        lpc_decode_emac_wide(s->blocksize - pred_order, qlevel, pred_order,
                             decoded + pred_order, coeffs);
        #else
        for (i = pred_order; i < s->blocksize; i++)
        {
            wsum = 0;
            for (j = 0; j < pred_order; j++)
                wsum += (int64_t)coeffs[j] * (int64_t)decoded[i-j-1];
            decoded[i] += wsum >> qlevel;
        }
        #endif
    }
    
    return 0;
}

static inline int decode_subframe(FLACContext *s, int channel, int32_t* decoded)
{
    int type, wasted = 0;
    int i, tmp;
    
    s->curr_bps = s->bps;
    if(channel == 0){
        if(s->decorrelation == RIGHT_SIDE)
            s->curr_bps++;
    }else{
        if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
            s->curr_bps++;
    }

    if (get_bits1(&s->gb))
    {
        //fprintf(stderr,"invalid subframe padding\n");
        return -9;
    }
    type = get_bits(&s->gb, 6);
//    wasted = get_bits1(&s->gb);
    
//    if (wasted)
//    {
//        while (!get_bits1(&s->gb))
//            wasted++;
//        if (wasted)
//            wasted++;
//        s->curr_bps -= wasted;
//    }
#if 0
    wasted= 16 - av_log2(show_bits(&s->gb, 17));
    skip_bits(&s->gb, wasted+1);
    s->curr_bps -= wasted;
#else
    if (get_bits1(&s->gb))
    {
        wasted = 1;
        while (!get_bits1(&s->gb))
            wasted++;
        s->curr_bps -= wasted;
        //fprintf(stderr,"%d wasted bits\n", wasted);
    }
#endif
//FIXME use av_log2 for types
    if (type == 0)
    {
        //fprintf(stderr,"coding type: constant\n");
        tmp = get_sbits(&s->gb, s->curr_bps);
        for (i = 0; i < s->blocksize; i++)
            decoded[i] = tmp;
    }
    else if (type == 1)
    {
        //fprintf(stderr,"coding type: verbatim\n");
        for (i = 0; i < s->blocksize; i++)
            decoded[i] = get_sbits(&s->gb, s->curr_bps);
    }
    else if ((type >= 8) && (type <= 12))
    {
        //fprintf(stderr,"coding type: fixed\n");
        if (decode_subframe_fixed(s, decoded, type & ~0x8) < 0)
            return -10;
    }
    else if (type >= 32)
    {
        //fprintf(stderr,"coding type: lpc\n");
        if (decode_subframe_lpc(s, decoded, (type & ~0x20)+1) < 0)
            return -11;
    }
    else
    {
        //fprintf(stderr,"Unknown coding type: %d\n",type);
        return -12;
    }
        
    if (wasted)
    {
        int i;
        for (i = 0; i < s->blocksize; i++)
            decoded[i] <<= wasted;
    }

    return 0;
}

static int decode_frame(FLACContext *s,
                        void (*yield)(void)) ICODE_ATTR_FLAC;
static int decode_frame(FLACContext *s,
                        void (*yield)(void))
{
    int blocksize_code, sample_rate_code, sample_size_code, assignment, crc8;
    int decorrelation, bps, blocksize, samplerate;
    int res, ch;
    
    blocksize_code = get_bits(&s->gb, 4);

    sample_rate_code = get_bits(&s->gb, 4);
    
    assignment = get_bits(&s->gb, 4); /* channel assignment */
    if (assignment < 8 && s->channels == assignment+1)
        decorrelation = INDEPENDENT;
    else if (assignment >=8 && assignment < 11 && s->channels == 2)
        decorrelation = LEFT_SIDE + assignment - 8;
    else
    {
        return -13;
    }
        
    sample_size_code = get_bits(&s->gb, 3);
    if(sample_size_code == 0)
        bps= s->bps;
    else if((sample_size_code != 3) && (sample_size_code != 7))
        bps = sample_size_table[sample_size_code];
    else 
    {
        return -14;
    }

    if (get_bits1(&s->gb))
    {
        return -15;
    }

    /* Get the samplenumber of the first sample in this block */
    s->samplenumber=get_utf8(&s->gb);

    /* samplenumber actually contains the frame number for streams
       with a constant block size - so we multiply by blocksize to
       get the actual sample number */
    if (s->min_blocksize == s->max_blocksize) {
        s->samplenumber*=s->min_blocksize;
    }

#if 0    
    if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
        (s->min_blocksize != s->max_blocksize)){
    }else{
    }
#endif

    if (blocksize_code == 0)
        blocksize = s->min_blocksize;
    else if (blocksize_code == 6)
        blocksize = get_bits(&s->gb, 8)+1;
    else if (blocksize_code == 7)
        blocksize = get_bits(&s->gb, 16)+1;
    else 
        blocksize = blocksize_table[blocksize_code];

    if(blocksize > s->max_blocksize){
        return -16;
    }

    if (sample_rate_code == 0){
        samplerate= s->samplerate;
    }else if ((sample_rate_code < 12))
        samplerate = sample_rate_table[sample_rate_code];
    else if (sample_rate_code == 12)
        samplerate = get_bits(&s->gb, 8) * 1000;
    else if (sample_rate_code == 13)
        samplerate = get_bits(&s->gb, 16);
    else if (sample_rate_code == 14)
        samplerate = get_bits(&s->gb, 16) * 10;
    else{
        return -17;
    }

    skip_bits(&s->gb, 8);
    crc8= get_crc8(s->gb.buffer, get_bits_count(&s->gb)/8);
    if(crc8){
        return -18;
    }
    
    s->blocksize    = blocksize;
    s->samplerate   = samplerate;
    s->bps          = bps;
    s->decorrelation= decorrelation;

    for (ch=0; ch<s->channels; ++ch) {
        yield();
        if ((res=decode_subframe(s, ch, s->decoded[ch])) < 0)
            return res-100;
    }
    
    yield();
    align_get_bits(&s->gb);

    /* frame footer */
    skip_bits(&s->gb, 16); /* data crc */

    return 0;
}

static int flac_downmix(FLACContext *s) ICODE_ATTR_FLAC;
static int flac_downmix(FLACContext *s)
{
    int32_t *FL, *FR, *FC, *SB, *RL, *RR;
    int32_t *outL = s->decoded[0];
    int32_t *outR = s->decoded[1];
    int i, scale=FLAC_OUTPUT_DEPTH-s->bps;

    switch(s->channels)
    {
        case 3: /* 3.0 channel order: FL FR FC */
            FL = s->decoded[0];
            FR = s->decoded[1];
            FC = s->decoded[2];
            /* LF = 0.66 LF + 0.33 FC
               LR = 0.66 LR + 0.33 FC */
            for (i=0; i<s->blocksize; ++i) {
                int32_t a = *(FL)*2 + *(FC);
                int32_t b = *(FR)*2 + *(FC);
                *outL++ = ((a + (a<<2))>>4) << scale; /* 1/3 ~= 5>>4 */
                *outR++ = ((b + (b<<2))>>4) << scale; /* 1/3 ~= 5>>4 */
                FL++; FR++; FC++;
            }
            break;
        case 4: /* 4.0 channel order: FL FR RL RR */
            FL = s->decoded[0];
            FR = s->decoded[1];
            RL = s->decoded[2];
            RR = s->decoded[3];
            /* LF = 0.50 LF + 0.50 RL + 0.00 RR
               LR = 0.50 LR + 0.00 RL + 0.50 RR */
            for (i=0; i<s->blocksize; ++i) {
                int32_t a = *(FL) + *(RL);
                int32_t b = *(FR) + *(RR);
                *outL++ = (a>>1) << scale;
                *outR++ = (b>>1) << scale;
                FL++; FR++; RL++; RR++;
            }
            break;
        case 5: /* 5.0 channel order: FL FR FC RL RR */
            FL = s->decoded[0];
            FR = s->decoded[1];
            FC = s->decoded[2];
            RL = s->decoded[3];
            RR = s->decoded[4];
            /* LF = 0.40 LF + 0.20 FC + 0.40 RL + 0.00 RR
               LR = 0.40 LR + 0.20 FC + 0.00 RL + 0.40 RR */
            for (i=0; i<s->blocksize; ++i) {
                int32_t a = *(FL)*2 + *(FC) + *(RL)*2;
                int32_t b = *(FR)*2 + *(FC) + *(RR)*2;
                *outL++ = ((a + (a<<1))>>4) << scale; /* 3>>4 ~= 1/5 */
                *outR++ = ((b + (b<<1))>>4) << scale; /* 3>>4 ~= 1/5 */
                FL++; FR++; FC++; RL++; RR++;
            }
            break;
        case 6: /* 5.1 channel order: FL FR FC SUB RL RR */
            FL = s->decoded[0];
            FR = s->decoded[1];
            FC = s->decoded[2];
            SB = s->decoded[3];
            RL = s->decoded[4];
            RR = s->decoded[5];
            /* LF = 0.33 LF + 0.16 SUB + 0.16 FC + 0.33 RL + 0.00 RR
               LR = 0.33 LR + 0.16 SUB + 0.16 FC + 0.00 RL + 0.33 RR */
            for (i=0; i<s->blocksize; ++i) {
                int32_t a = *(FL)*2 + *(SB) + *(FC) + *(RL)*2;
                int32_t b = *(FR)*2 + *(SB) + *(FC) + *(RR)*2;
                *outL++ = ((a + (a<<2))>>5) << scale; /* 5>>5 ~= 1/6 */
                *outR++ = ((b + (b<<2))>>5) << scale; /* 5>>5 ~= 1/6 */
                FL++; FR++; SB++; FC++; RL++; RR++;
            }
            break;
        default: /* 1.0 and 2.0 do not need downmix, other formats unknown. */
            return -501;
            break;
    }
    return 0;
}

int flac_decode_frame(FLACContext *s,
                      uint8_t *buf, int buf_size,
                      void (*yield)(void))
{
    int tmp;
    int i;
    int framesize;
    int scale;

    init_get_bits(&s->gb, buf, buf_size*8);

    tmp = get_bits(&s->gb, 16);
    if ((tmp & 0xFFFE) != 0xFFF8){
        return -41;
    }

    if ((framesize=decode_frame(s,yield)) < 0){
       s->bitstream_size=0;
       s->bitstream_index=0;
       return framesize;
    }

    yield();
    
#define DECORRELATE(left, right)\
             for (i = 0; i < s->blocksize; i++) {\
                int32_t a = s->decoded[0][i];\
                int32_t b = s->decoded[1][i];\
                s->decoded[0][i] = (left)  << scale;\
                s->decoded[1][i] = (right) << scale;\
             }\

    scale=FLAC_OUTPUT_DEPTH-s->bps;
    switch(s->decorrelation)
    {
        case INDEPENDENT:
            if (s->channels <= 2) {
                DECORRELATE(a, b) /* Always decorrelate exactly the two supported channels. */
            } else {
                if ((tmp=flac_downmix(s)) != 0)
                    return tmp;
            }
            break;
        case LEFT_SIDE:
            DECORRELATE(a, a-b)
            break;
        case RIGHT_SIDE:
            DECORRELATE(a+b, b)
            break;
        case MID_SIDE:
            DECORRELATE( (a-=b>>1) + b, a)
            break;
    }

    s->framesize = (get_bits_count(&s->gb)+7)>>3;

    return 0;
}