[Ffmpeg-cvslog] r8302 - trunk/libavcodec/ac3enc.c
jbr
subversion
Fri Mar 9 04:17:44 CET 2007
Author: jbr
Date: Fri Mar 9 04:17:43 2007
New Revision: 8302
Modified:
trunk/libavcodec/ac3enc.c
Log:
simplify AC-3 bit allocation
Modified: trunk/libavcodec/ac3enc.c
==============================================================================
--- trunk/libavcodec/ac3enc.c (original)
+++ trunk/libavcodec/ac3enc.c Fri Mar 9 04:17:43 2007
@@ -83,13 +83,12 @@ static inline int16_t fix15(float a)
return v;
}
-static inline int calc_lowcomp1(int a, int b0, int b1)
+static inline int calc_lowcomp1(int a, int b0, int b1, int c)
{
if ((b0 + 256) == b1) {
- a = 384;
+ a = c;
} else if (b0 > b1) {
- a = a - 64;
- if (a < 0) a=0;
+ a = FFMAX(a - 64, 0);
}
return a;
}
@@ -97,24 +96,12 @@ static inline int calc_lowcomp1(int a, i
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;
- }
+ return calc_lowcomp1(a, b0, b1, 384);
} else if (bin < 20) {
- if ((b0 + 256) == b1) {
- a = 320;
- } else if (b0 > b1) {
- a= a - 64;
- if (a < 0) a=0;
- }
+ return calc_lowcomp1(a, b0, b1, 320);
} else {
- a = a - 128;
- if (a < 0) a=0;
+ return FFMAX(a - 128, 0);
}
- return a;
}
/* AC3 bit allocation. The algorithm is the one described in the AC3
@@ -125,7 +112,7 @@ void ac3_parametric_bit_allocation(AC3Bi
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 bin,i,j,k,end1,v,bndstrt,bndend,lowcomp,begin;
int fastleak,slowleak,address,tmp;
int16_t psd[256]; /* scaled exponents */
int16_t bndpsd[50]; /* interpolated exponents */
@@ -143,22 +130,11 @@ void ac3_parametric_bit_allocation(AC3Bi
do {
v=psd[j];
j++;
- end1=bndtab[k+1];
- if (end1 > end) end1=end;
+ end1 = FFMIN(bndtab[k+1], 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];
- }
+ int adr = FFMIN(FFABS(v - psd[j]) >> 1, 255);
+ v = FFMAX(v, psd[j]) + latab[adr];
j++;
}
bndpsd[k]=v;
@@ -171,14 +147,14 @@ void ac3_parametric_bit_allocation(AC3Bi
if (bndstrt == 0) {
lowcomp = 0;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1]);
+ lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1], 384);
excite[0] = bndpsd[0] - fgain - lowcomp;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2]);
+ lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2], 384);
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]);
+ lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1], 384);
fastleak = bndpsd[bin] - fgain;
slowleak = bndpsd[bin] - s->sgain;
excite[bin] = fastleak - lowcomp;
@@ -197,18 +173,9 @@ void ac3_parametric_bit_allocation(AC3Bi
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;
+ fastleak = FFMAX(fastleak - s->fdecay, bndpsd[bin] - fgain);
+ slowleak = FFMAX(slowleak - s->sdecay, bndpsd[bin] - s->sgain);
+ excite[bin] = FFMAX(fastleak - lowcomp, slowleak);
}
begin = 22;
} else {
@@ -220,29 +187,19 @@ void ac3_parametric_bit_allocation(AC3Bi
}
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;
+ fastleak = FFMAX(fastleak - s->fdecay, bndpsd[bin] - fgain);
+ slowleak = FFMAX(slowleak - s->sdecay, bndpsd[bin] - s->sgain);
+ excite[bin] = FFMAX(fastleak, slowleak);
}
/* compute masking curve */
for (bin = bndstrt; bin < bndend; bin++) {
- v1 = excite[bin];
tmp = s->dbknee - bndpsd[bin];
if (tmp > 0) {
- v1 += tmp >> 2;
+ excite[bin] += tmp >> 2;
}
- v=hth[bin >> s->halfratecod][s->fscod];
- if (v1 > v) v=v1;
- mask[bin] = v;
+ mask[bin] = FFMAX(hth[bin >> s->halfratecod][s->fscod], excite[bin]);
}
/* delta bit allocation */
@@ -269,20 +226,10 @@ void ac3_parametric_bit_allocation(AC3Bi
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;
-
+ v = (FFMAX(mask[j] - snroffset - s->floor, 0) & 0x1FE0) + s->floor;
+ end1 = FFMIN(bndtab[j] + bndsz[j], end);
for (k = i; k < end1; k++) {
- address = (psd[i] - v) >> 5;
- if (address < 0) address=0;
- else if (address > 63) address=63;
+ address = av_clip((psd[i] - v) >> 5, 0, 63);
bap[i] = baptab[address];
i++;
}
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