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-rw-r--r--contrib/ffmpeg/libavcodec/ac3enc.c1557
1 files changed, 1557 insertions, 0 deletions
diff --git a/contrib/ffmpeg/libavcodec/ac3enc.c b/contrib/ffmpeg/libavcodec/ac3enc.c
new file mode 100644
index 000000000..c8c8920ed
--- /dev/null
+++ b/contrib/ffmpeg/libavcodec/ac3enc.c
@@ -0,0 +1,1557 @@
+/*
+ * The simplest AC3 encoder
+ * Copyright (c) 2000 Fabrice Bellard.
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file ac3enc.c
+ * The simplest AC3 encoder.
+ */
+//#define DEBUG
+//#define DEBUG_BITALLOC
+#include "avcodec.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;
+
+#include "ac3tab.h"
+
+#define MDCT_NBITS 9
+#define N (1 << MDCT_NBITS)
+
+/* new exponents are sent if their Norm 1 exceed this number */
+#define EXP_DIFF_THRESHOLD 1000
+
+static void fft_init(int ln);
+
+static inline int16_t fix15(float a)
+{
+ int v;
+ v = (int)(a * (float)(1 << 15));
+ if (v < -32767)
+ 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. */
+void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
+ int8_t *exp, int start, int end,
+ int snroffset, int fgain, int is_lfe,
+ int deltbae,int deltnseg,
+ uint8_t *deltoffst, uint8_t *deltlen, uint8_t *deltba)
+{
+ int bin,i,j,k,end1,v,v1,bndstrt,bndend,lowcomp,begin;
+ int fastleak,slowleak,address,tmp;
+ int16_t psd[256]; /* scaled exponents */
+ int16_t bndpsd[50]; /* interpolated exponents */
+ int16_t excite[50]; /* excitation */
+ int16_t 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;
+
+ if (bndstrt == 0) {
+ 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++) {
+ if (!(is_lfe && bin == 6))
+ lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1]) ;
+ fastleak = bndpsd[bin] - fgain ;
+ slowleak = bndpsd[bin] - s->sgain ;
+ excite[bin] = fastleak - lowcomp ;
+ if (!(is_lfe && bin == 6)) {
+ if (bndpsd[bin] <= bndpsd[bin+1]) {
+ begin = bin + 1 ;
+ break ;
+ }
+ }
+ }
+
+ end1=bndend;
+ if (end1 > 22) end1=22;
+
+ for (bin = begin; bin < end1; bin++) {
+ if (!(is_lfe && bin == 6))
+ 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;
+ }
+ begin = 22;
+ } else {
+ /* coupling channel */
+ begin = bndstrt;
+
+ fastleak = (s->cplfleak << 8) + 768;
+ slowleak = (s->cplsleak << 8) + 768;
+ }
+
+ for (bin = begin; 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;
+ }
+
+ /* delta bit allocation */
+
+ if (deltbae == 0 || deltbae == 1) {
+ int band, seg, delta;
+ band = 0 ;
+ for (seg = 0; seg < deltnseg; seg++) {
+ band += deltoffst[seg] ;
+ if (deltba[seg] >= 4) {
+ delta = (deltba[seg] - 3) << 7;
+ } else {
+ delta = (deltba[seg] - 4) << 7;
+ }
+ for (k = 0; k < deltlen[seg]; k++) {
+ mask[band] += delta ;
+ band++ ;
+ }
+ }
+ }
+
+ /* 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;
+
+static void fft_init(int ln)
+{
+ int i, j, m, n;
+ float alpha;
+
+ n = 1 << ln;
+
+ for(i=0;i<(n/2);i++) {
+ alpha = 2 * M_PI * (float)i / (float)n;
+ costab[i] = fix15(cos(alpha));
+ sintab[i] = fix15(sin(alpha));
+ }
+
+ for(i=0;i<n;i++) {
+ m=0;
+ for(j=0;j<ln;j++) {
+ m |= ((i >> j) & 1) << (ln-j-1);
+ }
+ fft_rev[i]=m;
+ }
+}
+
+/* butter fly op */
+#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
+{\
+ int ax, ay, bx, by;\
+ bx=pre1;\
+ by=pim1;\
+ ax=qre1;\
+ ay=qim1;\
+ pre = (bx + ax) >> 1;\
+ pim = (by + ay) >> 1;\
+ qre = (bx - ax) >> 1;\
+ qim = (by - ay) >> 1;\
+}
+
+#define MUL16(a,b) ((a) * (b))
+
+#define CMUL(pre, pim, are, aim, bre, bim) \
+{\
+ pre = (MUL16(are, bre) - MUL16(aim, bim)) >> 15;\
+ pim = (MUL16(are, bim) + MUL16(bre, aim)) >> 15;\
+}
+
+
+/* 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;
+ register IComplex *p,*q;
+ int tmp_re, tmp_im;
+
+ np = 1 << ln;
+
+ /* reverse */
+ for(j=0;j<np;j++) {
+ int k;
+ IComplex tmp;
+ k = fft_rev[j];
+ if (k < j) {
+ tmp = z[k];
+ z[k] = z[j];
+ z[j] = tmp;
+ }
+ }
+
+ /* pass 0 */
+
+ p=&z[0];
+ j=(np >> 1);
+ do {
+ 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);
+
+ /* pass 1 */
+
+ p=&z[0];
+ j=np >> 2;
+ do {
+ 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,
+ p[1].re, p[1].im, p[3].im, -p[3].re);
+ p+=4;
+ } while (--j != 0);
+
+ /* pass 2 .. ln-1 */
+
+ nblocks = np >> 3;
+ nloops = 1 << 2;
+ np2 = np >> 1;
+ do {
+ p = z;
+ q = z + nloops;
+ for (j = 0; j < nblocks; ++j) {
+
+ 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) {
+ CMUL(tmp_re, tmp_im, costab[l], -sintab[l], q->re, q->im);
+ BF(p->re, p->im, q->re, q->im,
+ p->re, p->im, tmp_re, tmp_im);
+ p++;
+ q++;
+ }
+ p += nloops;
+ q += nloops;
+ }
+ nblocks = nblocks >> 1;
+ nloops = nloops << 1;
+ } while (nblocks != 0);
+}
+
+/* do a 512 point mdct */
+static void mdct512(int32_t *out, int16_t *in)
+{
+ int i, re, im, re1, im1;
+ int16_t rot[N];
+ IComplex x[N/4];
+
+ /* shift to simplify computations */
+ for(i=0;i<N/4;i++)
+ 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;
+ im = -((int)rot[N/2+2*i] - (int)rot[N/2-1-2*i]) >> 1;
+ CMUL(x[i].re, x[i].im, re, im, -xcos1[i], xsin1[i]);
+ }
+
+ fft(x, MDCT_NBITS - 2);
+
+ /* post rotation */
+ for(i=0;i<N/4;i++) {
+ re = x[i].re;
+ im = x[i].im;
+ CMUL(re1, im1, re, im, xsin1[i], xcos1[i]);
+ out[2*i] = im1;
+ out[N/2-1-2*i] = re1;
+ }
+}
+
+/* XXX: use another norm ? */
+static int calc_exp_diff(uint8_t *exp1, uint8_t *exp2, int n)
+{
+ int sum, i;
+ sum = 0;
+ for(i=0;i<n;i++) {
+ sum += abs(exp1[i] - exp2[i]);
+ }
+ return sum;
+}
+
+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
+ 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;
+ while (i < NB_BLOCKS) {
+ j = i + 1;
+ while (j < NB_BLOCKS && exp_strategy[j][ch] == EXP_REUSE)
+ j++;
+ switch(j - i) {
+ case 1:
+ exp_strategy[i][ch] = EXP_D45;
+ break;
+ case 2:
+ case 3:
+ exp_strategy[i][ch] = EXP_D25;
+ break;
+ default:
+ exp_strategy[i][ch] = EXP_D15;
+ break;
+ }
+ i = j;
+ }
+}
+
+/* set exp[i] to min(exp[i], exp1[i]) */
+static void exponent_min(uint8_t exp[N/2], uint8_t exp1[N/2], int n)
+{
+ int i;
+
+ for(i=0;i<n;i++) {
+ if (exp1[i] < exp[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_t encoded_exp[N/2],
+ uint8_t exp[N/2],
+ int nb_exps,
+ int exp_strategy)
+{
+ int group_size, nb_groups, i, j, k, exp_min;
+ uint8_t exp1[N/2];
+
+ switch(exp_strategy) {
+ case EXP_D15:
+ group_size = 1;
+ break;
+ case EXP_D25:
+ group_size = 2;
+ break;
+ default:
+ case EXP_D45:
+ group_size = 4;
+ break;
+ }
+ nb_groups = ((nb_exps + (group_size * 3) - 4) / (3 * group_size)) * 3;
+
+ /* for each group, compute the minimum exponent */
+ exp1[0] = exp[0]; /* DC exponent is handled separately */
+ k = 1;
+ for(i=1;i<=nb_groups;i++) {
+ exp_min = exp[k];
+ assert(exp_min >= 0 && exp_min <= 24);
+ for(j=1;j<group_size;j++) {
+ if (exp[k+j] < exp_min)
+ exp_min = exp[k+j];
+ }
+ exp1[i] = exp_min;
+ k += group_size;
+ }
+
+ /* constraint for DC exponent */
+ if (exp1[0] > 15)
+ exp1[0] = 15;
+
+ /* 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;
+ for(i=1;i<=nb_groups;i++) {
+ for(j=0;j<group_size;j++) {
+ encoded_exp[k+j] = exp1[i];
+ }
+ k += group_size;
+ }
+
+#if defined(DEBUG)
+ av_log(NULL, AV_LOG_DEBUG, "exponents: strategy=%d\n", exp_strategy);
+ for(i=0;i<=nb_groups * group_size;i++) {
+ av_log(NULL, AV_LOG_DEBUG, "%d ", encoded_exp[i]);
+ }
+ av_log(NULL, AV_LOG_DEBUG, "\n");
+#endif
+
+ return 4 + (nb_groups / 3) * 7;
+}
+
+/* return the size in bits taken by the mantissa */
+static int compute_mantissa_size(AC3EncodeContext *s, uint8_t *m, int nb_coefs)
+{
+ int bits, mant, i;
+
+ bits = 0;
+ for(i=0;i<nb_coefs;i++) {
+ mant = m[i];
+ switch(mant) {
+ case 0:
+ /* nothing */
+ break;
+ case 1:
+ /* 3 mantissa in 5 bits */
+ 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)
+ bits += 7;
+ if (++s->mant2_cnt == 3)
+ s->mant2_cnt = 0;
+ break;
+ case 3:
+ bits += 3;
+ break;
+ case 4:
+ /* 2 mantissa in 7 bits */
+ if (s->mant4_cnt == 0)
+ bits += 7;
+ if (++s->mant4_cnt == 2)
+ s->mant4_cnt = 0;
+ break;
+ case 14:
+ bits += 14;
+ break;
+ case 15:
+ bits += 16;
+ break;
+ default:
+ bits += mant - 1;
+ break;
+ }
+ }
+ return bits;
+}
+
+
+static int bit_alloc(AC3EncodeContext *s,
+ 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 csnroffst, int fsnroffst)
+{
+ int i, ch;
+
+ /* 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_all_channels;ch++) {
+ ac3_parametric_bit_allocation(&s->bit_alloc,
+ bap[i][ch], (int8_t *)encoded_exp[i][ch],
+ 0, s->nb_coefs[ch],
+ (((csnroffst-15) << 4) +
+ fsnroffst) << 2,
+ fgaintab[s->fgaincod[ch]],
+ ch == s->lfe_channel,
+ 2, 0, NULL, NULL, NULL);
+ 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,
+ 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_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_t bap1[NB_BLOCKS][AC3_MAX_CHANNELS][N/2];
+ static int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
+
+ /* init default parameters */
+ s->sdecaycod = 2;
+ s->fdecaycod = 1;
+ s->sgaincod = 1;
+ s->dbkneecod = 2;
+ s->floorcod = 4;
+ for(ch=0;ch<s->nb_all_channels;ch++)
+ s->fgaincod[ch] = 4;
+
+ /* compute real values */
+ s->bit_alloc.fscod = s->fscod;
+ s->bit_alloc.halfratecod = s->halfratecod;
+ s->bit_alloc.sdecay = sdecaytab[s->sdecaycod] >> s->halfratecod;
+ s->bit_alloc.fdecay = fdecaytab[s->fdecaycod] >> s->halfratecod;
+ s->bit_alloc.sgain = sgaintab[s->sgaincod];
+ s->bit_alloc.dbknee = dbkneetab[s->dbkneecod];
+ s->bit_alloc.floor = floortab[s->floorcod];
+
+ /* header size */
+ frame_bits += 65;
+ // 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; /* blksw * c, dithflag * c, dynrnge, cplstre */
+ if (s->acmod == 2) {
+ 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; /* chbwcod[6], gainrng[2] */
+ }
+ frame_bits++; /* baie */
+ frame_bits++; /* snr */
+ frame_bits += 2; /* delta / skip */
+ }
+ frame_bits++; /* cplinu for block 0 */
+ /* bit alloc info */
+ /* 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;
+
+ /* 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)
+ csnroffst -= SNR_INC1;
+ if (csnroffst < 0) {
+ 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,
+ 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) {
+ csnroffst++;
+ memcpy(bap, bap1, sizeof(bap1));
+ }
+
+ fsnroffst = 0;
+ while ((fsnroffst + SNR_INC1) <= 15 &&
+ bit_alloc(s, bap1, encoded_exp, exp_strategy, 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,
+ csnroffst, fsnroffst + 1) >= 0) {
+ fsnroffst++;
+ memcpy(bap, bap1, sizeof(bap1));
+ }
+
+ s->csnroffst = csnroffst;
+ 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_all_channels;ch++) {
+ printf("Block #%d Ch%d:\n", i, ch);
+ printf("bap=");
+ for(j=0;j<s->nb_coefs[ch];j++) {
+ printf("%d ",bap[i][ch][j]);
+ }
+ printf("\n");
+ }
+ }
+ }
+#endif
+ return 0;
+}
+
+void ac3_common_init(void)
+{
+ int i, j, k, l, v;
+ /* 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] = l;
+}
+
+
+static int AC3_encode_init(AVCodecContext *avctx)
+{
+ int freq = avctx->sample_rate;
+ int bitrate = avctx->bit_rate;
+ int channels = avctx->channels;
+ AC3EncodeContext *s = avctx->priv_data;
+ int i, j, ch;
+ float alpha;
+ 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;
+
+ /* number of channels */
+ if (channels < 1 || channels > 6)
+ return -1;
+ 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 ((ac3_freqs[j] >> i) == freq)
+ goto found;
+ }
+ return -1;
+ found:
+ s->sample_rate = freq;
+ s->halfratecod = i;
+ s->fscod = j;
+ s->bsid = 8 + s->halfratecod;
+ s->bsmod = 0; /* complete main audio service */
+
+ /* bitrate & frame size */
+ bitrate /= 1000;
+ for(i=0;i<19;i++) {
+ if ((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);
+ 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 */
+ /* XXX: should compute the bandwidth according to the frame
+ size, so that we avoid anoying high freq artefacts */
+ 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;
+
+ ac3_common_init();
+
+ /* mdct init */
+ fft_init(MDCT_NBITS - 2);
+ for(i=0;i<N/4;i++) {
+ alpha = 2 * M_PI * (i + 1.0 / 8.0) / (float)N;
+ xcos1[i] = fix15(-cos(alpha));
+ xsin1[i] = fix15(-sin(alpha));
+ }
+
+ 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);
+
+ put_bits(&s->pb, 16, 0x0b77); /* frame header */
+ put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
+ put_bits(&s->pb, 2, s->fscod);
+ put_bits(&s->pb, 6, s->frmsizecod + (s->frame_size - s->frame_size_min));
+ put_bits(&s->pb, 5, s->bsid);
+ put_bits(&s->pb, 3, s->bsmod);
+ put_bits(&s->pb, 3, s->acmod);
+ if ((s->acmod & 0x01) && s->acmod != 0x01)
+ 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 == 0x02)
+ put_bits(&s->pb, 2, 0); /* surround not indicated */
+ 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 */
+ put_bits(&s->pb, 1, 0); /* no audio production info */
+ put_bits(&s->pb, 1, 0); /* no copyright */
+ put_bits(&s->pb, 1, 1); /* original bitstream */
+ put_bits(&s->pb, 1, 0); /* no time code 1 */
+ put_bits(&s->pb, 1, 0); /* no time code 2 */
+ put_bits(&s->pb, 1, 0); /* no addtional bit stream info */
+}
+
+/* symetric quantization on 'levels' levels */
+static inline int sym_quant(int c, int e, int levels)
+{
+ int v;
+
+ if (c >= 0) {
+ v = (levels * (c << e)) >> 24;
+ v = (v + 1) >> 1;
+ v = (levels >> 1) + v;
+ } else {
+ v = (levels * ((-c) << e)) >> 24;
+ v = (v + 1) >> 1;
+ v = (levels >> 1) - v;
+ }
+ assert (v >= 0 && v < levels);
+ return v;
+}
+
+/* asymetric quantization on 2^qbits levels */
+static inline int asym_quant(int c, int e, int qbits)
+{
+ int lshift, m, v;
+
+ lshift = e + qbits - 24;
+ if (lshift >= 0)
+ v = c << lshift;
+ else
+ v = c >> (-lshift);
+ /* rounding */
+ v = (v + 1) >> 1;
+ m = (1 << (qbits-1));
+ if (v >= m)
+ v = m - 1;
+ assert(v >= -m);
+ return v & ((1 << qbits)-1);
+}
+
+/* Output one audio block. There are NB_BLOCKS audio blocks in one AC3
+ frame */
+static void output_audio_block(AC3EncodeContext *s,
+ 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, rbnd;
+ uint8_t *p;
+ uint16_t qmant[AC3_MAX_CHANNELS][N/2];
+ int exp0, exp1;
+ int mant1_cnt, mant2_cnt, mant4_cnt;
+ uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr;
+ int delta0, delta1, delta2;
+
+ 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++)
+ put_bits(&s->pb, 1, 1); /* no dither */
+ put_bits(&s->pb, 1, 0); /* no dynamic range */
+ if (block_num == 0) {
+ /* for block 0, even if no coupling, we must say it. This is a
+ waste of bit :-) */
+ put_bits(&s->pb, 1, 1); /* coupling strategy present */
+ put_bits(&s->pb, 1, 0); /* no coupling strategy */
+ } else {
+ put_bits(&s->pb, 1, 0); /* no new coupling strategy */
+ }
+
+ if (s->acmod == 2)
+ {
+ 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)
+ {
+ 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_all_channels; ch++) {
+ switch(exp_strategy[ch]) {
+ case EXP_REUSE:
+ continue;
+ case EXP_D15:
+ group_size = 1;
+ break;
+ case EXP_D25:
+ group_size = 2;
+ break;
+ default:
+ case EXP_D45:
+ group_size = 4;
+ break;
+ }
+ nb_groups = (s->nb_coefs[ch] + (group_size * 3) - 4) / (3 * group_size);
+ p = encoded_exp[ch];
+
+ /* first exponent */
+ exp1 = *p++;
+ put_bits(&s->pb, 4, exp1);
+
+ /* next ones are delta encoded */
+ for(i=0;i<nb_groups;i++) {
+ /* merge three delta in one code */
+ exp0 = exp1;
+ exp1 = p[0];
+ p += group_size;
+ delta0 = exp1 - exp0 + 2;
+
+ exp0 = exp1;
+ exp1 = p[0];
+ p += group_size;
+ delta1 = exp1 - exp0 + 2;
+
+ exp0 = exp1;
+ exp1 = p[0];
+ p += group_size;
+ delta2 = exp1 - exp0 + 2;
+
+ put_bits(&s->pb, 7, ((delta0 * 5 + delta1) * 5) + delta2);
+ }
+
+ if (ch != s->lfe_channel)
+ put_bits(&s->pb, 2, 0); /* no gain range info */
+ }
+
+ /* bit allocation info */
+ baie = (block_num == 0);
+ put_bits(&s->pb, 1, baie);
+ if (baie) {
+ put_bits(&s->pb, 2, s->sdecaycod);
+ put_bits(&s->pb, 2, s->fdecaycod);
+ put_bits(&s->pb, 2, s->sgaincod);
+ put_bits(&s->pb, 2, s->dbkneecod);
+ put_bits(&s->pb, 3, s->floorcod);
+ }
+
+ /* snr offset */
+ 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_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 */
+
+ /* mantissa encoding : we use two passes to handle the grouping. A
+ one pass method may be faster, but it would necessitate to
+ modify the output stream. */
+
+ /* first pass: quantize */
+ mant1_cnt = mant2_cnt = mant4_cnt = 0;
+ qmant1_ptr = qmant2_ptr = qmant4_ptr = NULL;
+
+ for (ch = 0; ch < s->nb_all_channels; ch++) {
+ int b, c, e, v;
+
+ for(i=0;i<s->nb_coefs[ch];i++) {
+ c = mdct_coefs[ch][i];
+ e = encoded_exp[ch][i] - global_exp[ch];
+ b = bap[ch][i];
+ switch(b) {
+ case 0:
+ v = 0;
+ break;
+ case 1:
+ v = sym_quant(c, e, 3);
+ switch(mant1_cnt) {
+ case 0:
+ qmant1_ptr = &qmant[ch][i];
+ v = 9 * v;
+ mant1_cnt = 1;
+ break;
+ case 1:
+ *qmant1_ptr += 3 * v;
+ mant1_cnt = 2;
+ v = 128;
+ break;
+ default:
+ *qmant1_ptr += v;
+ mant1_cnt = 0;
+ v = 128;
+ break;
+ }
+ break;
+ case 2:
+ v = sym_quant(c, e, 5);
+ switch(mant2_cnt) {
+ case 0:
+ qmant2_ptr = &qmant[ch][i];
+ v = 25 * v;
+ mant2_cnt = 1;
+ break;
+ case 1:
+ *qmant2_ptr += 5 * v;
+ mant2_cnt = 2;
+ v = 128;
+ break;
+ default:
+ *qmant2_ptr += v;
+ mant2_cnt = 0;
+ v = 128;
+ break;
+ }
+ break;
+ case 3:
+ v = sym_quant(c, e, 7);
+ break;
+ case 4:
+ v = sym_quant(c, e, 11);
+ switch(mant4_cnt) {
+ case 0:
+ qmant4_ptr = &qmant[ch][i];
+ v = 11 * v;
+ mant4_cnt = 1;
+ break;
+ default:
+ *qmant4_ptr += v;
+ mant4_cnt = 0;
+ v = 128;
+ break;
+ }
+ break;
+ case 5:
+ v = sym_quant(c, e, 15);
+ break;
+ case 14:
+ v = asym_quant(c, e, 14);
+ break;
+ case 15:
+ v = asym_quant(c, e, 16);
+ break;
+ default:
+ v = asym_quant(c, e, b - 1);
+ break;
+ }
+ qmant[ch][i] = v;
+ }
+ }
+
+ /* second pass : output the values */
+ 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];
+ switch(b) {
+ case 0:
+ break;
+ case 1:
+ if (q != 128)
+ put_bits(&s->pb, 5, q);
+ break;
+ case 2:
+ if (q != 128)
+ put_bits(&s->pb, 7, q);
+ break;
+ case 3:
+ put_bits(&s->pb, 3, q);
+ break;
+ case 4:
+ if (q != 128)
+ put_bits(&s->pb, 7, q);
+ break;
+ case 14:
+ put_bits(&s->pb, 14, q);
+ break;
+ case 15:
+ put_bits(&s->pb, 16, q);
+ break;
+ default:
+ put_bits(&s->pb, b - 1, q);
+ break;
+ }
+ }
+ }
+}
+
+#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
+
+static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
+{
+ unsigned int c;
+
+ c = 0;
+ while (a) {
+ if (a & 1)
+ c ^= b;
+ a = a >> 1;
+ b = b << 1;
+ if (b & (1 << 16))
+ b ^= poly;
+ }
+ return c;
+}
+
+static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
+{
+ unsigned int r;
+ r = 1;
+ while (n) {
+ if (n & 1)
+ r = mul_poly(r, a, poly);
+ a = mul_poly(a, a, poly);
+ n >>= 1;
+ }
+ return r;
+}
+
+
+/* compute log2(max(abs(tab[]))) */
+static int log2_tab(int16_t *tab, int n)
+{
+ int i, v;
+
+ v = 0;
+ for(i=0;i<n;i++) {
+ v |= abs(tab[i]);
+ }
+ return av_log2(v);
+}
+
+static void lshift_tab(int16_t *tab, int n, int lshift)
+{
+ int i;
+
+ if (lshift > 0) {
+ for(i=0;i<n;i++) {
+ tab[i] <<= lshift;
+ }
+ } else if (lshift < 0) {
+ lshift = -lshift;
+ for(i=0;i<n;i++) {
+ tab[i] >>= lshift;
+ }
+ }
+}
+
+/* fill the end of the frame and compute the two crcs */
+static int output_frame_end(AC3EncodeContext *s)
+{
+ int frame_size, frame_size_58, n, crc1, crc2, crc_inv;
+ 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 - (pbBufPtr(&s->pb) - frame) - 2;
+ assert(n >= 0);
+ 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 = 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 = bswap_16(av_crc(av_crc8005, 0, frame + 2 * frame_size_58, (frame_size - frame_size_58) * 2 - 2));
+ frame[2*frame_size - 2] = crc2 >> 8;
+ frame[2*frame_size - 1] = crc2;
+
+ // printf("n=%d frame_size=%d\n", n, frame_size);
+ return frame_size * 2;
+}
+
+static int AC3_encode_frame(AVCodecContext *avctx,
+ unsigned char *frame, int buf_size, void *data)
+{
+ AC3EncodeContext *s = avctx->priv_data;
+ int16_t *samples = data;
+ int i, j, k, v, ch;
+ 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_all_channels;ch++) {
+ /* fixed mdct to the six sub blocks & exponent computation */
+ for(i=0;i<NB_BLOCKS;i++) {
+ int16_t *sptr;
+ int sinc;
+
+ /* compute input samples */
+ 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;
+ 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;
+ }
+
+ /* 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 - 10;
+ 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++) {
+ int e;
+ v = abs(mdct_coef[i][ch][j]);
+ if (v == 0)
+ e = 24;
+ else {
+ e = 23 - av_log2(v) + exp_samples[i][ch];
+ if (e >= 24) {
+ e = 24;
+ mdct_coef[i][ch][j] = 0;
+ }
+ }
+ exp[i][ch][j] = e;
+ }
+ }
+
+ 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
+ min of the exponents */
+ i = 0;
+ while (i < NB_BLOCKS) {
+ j = i + 1;
+ while (j < NB_BLOCKS && exp_strategy[j][ch] == EXP_REUSE) {
+ exponent_min(exp[i][ch], exp[j][ch], s->nb_coefs[ch]);
+ j++;
+ }
+ frame_bits += encode_exp(encoded_exp[i][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_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],
+ 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 */
+
+#define FN (N/4)
+
+void fft_test(void)
+{
+ IComplex in[FN], in1[FN];
+ int k, n, i;
+ float sum_re, sum_im, a;
+
+ /* FFT test */
+
+ for(i=0;i<FN;i++) {
+ in[i].re = random() % 65535 - 32767;
+ in[i].im = random() % 65535 - 32767;
+ in1[i] = in[i];
+ }
+ fft(in, 7);
+
+ /* do it by hand */
+ for(k=0;k<FN;k++) {
+ sum_re = 0;
+ sum_im = 0;
+ for(n=0;n<FN;n++) {
+ a = -2 * M_PI * (n * k) / FN;
+ 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);
+ }
+}
+
+void mdct_test(void)
+{
+ int16_t input[N];
+ int32_t output[N/2];
+ float input1[N];
+ float output1[N/2];
+ float s, a, err, e, emax;
+ int i, k, n;
+
+ for(i=0;i<N;i++) {
+ input[i] = (random() % 65535 - 32767) * 9 / 10;
+ input1[i] = input[i];
+ }
+
+ mdct512(output, input);
+
+ /* do it by hand */
+ for(k=0;k<N/2;k++) {
+ s = 0;
+ for(n=0;n<N;n++) {
+ a = (2*M_PI*(2*n+1+N/2)*(2*k+1) / (4 * N));
+ s += input1[n] * cos(a);
+ }
+ output1[k] = -2 * s / N;
+ }
+
+ err = 0;
+ emax = 0;
+ for(i=0;i<N/2;i++) {
+ printf("%3d: %7d %7.0f\n", i, output[i], output1[i]);
+ e = output[i] - output1[i];
+ if (e > emax)
+ emax = e;
+ err += e * e;
+ }
+ printf("err2=%f emax=%f\n", err / (N/2), emax);
+}
+
+void test_ac3(void)
+{
+ AC3EncodeContext ctx;
+ 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();
+ mdct_test();
+
+ for(i=0;i<AC3_FRAME_SIZE;i++)
+ samples[i] = (int)(sin(2*M_PI*i*1000.0/44100) * 10000);
+ ret = AC3_encode_frame(&ctx, frame, samples);
+ printf("ret=%d\n", ret);
+}
+#endif
+
+AVCodec ac3_encoder = {
+ "ac3",
+ CODEC_TYPE_AUDIO,
+ CODEC_ID_AC3,
+ sizeof(AC3EncodeContext),
+ AC3_encode_init,
+ AC3_encode_frame,
+ AC3_encode_close,
+ NULL,
+};
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