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-rw-r--r--libavcodec/ac3.h56
-rw-r--r--libavcodec/ac3enc.c218
-rw-r--r--libavcodec/ac3enc.h34
-rw-r--r--libavcodec/ac3tab.h19
4 files changed, 206 insertions, 121 deletions
diff --git a/libavcodec/ac3.h b/libavcodec/ac3.h
new file mode 100644
index 0000000000..d62c3c168b
--- /dev/null
+++ b/libavcodec/ac3.h
@@ -0,0 +1,56 @@
+/*
+ * Common code between AC3 encoder and decoder
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
+ *
+ * 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
+ */
+
+#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
+#define AC3_MAX_CHANNELS 6 /* including LFE channel */
+
+#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
+#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
+
+/* exponent encoding strategy */
+#define EXP_REUSE 0
+#define EXP_NEW 1
+
+#define EXP_D15 1
+#define EXP_D25 2
+#define EXP_D45 3
+
+typedef struct AC3BitAllocParameters {
+ int fscod; /* frequency */
+ int halfratecod;
+ int sgain, sdecay, fdecay, dbknee, floor;
+ int cplfleak, cplsleak;
+} AC3BitAllocParameters;
+
+extern const UINT16 ac3_freqs[3];
+extern const UINT16 ac3_bitratetab[19];
+extern const INT16 ac3_window[256];
+extern const UINT8 sdecaytab[4];
+extern const UINT8 fdecaytab[4];
+extern const UINT16 sgaintab[4];
+extern const UINT16 dbkneetab[4];
+extern const UINT16 floortab[8];
+extern const UINT16 fgaintab[8];
+
+void ac3_common_init(void);
+void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
+ INT8 *exp, int start, int end,
+ int snroffset, int fgain, int is_lfe,
+ int deltbae,int deltnseg,
+ UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba);
diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index cce8abfda1..fbd68210ad 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -20,25 +20,46 @@
//#define DEBUG_BITALLOC
#include "avcodec.h"
-#include "ac3enc.h"
-#include "ac3tab.h"
+#include "ac3.h"
+
+typedef struct AC3EncodeContext {
+ PutBitContext pb;
+ int nb_channels;
+ int nb_all_channels;
+ int lfe_channel;
+ int bit_rate;
+ int sample_rate;
+ int bsid;
+ int frame_size_min; /* minimum frame size in case rounding is necessary */
+ int frame_size; /* current frame size in words */
+ int halfratecod;
+ int frmsizecod;
+ int fscod; /* frequency */
+ int acmod;
+ int lfe;
+ int bsmod;
+ short last_samples[AC3_MAX_CHANNELS][256];
+ 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)
-#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);
@@ -88,11 +109,12 @@ static inline int calc_lowcomp(int a, int b0, int b1, int bin)
}
/* 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 is_lfe)
+ spec. */
+void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
+ INT8 *exp, int start, int end,
+ int snroffset, int fgain, int is_lfe,
+ int deltbae,int deltnseg,
+ UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba)
{
int bin,i,j,k,end1,v,v1,bndstrt,bndend,lowcomp,begin;
int fastleak,slowleak,address,tmp;
@@ -138,48 +160,57 @@ void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
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++) {
- 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 ;
- }
- }
- }
+ 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;
+ 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) ;
+ 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;
+ 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;
+ slowleak -= s->sdecay ;
+ v = bndpsd[bin] - s->sgain;
+ if (slowleak < v) slowleak = v;
- v=fastleak - lowcomp;
- if (slowleak > v) v=slowleak;
+ v=fastleak - lowcomp;
+ if (slowleak > v) v=slowleak;
- excite[bin] = v;
+ excite[bin] = v;
+ }
+ begin = 22;
+ } else {
+ /* coupling channel */
+ begin = bndstrt;
+
+ fastleak = (s->cplfleak << 8) + 768;
+ slowleak = (s->cplsleak << 8) + 768;
}
- for (bin = 22; bin < bndend; bin++) {
+ for (bin = begin; bin < bndend; bin++) {
fastleak -= s->fdecay ;
v = bndpsd[bin] - fgain;
if (fastleak < v) fastleak = v;
@@ -205,6 +236,25 @@ void parametric_bit_allocation(AC3EncodeContext *s, UINT8 *bap,
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 ;
@@ -600,12 +650,14 @@ static int bit_alloc(AC3EncodeContext *s,
s->mant2_cnt = 0;
s->mant4_cnt = 0;
for(ch=0;ch<s->nb_all_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]],
- ch == s->lfe_channel);
+ ac3_parametric_bit_allocation(&s->bit_alloc,
+ bap[i][ch], (INT8 *)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]);
}
@@ -641,12 +693,14 @@ static int compute_bit_allocation(AC3EncodeContext *s,
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 = 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)
@@ -738,16 +792,31 @@ static int compute_bit_allocation(AC3EncodeContext *s,
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] = 0;
+}
+
+
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, k, l, ch, v;
+ int i, j, ch;
float alpha;
- static unsigned short freqs[3] = { 48000, 44100, 32000 };
- static int acmod_defs[6] = {
+ static const UINT8 acmod_defs[6] = {
0x01, /* C */
0x02, /* L R */
0x03, /* L C R */
@@ -771,7 +840,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
/* frequency */
for(i=0;i<3;i++) {
for(j=0;j<3;j++)
- if ((freqs[j] >> i) == freq)
+ if ((ac3_freqs[j] >> i) == freq)
goto found;
}
return -1;
@@ -785,7 +854,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
/* bitrate & frame size */
bitrate /= 1000;
for(i=0;i<19;i++) {
- if ((bitratetab[i] >> s->halfratecod) == bitrate)
+ if ((ac3_bitratetab[i] >> s->halfratecod) == bitrate)
break;
}
if (i == 19)
@@ -810,16 +879,7 @@ static int AC3_encode_init(AVCodecContext *avctx)
/* 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;
+ ac3_common_init();
/* mdct init */
fft_init(MDCT_NBITS - 2);
@@ -1282,8 +1342,8 @@ static int output_frame_end(AC3EncodeContext *s)
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;
diff --git a/libavcodec/ac3enc.h b/libavcodec/ac3enc.h
deleted file mode 100644
index 6dd0966ec8..0000000000
--- a/libavcodec/ac3enc.h
+++ /dev/null
@@ -1,34 +0,0 @@
-
-#define AC3_FRAME_SIZE (6*256)
-#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
-#define AC3_MAX_CHANNELS 6
-
-typedef struct AC3EncodeContext {
- PutBitContext pb;
- int nb_channels;
- int nb_all_channels;
- int lfe_channel;
- int bit_rate;
- int sample_rate;
- int bsid;
- int frame_size_min; /* minimum frame size in case rounding is necessary */
- int frame_size; /* current frame size in words */
- int halfratecod;
- int frmsizecod;
- int fscod; /* frequency */
- int acmod;
- int lfe;
- int bsmod;
- short last_samples[AC3_MAX_CHANNELS][256];
- int chbwcod[AC3_MAX_CHANNELS];
- int nb_coefs[AC3_MAX_CHANNELS];
-
- /* bitrate allocation control */
- int sgaincod, sdecaycod, fdecaycod, dbkneecod, floorcod;
- int sgain, sdecay, fdecay, dbknee, floor;
- int csnroffst;
- int fgaincod[AC3_MAX_CHANNELS];
- int fsnroffst[AC3_MAX_CHANNELS];
- /* mantissa encoding */
- int mant1_cnt, mant2_cnt, mant4_cnt;
-} AC3EncodeContext;
diff --git a/libavcodec/ac3tab.h b/libavcodec/ac3tab.h
index 2d379f0404..730266dae8 100644
--- a/libavcodec/ac3tab.h
+++ b/libavcodec/ac3tab.h
@@ -1,7 +1,10 @@
/* tables taken directly from AC3 spec */
+/* possible frequencies */
+const UINT16 ac3_freqs[3] = { 48000, 44100, 32000 };
+
/* possible bitrates */
-static const UINT16 bitratetab[19] = {
+const UINT16 ac3_bitratetab[19] = {
32, 40, 48, 56, 64, 80, 96, 112, 128,
160, 192, 224, 256, 320, 384, 448, 512, 576, 640
};
@@ -9,7 +12,7 @@ static const UINT16 bitratetab[19] = {
/* AC3 MDCT window */
/* MDCT window */
-static const INT16 ac3_window[256]= {
+const INT16 ac3_window[256] = {
4, 7, 12, 16, 21, 28, 34, 42,
51, 61, 72, 84, 97, 111, 127, 145,
164, 184, 207, 231, 257, 285, 315, 347,
@@ -138,27 +141,27 @@ static const UINT8 baptab[64]= {
15, 15, 15, 15,
};
-static const UINT8 sdecaytab[4]={
+const UINT8 sdecaytab[4]={
0x0f, 0x11, 0x13, 0x15,
};
-static const UINT8 fdecaytab[4]={
+const UINT8 fdecaytab[4]={
0x3f, 0x53, 0x67, 0x7b,
};
-static const UINT16 sgaintab[4]= {
+const UINT16 sgaintab[4]= {
0x540, 0x4d8, 0x478, 0x410,
};
-static const UINT16 dbkneetab[4]= {
+const UINT16 dbkneetab[4]= {
0x000, 0x700, 0x900, 0xb00,
};
-static const UINT16 floortab[8]= {
+const UINT16 floortab[8]= {
0x2f0, 0x2b0, 0x270, 0x230, 0x1f0, 0x170, 0x0f0, 0xf800,
};
-static const UINT16 fgaintab[8]= {
+const UINT16 fgaintab[8]= {
0x080, 0x100, 0x180, 0x200, 0x280, 0x300, 0x380, 0x400,
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-08 14:29:08 +0000