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simplify lpc

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Originally committed as revision 10628 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Loren Merritt 2007-09-30 03:36:13 +00:00
parent d1a5c4216c
commit b8de342919
1 changed files with 14 additions and 15 deletions
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29
libavcodec/flacenc.c
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@ -876,10 +876,10 @@ static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
} }
#define LPC1(x) {\ #define LPC1(x) {\
int s = smp[i-(x)+1];\ int c = coefs[(x)-1];\
p1 += c*s;\
c = coefs[(x)-2];\
p0 += c*s;\ p0 += c*s;\
s = smp[i-(x)+1];\
p1 += c*s;\
} }
static av_always_inline void encode_residual_lpc_unrolled( static av_always_inline void encode_residual_lpc_unrolled(
@ -888,9 +888,8 @@ static av_always_inline void encode_residual_lpc_unrolled(
{ {
int i; int i;
for(i=order; i<n; i+=2) { for(i=order; i<n; i+=2) {
int c = coefs[order-1]; int s = smp[i-order];
int p0 = c * smp[i-order]; int p0 = 0, p1 = 0;
int p1 = 0;
if(big) { if(big) {
switch(order) { switch(order) {
case 32: LPC1(32) case 32: LPC1(32)
@ -924,6 +923,7 @@ static av_always_inline void encode_residual_lpc_unrolled(
LPC1( 4) LPC1( 4)
LPC1( 3) LPC1( 3)
LPC1( 2) LPC1( 2)
LPC1( 1)
} }
} else { } else {
switch(order) { switch(order) {
@ -934,9 +934,9 @@ static av_always_inline void encode_residual_lpc_unrolled(
case 4: LPC1( 4) case 4: LPC1( 4)
case 3: LPC1( 3) case 3: LPC1( 3)
case 2: LPC1( 2) case 2: LPC1( 2)
case 1: LPC1( 1)
} }
} }
p1 += c * smp[i];
res[i ] = smp[i ] - (p0 >> shift); res[i ] = smp[i ] - (p0 >> shift);
res[i+1] = smp[i+1] - (p1 >> shift); res[i+1] = smp[i+1] - (p1 >> shift);
} }
@ -952,16 +952,15 @@ static void encode_residual_lpc(int32_t *res, const int32_t *smp, int n,
#ifdef CONFIG_SMALL #ifdef CONFIG_SMALL
for(i=order; i<n; i+=2) { for(i=order; i<n; i+=2) {
int j; int j;
int32_t c = coefs[0]; int s = smp[i];
int32_t p0 = 0, p1 = c*smp[i]; int p0 = 0, p1 = 0;
for(j=1; j<order; j++) { for(j=0; j<order; j++) {
int32_t s = smp[i-j]; int c = coefs[j];
p0 += c*s;
c = coefs[j];
p1 += c*s; p1 += c*s;
s = smp[i-j-1];
p0 += c*s;
} }
p0 += c*smp[i-order]; res[i ] = smp[i ] - (p0 >> shift);
res[i+0] = smp[i+0] - (p0 >> shift);
res[i+1] = smp[i+1] - (p1 >> shift); res[i+1] = smp[i+1] - (p1 >> shift);
} }
#else #else