/*
* The simplest AC3 encoder
- * Copyright (c) 2000 Gerard Lantau.
+ * Copyright (c) 2000 Fabrice Bellard.
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * This file is part of FFmpeg.
*
- * This program is distributed in the hope that it will be useful,
+ * 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 General Public License for more details.
+ * 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 General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * 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 ac3enc.c
+ * The simplest AC3 encoder.
*/
//#define DEBUG
//#define DEBUG_BITALLOC
#include "avcodec.h"
-#include <math.h>
-
-#include "ac3enc.h"
-#include "ac3tab.h"
+#include "bitstream.h"
+#include "crc.h"
+#include "ac3.h"
+
+typedef struct AC3EncodeContext {
+ PutBitContext pb;
+ int nb_channels;
+ int nb_all_channels;
+ int lfe_channel;
+ int bit_rate;
+ unsigned int sample_rate;
+ unsigned int bsid;
+ unsigned int frame_size_min; /* minimum frame size in case rounding is necessary */
+ unsigned int frame_size; /* current frame size in words */
+ unsigned int bits_written;
+ unsigned int samples_written;
+ int halfratecod;
+ unsigned int frmsizecod;
+ unsigned int fscod; /* frequency */
+ unsigned int acmod;
+ int lfe;
+ unsigned int bsmod;
+ short last_samples[AC3_MAX_CHANNELS][256];
+ unsigned int chbwcod[AC3_MAX_CHANNELS];
+ int nb_coefs[AC3_MAX_CHANNELS];
+
+ /* bitrate allocation control */
+ int sgaincod, sdecaycod, fdecaycod, dbkneecod, floorcod;
+ AC3BitAllocParameters bit_alloc;
+ int csnroffst;
+ int fgaincod[AC3_MAX_CHANNELS];
+ int fsnroffst[AC3_MAX_CHANNELS];
+ /* mantissa encoding */
+ int mant1_cnt, mant2_cnt, mant4_cnt;
+} AC3EncodeContext;
+static int16_t costab[64];
+static int16_t sintab[64];
+static int16_t fft_rev[512];
+static int16_t xcos1[128];
+static int16_t xsin1[128];
#define MDCT_NBITS 9
#define N (1 << MDCT_NBITS)
-#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
/* new exponents are sent if their Norm 1 exceed this number */
#define EXP_DIFF_THRESHOLD 1000
-/* exponent encoding strategy */
-#define EXP_REUSE 0
-#define EXP_NEW 1
-
-#define EXP_D15 1
-#define EXP_D25 2
-#define EXP_D45 3
-
static void fft_init(int ln);
-static void ac3_crc_init(void);
-static inline INT16 fix15(float a)
+static inline int16_t fix15(float a)
{
int v;
v = (int)(a * (float)(1 << 15));
if (v < -32767)
v = -32767;
- else if (v > 32767)
+ else if (v > 32767)
v = 32767;
return v;
}
-static inline int calc_lowcomp1(int a, int b0, int b1)
-{
- if ((b0 + 256) == b1) {
- a = 384 ;
- } else if (b0 > b1) {
- a = a - 64;
- if (a < 0) a=0;
- }
- return a;
-}
-
-static inline int calc_lowcomp(int a, int b0, int b1, int bin)
-{
- if (bin < 7) {
- if ((b0 + 256) == b1) {
- a = 384 ;
- } else if (b0 > b1) {
- a = a - 64;
- if (a < 0) a=0;
- }
- } else if (bin < 20) {
- if ((b0 + 256) == b1) {
- a = 320 ;
- } else if (b0 > b1) {
- a= a - 64;
- if (a < 0) a=0;
- }
- } else {
- a = a - 128;
- if (a < 0) a=0;
- }
- return a;
-}
-
-/* AC3 bit allocation. The algorithm is the one described in the AC3
- spec with some optimizations because of our simplified encoding
- assumptions. */
-void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
- INT8 *exp, int start, int end,
- int snroffset, int fgain)
-{
- int bin,i,j,k,end1,v,v1,bndstrt,bndend,lowcomp,begin;
- int fastleak,slowleak,address,tmp;
- INT16 psd[256]; /* scaled exponents */
- INT16 bndpsd[50]; /* interpolated exponents */
- INT16 excite[50]; /* excitation */
- INT16 mask[50]; /* masking value */
-
- /* exponent mapping to PSD */
- for(bin=start;bin<end;bin++) {
- psd[bin]=(3072 - (exp[bin] << 7));
- }
-
- /* PSD integration */
- j=start;
- k=masktab[start];
- do {
- v=psd[j];
- j++;
- end1=bndtab[k+1];
- if (end1 > end) end1=end;
- for(i=j;i<end1;i++) {
- int c,adr;
- /* logadd */
- v1=psd[j];
- c=v-v1;
- if (c >= 0) {
- adr=c >> 1;
- if (adr > 255) adr=255;
- v=v + latab[adr];
- } else {
- adr=(-c) >> 1;
- if (adr > 255) adr=255;
- v=v1 + latab[adr];
- }
- j++;
- }
- bndpsd[k]=v;
- k++;
- } while (end > bndtab[k]);
-
- /* excitation function */
- bndstrt = masktab[start];
- bndend = masktab[end-1] + 1;
-
- lowcomp = 0;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1]) ;
- excite[0] = bndpsd[0] - fgain - lowcomp ;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2]) ;
- excite[1] = bndpsd[1] - fgain - lowcomp ;
- begin = 7 ;
- for (bin = 2; bin < 7; bin++) {
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1]) ;
- fastleak = bndpsd[bin] - fgain ;
- slowleak = bndpsd[bin] - s->sgain ;
- excite[bin] = fastleak - lowcomp ;
- if (bndpsd[bin] <= bndpsd[bin+1]) {
- begin = bin + 1 ;
- break ;
- }
- }
-
- end1=bndend;
- if (end1 > 22) end1=22;
-
- for (bin = begin; bin < end1; bin++) {
- lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin) ;
-
- fastleak -= s->fdecay ;
- v = bndpsd[bin] - fgain;
- if (fastleak < v) fastleak = v;
-
- slowleak -= s->sdecay ;
- v = bndpsd[bin] - s->sgain;
- if (slowleak < v) slowleak = v;
-
- v=fastleak - lowcomp;
- if (slowleak > v) v=slowleak;
-
- excite[bin] = v;
- }
-
- for (bin = 22; bin < bndend; bin++) {
- fastleak -= s->fdecay ;
- v = bndpsd[bin] - fgain;
- if (fastleak < v) fastleak = v;
- slowleak -= s->sdecay ;
- v = bndpsd[bin] - s->sgain;
- if (slowleak < v) slowleak = v;
-
- v=fastleak;
- if (slowleak > v) v = slowleak;
- excite[bin] = v;
- }
-
- /* compute masking curve */
-
- for (bin = bndstrt; bin < bndend; bin++) {
- v1 = excite[bin];
- tmp = s->dbknee - bndpsd[bin];
- if (tmp > 0) {
- v1 += tmp >> 2;
- }
- v=hth[bin >> s->halfratecod][s->fscod];
- if (v1 > v) v=v1;
- mask[bin] = v;
- }
-
- /* compute bit allocation */
-
- i = start ;
- j = masktab[start] ;
- do {
- v=mask[j];
- v -= snroffset ;
- v -= s->floor ;
- if (v < 0) v = 0;
- v &= 0x1fe0 ;
- v += s->floor ;
-
- end1=bndtab[j] + bndsz[j];
- if (end1 > end) end1=end;
-
- for (k = i; k < end1; k++) {
- address = (psd[i] - v) >> 5 ;
- if (address < 0) address=0;
- else if (address > 63) address=63;
- bap[i] = baptab[address];
- i++;
- }
- } while (end > bndtab[j++]) ;
-}
-
typedef struct IComplex {
short re,im;
} IComplex;
/* do a 2^n point complex fft on 2^ln points. */
static void fft(IComplex *z, int ln)
{
- int j, l, np, np2;
- int nblocks, nloops;
+ int j, l, np, np2;
+ int nblocks, nloops;
register IComplex *p,*q;
int tmp_re, tmp_im;
p=&z[0];
j=(np >> 1);
do {
- BF(p[0].re, p[0].im, p[1].re, p[1].im,
+ BF(p[0].re, p[0].im, p[1].re, p[1].im,
p[0].re, p[0].im, p[1].re, p[1].im);
p+=2;
} while (--j != 0);
p=&z[0];
j=np >> 2;
do {
- BF(p[0].re, p[0].im, p[2].re, p[2].im,
+ BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
- BF(p[1].re, p[1].im, p[3].re, p[3].im,
+ BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, p[3].im, -p[3].re);
p+=4;
} while (--j != 0);
BF(p->re, p->im, q->re, q->im,
p->re, p->im, q->re, q->im);
-
+
p++;
q++;
for(l = nblocks; l < np2; l += nblocks) {
}
/* do a 512 point mdct */
-static void mdct512(INT32 *out, INT16 *in)
+static void mdct512(int32_t *out, int16_t *in)
{
int i, re, im, re1, im1;
- INT16 rot[N];
+ int16_t rot[N];
IComplex x[N/4];
/* shift to simplify computations */
rot[i] = -in[i + 3*N/4];
for(i=N/4;i<N;i++)
rot[i] = in[i - N/4];
-
+
/* pre rotation */
for(i=0;i<N/4;i++) {
re = ((int)rot[2*i] - (int)rot[N-1-2*i]) >> 1;
}
fft(x, MDCT_NBITS - 2);
-
+
/* post rotation */
for(i=0;i<N/4;i++) {
re = x[i].re;
}
/* XXX: use another norm ? */
-static int calc_exp_diff(UINT8 *exp1, UINT8 *exp2, int n)
+static int calc_exp_diff(uint8_t *exp1, uint8_t *exp2, int n)
{
int sum, i;
sum = 0;
return sum;
}
-static void compute_exp_strategy(UINT8 exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
- UINT8 exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
- int ch)
+static void compute_exp_strategy(uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
+ uint8_t exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ int ch, int is_lfe)
{
int i, j;
int exp_diff;
-
+
/* estimate if the exponent variation & decide if they should be
reused in the next frame */
exp_strategy[0][ch] = EXP_NEW;
for(i=1;i<NB_BLOCKS;i++) {
exp_diff = calc_exp_diff(exp[i][ch], exp[i-1][ch], N/2);
-#ifdef DEBUG
- printf("exp_diff=%d\n", exp_diff);
+#ifdef DEBUG
+ av_log(NULL, AV_LOG_DEBUG, "exp_diff=%d\n", exp_diff);
#endif
if (exp_diff > EXP_DIFF_THRESHOLD)
exp_strategy[i][ch] = EXP_NEW;
else
exp_strategy[i][ch] = EXP_REUSE;
}
+ if (is_lfe)
+ return;
+
/* now select the encoding strategy type : if exponents are often
recoded, we use a coarse encoding */
i = 0;
}
/* set exp[i] to min(exp[i], exp1[i]) */
-static void exponent_min(UINT8 exp[N/2], UINT8 exp1[N/2], int n)
+static void exponent_min(uint8_t exp[N/2], uint8_t exp1[N/2], int n)
{
int i;
exp[i] = exp1[i];
}
}
-
+
/* update the exponents so that they are the ones the decoder will
decode. Return the number of bits used to code the exponents */
-static int encode_exp(UINT8 encoded_exp[N/2],
- UINT8 exp[N/2],
+static int encode_exp(uint8_t encoded_exp[N/2],
+ uint8_t exp[N/2],
int nb_exps,
int exp_strategy)
{
- int group_size, nb_groups, i, j, k, recurse, exp_min, delta;
- UINT8 exp1[N/2];
+ int group_size, nb_groups, i, j, k, exp_min;
+ uint8_t exp1[N/2];
switch(exp_strategy) {
case EXP_D15:
if (exp1[0] > 15)
exp1[0] = 15;
- /* Iterate until the delta constraints between each groups are
- satisfyed. I'm sure it is possible to find a better algorithm,
- but I am lazy */
- do {
- recurse = 0;
- for(i=1;i<=nb_groups;i++) {
- delta = exp1[i] - exp1[i-1];
- if (delta > 2) {
- /* if delta too big, we encode a smaller exponent */
- exp1[i] = exp1[i-1] + 2;
- } else if (delta < -2) {
- /* if delta is too small, we must decrease the previous
- exponent, which means we must recurse */
- recurse = 1;
- exp1[i-1] = exp1[i] + 2;
- }
- }
- } while (recurse);
-
+ /* Decrease the delta between each groups to within 2
+ * so that they can be differentially encoded */
+ for (i=1;i<=nb_groups;i++)
+ exp1[i] = FFMIN(exp1[i], exp1[i-1] + 2);
+ for (i=nb_groups-1;i>=0;i--)
+ exp1[i] = FFMIN(exp1[i], exp1[i+1] + 2);
+
/* now we have the exponent values the decoder will see */
encoded_exp[0] = exp1[0];
k = 1;
}
k += group_size;
}
-
+
#if defined(DEBUG)
- printf("exponents: strategy=%d\n", exp_strategy);
+ av_log(NULL, AV_LOG_DEBUG, "exponents: strategy=%d\n", exp_strategy);
for(i=0;i<=nb_groups * group_size;i++) {
- printf("%d ", encoded_exp[i]);
+ av_log(NULL, AV_LOG_DEBUG, "%d ", encoded_exp[i]);
}
- printf("\n");
+ av_log(NULL, AV_LOG_DEBUG, "\n");
#endif
return 4 + (nb_groups / 3) * 7;
}
/* return the size in bits taken by the mantissa */
-int compute_mantissa_size(AC3EncodeContext *s, UINT8 *m, int nb_coefs)
+static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
{
int bits, mant, i;
break;
case 1:
/* 3 mantissa in 5 bits */
- if (s->mant1_cnt == 0)
+ if (s->mant1_cnt == 0)
bits += 5;
if (++s->mant1_cnt == 3)
s->mant1_cnt = 0;
break;
case 2:
/* 3 mantissa in 7 bits */
- if (s->mant2_cnt == 0)
+ if (s->mant2_cnt == 0)
bits += 7;
if (++s->mant2_cnt == 3)
s->mant2_cnt = 0;
/* 2 mantissa in 7 bits */
if (s->mant4_cnt == 0)
bits += 7;
- if (++s->mant4_cnt == 2)
+ if (++s->mant4_cnt == 2)
s->mant4_cnt = 0;
break;
case 14:
}
+static void bit_alloc_masking(AC3EncodeContext *s,
+ uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
+ int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50])
+{
+ int blk, ch;
+ int16_t bndpsd[NB_BLOCKS][AC3_MAX_CHANNELS][50];
+
+ for(blk=0; blk<NB_BLOCKS; blk++) {
+ for(ch=0;ch<s->nb_all_channels;ch++) {
+ if(exp_strategy[blk][ch] == EXP_REUSE) {
+ memcpy(psd[blk][ch], psd[blk-1][ch], (N/2)*sizeof(int16_t));
+ memcpy(mask[blk][ch], mask[blk-1][ch], 50*sizeof(int16_t));
+ } else {
+ ff_ac3_bit_alloc_calc_psd(encoded_exp[blk][ch], 0,
+ s->nb_coefs[ch],
+ psd[blk][ch], bndpsd[blk][ch]);
+ ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, bndpsd[blk][ch],
+ 0, s->nb_coefs[ch],
+ ff_fgaintab[s->fgaincod[ch]],
+ ch == s->lfe_channel,
+ DBA_NONE, 0, NULL, NULL, NULL,
+ mask[blk][ch]);
+ }
+ }
+ }
+}
+
static int bit_alloc(AC3EncodeContext *s,
- UINT8 bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
- UINT8 encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
- UINT8 exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
+ int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50],
+ int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
int frame_bits, int csnroffst, int fsnroffst)
{
int i, ch;
+ int snroffset;
+
+ snroffset = (((csnroffst - 15) << 4) + fsnroffst) << 2;
/* compute size */
for(i=0;i<NB_BLOCKS;i++) {
s->mant1_cnt = 0;
s->mant2_cnt = 0;
s->mant4_cnt = 0;
- for(ch=0;ch<s->nb_channels;ch++) {
- parametric_bit_allocation(s, bap[i][ch], (INT8 *)encoded_exp[i][ch],
- 0, s->nb_coefs[ch],
- (((csnroffst-15) << 4) +
- fsnroffst) << 2,
- fgaintab[s->fgaincod[ch]]);
- frame_bits += compute_mantissa_size(s, bap[i][ch],
+ for(ch=0;ch<s->nb_all_channels;ch++) {
+ ff_ac3_bit_alloc_calc_bap(mask[i][ch], psd[i][ch], 0,
+ s->nb_coefs[ch], snroffset,
+ s->bit_alloc.floor, bap[i][ch]);
+ frame_bits += compute_mantissa_size(s, bap[i][ch],
s->nb_coefs[ch]);
}
}
#if 0
- printf("csnr=%d fsnr=%d frame_bits=%d diff=%d\n",
- csnroffst, fsnroffst, frame_bits,
+ printf("csnr=%d fsnr=%d frame_bits=%d diff=%d\n",
+ csnroffst, fsnroffst, frame_bits,
16 * s->frame_size - ((frame_bits + 7) & ~7));
#endif
return 16 * s->frame_size - frame_bits;
#define SNR_INC1 4
static int compute_bit_allocation(AC3EncodeContext *s,
- UINT8 bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
- UINT8 encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
- UINT8 exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
+ uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2],
+ uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS],
int frame_bits)
{
int i, ch;
int csnroffst, fsnroffst;
- UINT8 bap1[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ uint8_t bap1[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ int16_t psd[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ int16_t mask[NB_BLOCKS][AC3_MAX_CHANNELS][50];
+ static int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
/* init default parameters */
s->sdecaycod = 2;
s->sgaincod = 1;
s->dbkneecod = 2;
s->floorcod = 4;
- for(ch=0;ch<s->nb_channels;ch++)
+ for(ch=0;ch<s->nb_all_channels;ch++)
s->fgaincod[ch] = 4;
-
+
/* compute real values */
- s->sdecay = sdecaytab[s->sdecaycod] >> s->halfratecod;
- s->fdecay = fdecaytab[s->fdecaycod] >> s->halfratecod;
- s->sgain = sgaintab[s->sgaincod];
- s->dbknee = dbkneetab[s->dbkneecod];
- s->floor = floortab[s->floorcod];
+ s->bit_alloc.fscod = s->fscod;
+ s->bit_alloc.halfratecod = s->halfratecod;
+ s->bit_alloc.sdecay = ff_sdecaytab[s->sdecaycod] >> s->halfratecod;
+ s->bit_alloc.fdecay = ff_fdecaytab[s->fdecaycod] >> s->halfratecod;
+ s->bit_alloc.sgain = ff_sgaintab[s->sgaincod];
+ s->bit_alloc.dbknee = ff_dbkneetab[s->dbkneecod];
+ s->bit_alloc.floor = ff_floortab[s->floorcod];
/* header size */
frame_bits += 65;
- if (s->acmod == 2)
- frame_bits += 2;
+ // if (s->acmod == 2)
+ // frame_bits += 2;
+ frame_bits += frame_bits_inc[s->acmod];
/* audio blocks */
for(i=0;i<NB_BLOCKS;i++) {
- frame_bits += s->nb_channels * 2 + 2;
- if (s->acmod == 2)
- frame_bits++;
- frame_bits += 2 * s->nb_channels;
+ frame_bits += s->nb_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
+ if (s->acmod == AC3_ACMOD_STEREO) {
+ frame_bits++; /* rematstr */
+ if(i==0) frame_bits += 4;
+ }
+ frame_bits += 2 * s->nb_channels; /* chexpstr[2] * c */
+ if (s->lfe)
+ frame_bits++; /* lfeexpstr */
for(ch=0;ch<s->nb_channels;ch++) {
if (exp_strategy[i][ch] != EXP_REUSE)
- frame_bits += 6 + 2;
+ frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
}
frame_bits++; /* baie */
frame_bits++; /* snr */
}
frame_bits++; /* cplinu for block 0 */
/* bit alloc info */
- frame_bits += 2*4 + 3 + 6 + s->nb_channels * (4 + 3);
+ /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
+ /* csnroffset[6] */
+ /* (fsnoffset[4] + fgaincod[4]) * c */
+ frame_bits += 2*4 + 3 + 6 + s->nb_all_channels * (4 + 3);
+
+ /* auxdatae, crcrsv */
+ frame_bits += 2;
/* CRC */
frame_bits += 16;
+ /* calculate psd and masking curve before doing bit allocation */
+ bit_alloc_masking(s, encoded_exp, exp_strategy, psd, mask);
+
/* now the big work begins : do the bit allocation. Modify the snr
offset until we can pack everything in the requested frame size */
csnroffst = s->csnroffst;
- while (csnroffst >= 0 &&
- bit_alloc(s, bap, encoded_exp, exp_strategy, frame_bits, csnroffst, 0) < 0)
+ while (csnroffst >= 0 &&
+ bit_alloc(s, mask, psd, bap, frame_bits, csnroffst, 0) < 0)
csnroffst -= SNR_INC1;
if (csnroffst < 0) {
- fprintf(stderr, "Error !!!\n");
+ av_log(NULL, AV_LOG_ERROR, "Bit allocation failed, try increasing the bitrate, -ab 384 for example!\n");
return -1;
}
- while ((csnroffst + SNR_INC1) <= 63 &&
- bit_alloc(s, bap1, encoded_exp, exp_strategy, frame_bits,
+ while ((csnroffst + SNR_INC1) <= 63 &&
+ bit_alloc(s, mask, psd, bap1, frame_bits,
csnroffst + SNR_INC1, 0) >= 0) {
csnroffst += SNR_INC1;
memcpy(bap, bap1, sizeof(bap1));
}
- while ((csnroffst + 1) <= 63 &&
- bit_alloc(s, bap1, encoded_exp, exp_strategy, frame_bits, csnroffst + 1, 0) >= 0) {
+ while ((csnroffst + 1) <= 63 &&
+ bit_alloc(s, mask, psd, bap1, frame_bits, csnroffst + 1, 0) >= 0) {
csnroffst++;
memcpy(bap, bap1, sizeof(bap1));
}
fsnroffst = 0;
- while ((fsnroffst + SNR_INC1) <= 15 &&
- bit_alloc(s, bap1, encoded_exp, exp_strategy, frame_bits,
+ while ((fsnroffst + SNR_INC1) <= 15 &&
+ bit_alloc(s, mask, psd, bap1, frame_bits,
csnroffst, fsnroffst + SNR_INC1) >= 0) {
fsnroffst += SNR_INC1;
memcpy(bap, bap1, sizeof(bap1));
}
- while ((fsnroffst + 1) <= 15 &&
- bit_alloc(s, bap1, encoded_exp, exp_strategy, frame_bits,
+ while ((fsnroffst + 1) <= 15 &&
+ bit_alloc(s, mask, psd, bap1, frame_bits,
csnroffst, fsnroffst + 1) >= 0) {
fsnroffst++;
memcpy(bap, bap1, sizeof(bap1));
}
-
+
s->csnroffst = csnroffst;
- for(ch=0;ch<s->nb_channels;ch++)
+ for(ch=0;ch<s->nb_all_channels;ch++)
s->fsnroffst[ch] = fsnroffst;
#if defined(DEBUG_BITALLOC)
{
int j;
for(i=0;i<6;i++) {
- for(ch=0;ch<s->nb_channels;ch++) {
+ for(ch=0;ch<s->nb_all_channels;ch++) {
printf("Block #%d Ch%d:\n", i, ch);
printf("bap=");
for(j=0;j<s->nb_coefs[ch];j++) {
int bitrate = avctx->bit_rate;
int channels = avctx->channels;
AC3EncodeContext *s = avctx->priv_data;
- int i, j, k, l, ch, v;
+ int i, j, ch;
float alpha;
- static unsigned short freqs[3] = { 48000, 44100, 32000 };
+ static const uint8_t acmod_defs[6] = {
+ 0x01, /* C */
+ 0x02, /* L R */
+ 0x03, /* L C R */
+ 0x06, /* L R SL SR */
+ 0x07, /* L C R SL SR */
+ 0x07, /* L C R SL SR (+LFE) */
+ };
avctx->frame_size = AC3_FRAME_SIZE;
- avctx->key_frame = 1; /* always key frame */
-
+
+ ac3_common_init();
+
/* number of channels */
- if (channels == 1)
- s->acmod = 1;
- else if (channels == 2)
- s->acmod = 2;
- else
+ if (channels < 1 || channels > 6)
return -1;
- s->nb_channels = channels;
+ s->acmod = acmod_defs[channels - 1];
+ s->lfe = (channels == 6) ? 1 : 0;
+ s->nb_all_channels = channels;
+ s->nb_channels = channels > 5 ? 5 : channels;
+ s->lfe_channel = s->lfe ? 5 : -1;
/* frequency */
for(i=0;i<3;i++) {
- for(j=0;j<3;j++)
- if ((freqs[j] >> i) == freq)
+ for(j=0;j<3;j++)
+ if ((ff_ac3_freqs[j] >> i) == freq)
goto found;
}
return -1;
- found:
+ found:
s->sample_rate = freq;
s->halfratecod = i;
s->fscod = j;
/* bitrate & frame size */
bitrate /= 1000;
for(i=0;i<19;i++) {
- if ((bitratetab[i] >> s->halfratecod) == bitrate)
+ if ((ff_ac3_bitratetab[i] >> s->halfratecod) == bitrate)
break;
}
if (i == 19)
return -1;
s->bit_rate = bitrate;
s->frmsizecod = i << 1;
- s->frame_size_min = (bitrate * 1000 * AC3_FRAME_SIZE) / (freq * 16);
- /* for now we do not handle fractional sizes */
+ s->frame_size_min = ff_ac3_frame_sizes[s->frmsizecod][s->fscod];
+ s->bits_written = 0;
+ s->samples_written = 0;
s->frame_size = s->frame_size_min;
-
+
/* bit allocation init */
for(ch=0;ch<s->nb_channels;ch++) {
/* bandwidth for each channel */
s->chbwcod[ch] = 50; /* sample bandwidth as mpeg audio layer 2 table 0 */
s->nb_coefs[ch] = ((s->chbwcod[ch] + 12) * 3) + 37;
}
+ if (s->lfe) {
+ s->nb_coefs[s->lfe_channel] = 7; /* fixed */
+ }
/* initial snr offset */
s->csnroffst = 40;
- /* compute bndtab and masktab from bandsz */
- k = 0;
- l = 0;
- for(i=0;i<50;i++) {
- bndtab[i] = l;
- v = bndsz[i];
- for(j=0;j<v;j++) masktab[k++]=i;
- l += v;
- }
- bndtab[50] = 0;
-
/* mdct init */
fft_init(MDCT_NBITS - 2);
for(i=0;i<N/4;i++) {
xsin1[i] = fix15(-sin(alpha));
}
- ac3_crc_init();
+ avctx->coded_frame= avcodec_alloc_frame();
+ avctx->coded_frame->key_frame= 1;
return 0;
}
/* output the AC3 frame header */
static void output_frame_header(AC3EncodeContext *s, unsigned char *frame)
{
- init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE, NULL, NULL);
+ init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
put_bits(&s->pb, 16, 0x0b77); /* frame header */
put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
put_bits(&s->pb, 5, s->bsid);
put_bits(&s->pb, 3, s->bsmod);
put_bits(&s->pb, 3, s->acmod);
- if (s->acmod == 2) {
+ if ((s->acmod & 0x01) && s->acmod != AC3_ACMOD_MONO)
+ put_bits(&s->pb, 2, 1); /* XXX -4.5 dB */
+ if (s->acmod & 0x04)
+ put_bits(&s->pb, 2, 1); /* XXX -6 dB */
+ if (s->acmod == AC3_ACMOD_STEREO)
put_bits(&s->pb, 2, 0); /* surround not indicated */
- }
- put_bits(&s->pb, 1, 0); /* no LFE */
+ put_bits(&s->pb, 1, s->lfe); /* LFE */
put_bits(&s->pb, 5, 31); /* dialog norm: -31 db */
put_bits(&s->pb, 1, 0); /* no compression control word */
put_bits(&s->pb, 1, 0); /* no lang code */
int v;
if (c >= 0) {
- v = (levels * (c << e)) >> 25;
+ v = (levels * (c << e)) >> 24;
+ v = (v + 1) >> 1;
v = (levels >> 1) + v;
} else {
- v = (levels * ((-c) << e)) >> 25;
+ v = (levels * ((-c) << e)) >> 24;
+ v = (v + 1) >> 1;
v = (levels >> 1) - v;
}
assert (v >= 0 && v < levels);
/* Output one audio block. There are NB_BLOCKS audio blocks in one AC3
frame */
static void output_audio_block(AC3EncodeContext *s,
- UINT8 exp_strategy[AC3_MAX_CHANNELS],
- UINT8 encoded_exp[AC3_MAX_CHANNELS][N/2],
- UINT8 bap[AC3_MAX_CHANNELS][N/2],
- INT32 mdct_coefs[AC3_MAX_CHANNELS][N/2],
- INT8 global_exp[AC3_MAX_CHANNELS],
+ uint8_t exp_strategy[AC3_MAX_CHANNELS],
+ uint8_t encoded_exp[AC3_MAX_CHANNELS][N/2],
+ uint8_t bap[AC3_MAX_CHANNELS][N/2],
+ int32_t mdct_coefs[AC3_MAX_CHANNELS][N/2],
+ int8_t global_exp[AC3_MAX_CHANNELS],
int block_num)
{
- int ch, nb_groups, group_size, i, baie;
- UINT8 *p;
- UINT16 qmant[AC3_MAX_CHANNELS][N/2];
+ int ch, nb_groups, group_size, i, baie, rbnd;
+ uint8_t *p;
+ uint16_t qmant[AC3_MAX_CHANNELS][N/2];
int exp0, exp1;
int mant1_cnt, mant2_cnt, mant4_cnt;
- UINT16 *qmant1_ptr, *qmant2_ptr, *qmant4_ptr;
+ uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr;
int delta0, delta1, delta2;
- for(ch=0;ch<s->nb_channels;ch++)
+ for(ch=0;ch<s->nb_channels;ch++)
put_bits(&s->pb, 1, 0); /* 512 point MDCT */
- for(ch=0;ch<s->nb_channels;ch++)
+ for(ch=0;ch<s->nb_channels;ch++)
put_bits(&s->pb, 1, 1); /* no dither */
put_bits(&s->pb, 1, 0); /* no dynamic range */
if (block_num == 0) {
put_bits(&s->pb, 1, 0); /* no new coupling strategy */
}
- if (s->acmod == 2) {
- put_bits(&s->pb, 1, 0); /* no matrixing (but should be used in the future) */
- }
+ if (s->acmod == AC3_ACMOD_STEREO)
+ {
+ if(block_num==0)
+ {
+ /* first block must define rematrixing (rematstr) */
+ put_bits(&s->pb, 1, 1);
+
+ /* dummy rematrixing rematflg(1:4)=0 */
+ for (rbnd=0;rbnd<4;rbnd++)
+ put_bits(&s->pb, 1, 0);
+ }
+ else
+ {
+ /* no matrixing (but should be used in the future) */
+ put_bits(&s->pb, 1, 0);
+ }
+ }
-#if defined(DEBUG)
+#if defined(DEBUG)
{
- static int count = 0;
- printf("Block #%d (%d)\n", block_num, count++);
+ static int count = 0;
+ av_log(NULL, AV_LOG_DEBUG, "Block #%d (%d)\n", block_num, count++);
}
#endif
/* exponent strategy */
for(ch=0;ch<s->nb_channels;ch++) {
put_bits(&s->pb, 2, exp_strategy[ch]);
}
-
+
+ if (s->lfe) {
+ put_bits(&s->pb, 1, exp_strategy[s->lfe_channel]);
+ }
+
for(ch=0;ch<s->nb_channels;ch++) {
if (exp_strategy[ch] != EXP_REUSE)
put_bits(&s->pb, 6, s->chbwcod[ch]);
}
-
+
/* exponents */
- for (ch = 0; ch < s->nb_channels; ch++) {
+ for (ch = 0; ch < s->nb_all_channels; ch++) {
switch(exp_strategy[ch]) {
case EXP_REUSE:
continue;
put_bits(&s->pb, 7, ((delta0 * 5 + delta1) * 5) + delta2);
}
- put_bits(&s->pb, 2, 0); /* no gain range info */
+ if (ch != s->lfe_channel)
+ put_bits(&s->pb, 2, 0); /* no gain range info */
}
/* bit allocation info */
put_bits(&s->pb, 1, baie); /* always present with bai */
if (baie) {
put_bits(&s->pb, 6, s->csnroffst);
- for(ch=0;ch<s->nb_channels;ch++) {
+ for(ch=0;ch<s->nb_all_channels;ch++) {
put_bits(&s->pb, 4, s->fsnroffst[ch]);
put_bits(&s->pb, 3, s->fgaincod[ch]);
}
}
-
+
put_bits(&s->pb, 1, 0); /* no delta bit allocation */
put_bits(&s->pb, 1, 0); /* no data to skip */
mant1_cnt = mant2_cnt = mant4_cnt = 0;
qmant1_ptr = qmant2_ptr = qmant4_ptr = NULL;
- for (ch = 0; ch < s->nb_channels; ch++) {
+ for (ch = 0; ch < s->nb_all_channels; ch++) {
int b, c, e, v;
for(i=0;i<s->nb_coefs[ch];i++) {
}
/* second pass : output the values */
- for (ch = 0; ch < s->nb_channels; ch++) {
+ for (ch = 0; ch < s->nb_all_channels; ch++) {
int b, q;
-
+
for(i=0;i<s->nb_coefs[ch];i++) {
q = qmant[ch][i];
b = bap[ch][i];
case 0:
break;
case 1:
- if (q != 128)
+ if (q != 128)
put_bits(&s->pb, 5, q);
break;
case 2:
- if (q != 128)
+ if (q != 128)
put_bits(&s->pb, 7, q);
break;
case 3:
}
}
-/* compute the ac3 crc */
-
#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
-static void ac3_crc_init(void)
-{
- unsigned int c, n, k;
-
- for(n=0;n<256;n++) {
- c = n << 8;
- for (k = 0; k < 8; k++) {
- if (c & (1 << 15))
- c = ((c << 1) & 0xffff) ^ (CRC16_POLY & 0xffff);
- else
- c = c << 1;
- }
- crc_table[n] = c;
- }
-}
-
-static unsigned int ac3_crc(UINT8 *data, int n, unsigned int crc)
-{
- int i;
- for(i=0;i<n;i++) {
- crc = (crc_table[data[i] ^ (crc >> 8)] ^ (crc << 8)) & 0xffff;
- }
- return crc;
-}
-
static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
{
unsigned int c;
/* compute log2(max(abs(tab[]))) */
-static int log2_tab(INT16 *tab, int n)
+static int log2_tab(int16_t *tab, int n)
{
int i, v;
return av_log2(v);
}
-static void lshift_tab(INT16 *tab, int n, int lshift)
+static void lshift_tab(int16_t *tab, int n, int lshift)
{
int i;
static int output_frame_end(AC3EncodeContext *s)
{
int frame_size, frame_size_58, n, crc1, crc2, crc_inv;
- UINT8 *frame;
+ uint8_t *frame;
frame_size = s->frame_size; /* frame size in words */
/* align to 8 bits */
flush_put_bits(&s->pb);
/* add zero bytes to reach the frame size */
frame = s->pb.buf;
- n = 2 * s->frame_size - (s->pb.buf_ptr - frame) - 2;
+ n = 2 * s->frame_size - (pbBufPtr(&s->pb) - frame) - 2;
assert(n >= 0);
- memset(s->pb.buf_ptr, 0, n);
-
+ if(n>0)
+ memset(pbBufPtr(&s->pb), 0, n);
+
/* Now we must compute both crcs : this is not so easy for crc1
because it is at the beginning of the data... */
frame_size_58 = (frame_size >> 1) + (frame_size >> 3);
- crc1 = ac3_crc(frame + 4, (2 * frame_size_58) - 4, 0);
+ crc1 = bswap_16(av_crc(av_crc8005, 0, frame + 4, 2 * frame_size_58 - 4));
/* XXX: could precompute crc_inv */
crc_inv = pow_poly((CRC16_POLY >> 1), (16 * frame_size_58) - 16, CRC16_POLY);
crc1 = mul_poly(crc_inv, crc1, CRC16_POLY);
- frame[2] = crc1 >> 8;
- frame[3] = crc1;
-
- crc2 = ac3_crc(frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2, 0);
- frame[2*frame_size - 2] = crc2 >> 8;
- frame[2*frame_size - 1] = crc2;
+ AV_WB16(frame+2,crc1);
+
+ crc2 = bswap_16(av_crc(av_crc8005, 0, frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2));
+ AV_WB16(frame+2*frame_size-2,crc2);
// printf("n=%d frame_size=%d\n", n, frame_size);
return frame_size * 2;
}
-int AC3_encode_frame(AVCodecContext *avctx,
- unsigned char *frame, int buf_size, void *data)
+static int AC3_encode_frame(AVCodecContext *avctx,
+ unsigned char *frame, int buf_size, void *data)
{
AC3EncodeContext *s = avctx->priv_data;
- short *samples = data;
+ int16_t *samples = data;
int i, j, k, v, ch;
- INT16 input_samples[N];
- INT32 mdct_coef[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
- UINT8 exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
- UINT8 exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS];
- UINT8 encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
- UINT8 bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
- INT8 exp_samples[NB_BLOCKS][AC3_MAX_CHANNELS];
+ int16_t input_samples[N];
+ int32_t mdct_coef[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ uint8_t exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ uint8_t exp_strategy[NB_BLOCKS][AC3_MAX_CHANNELS];
+ uint8_t encoded_exp[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ uint8_t bap[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ int8_t exp_samples[NB_BLOCKS][AC3_MAX_CHANNELS];
int frame_bits;
frame_bits = 0;
- for(ch=0;ch<s->nb_channels;ch++) {
+ for(ch=0;ch<s->nb_all_channels;ch++) {
/* fixed mdct to the six sub blocks & exponent computation */
for(i=0;i<NB_BLOCKS;i++) {
- INT16 *sptr;
+ int16_t *sptr;
int sinc;
/* compute input samples */
- memcpy(input_samples, s->last_samples[ch], N/2 * sizeof(INT16));
- sinc = s->nb_channels;
+ memcpy(input_samples, s->last_samples[ch], N/2 * sizeof(int16_t));
+ sinc = s->nb_all_channels;
sptr = samples + (sinc * (N/2) * i) + ch;
for(j=0;j<N/2;j++) {
v = *sptr;
input_samples[j + N/2] = v;
- s->last_samples[ch][j] = v;
+ s->last_samples[ch][j] = v;
sptr += sinc;
}
/* apply the MDCT window */
for(j=0;j<N/2;j++) {
- input_samples[j] = MUL16(input_samples[j],
- ac3_window[j]) >> 15;
- input_samples[N-j-1] = MUL16(input_samples[N-j-1],
- ac3_window[j]) >> 15;
+ input_samples[j] = MUL16(input_samples[j],
+ ff_ac3_window[j]) >> 15;
+ input_samples[N-j-1] = MUL16(input_samples[N-j-1],
+ ff_ac3_window[j]) >> 15;
}
-
+
/* Normalize the samples to use the maximum available
precision */
v = 14 - log2_tab(input_samples, N);
if (v < 0)
v = 0;
- exp_samples[i][ch] = v - 8;
+ exp_samples[i][ch] = v - 9;
lshift_tab(input_samples, N, v);
/* do the MDCT */
mdct512(mdct_coef[i][ch], input_samples);
-
+
/* compute "exponents". We take into account the
normalization there */
for(j=0;j<N/2;j++) {
exp[i][ch][j] = e;
}
}
-
- compute_exp_strategy(exp_strategy, exp, ch);
+
+ compute_exp_strategy(exp_strategy, exp, ch, ch == s->lfe_channel);
/* compute the exponents as the decoder will see them. The
EXP_REUSE case must be handled carefully : we select the
j++;
}
frame_bits += encode_exp(encoded_exp[i][ch],
- exp[i][ch], s->nb_coefs[ch],
+ exp[i][ch], s->nb_coefs[ch],
exp_strategy[i][ch]);
/* copy encoded exponents for reuse case */
for(k=i+1;k<j;k++) {
- memcpy(encoded_exp[k][ch], encoded_exp[i][ch],
- s->nb_coefs[ch] * sizeof(UINT8));
+ memcpy(encoded_exp[k][ch], encoded_exp[i][ch],
+ s->nb_coefs[ch] * sizeof(uint8_t));
}
i = j;
}
}
+ /* adjust for fractional frame sizes */
+ while(s->bits_written >= s->bit_rate*1000 && s->samples_written >= s->sample_rate) {
+ s->bits_written -= s->bit_rate*1000;
+ s->samples_written -= s->sample_rate;
+ }
+ s->frame_size = s->frame_size_min + (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate*1000);
+ s->bits_written += s->frame_size * 16;
+ s->samples_written += AC3_FRAME_SIZE;
+
compute_bit_allocation(s, bap, encoded_exp, exp_strategy, frame_bits);
/* everything is known... let's output the frame */
output_frame_header(s, frame);
-
+
for(i=0;i<NB_BLOCKS;i++) {
- output_audio_block(s, exp_strategy[i], encoded_exp[i],
+ output_audio_block(s, exp_strategy[i], encoded_exp[i],
bap[i], mdct_coef[i], exp_samples[i], i);
}
return output_frame_end(s);
}
+static int AC3_encode_close(AVCodecContext *avctx)
+{
+ av_freep(&avctx->coded_frame);
+ return 0;
+}
+
#if 0
/*************************************************************************/
/* TEST */
sum_re += in1[n].re * cos(a) - in1[n].im * sin(a);
sum_im += in1[n].re * sin(a) + in1[n].im * cos(a);
}
- printf("%3d: %6d,%6d %6.0f,%6.0f\n",
- k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
+ printf("%3d: %6d,%6d %6.0f,%6.0f\n",
+ k, in[k].re, in[k].im, sum_re / FN, sum_im / FN);
}
}
void mdct_test(void)
{
- INT16 input[N];
- INT32 output[N/2];
+ int16_t input[N];
+ int32_t output[N/2];
float input1[N];
float output1[N/2];
float s, a, err, e, emax;
}
mdct512(output, input);
-
+
/* do it by hand */
for(k=0;k<N/2;k++) {
s = 0;
}
output1[k] = -2 * s / N;
}
-
+
err = 0;
emax = 0;
for(i=0;i<N/2;i++) {
unsigned char frame[AC3_MAX_CODED_FRAME_SIZE];
short samples[AC3_FRAME_SIZE];
int ret, i;
-
+
AC3_encode_init(&ctx, 44100, 64000, 1);
fft_test();
sizeof(AC3EncodeContext),
AC3_encode_init,
AC3_encode_frame,
+ AC3_encode_close,
NULL,
};
projects / ffmpeg / blobdiff