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merge a few shifts into the dequantization, faster and more accurate, lets hope it doesnt overflow

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Originally committed as revision 3930 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2005-02-03 03:28:27 +00:00
parent 125d624610
commit 44f1698a38
1 changed files with 18 additions and 17 deletions
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35
libavcodec/mpegaudiodec.c
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@ -405,7 +405,7 @@ static int decode_init(AVCodecContext * avctx)
f = pow((double)(i/4), 4.0 / 3.0) * pow(2, (i&3)*0.25);
fm = frexp(f, &e);
m = FIXHR(fm*0.5);
e+= FRAC_BITS - 31;
e+= FRAC_BITS - 31 + 5;
/* normalized to FRAC_BITS */
table_4_3_value[i] = m;
@ -951,12 +951,13 @@ static const int icos36[9] = {
static void imdct12(int *out, int *in)
{
int in0, in1, in2, in3, in4, in5, t1, t2;
in0= in[0*3]<<5;
in1= (in[1*3] + in[0*3])<<5;
in2= (in[2*3] + in[1*3])<<5;
in3= (in[3*3] + in[2*3])<<5;
in4= (in[4*3] + in[3*3])<<5;
in5= (in[5*3] + in[4*3])<<5;
in0= in[0*3];
in1= in[1*3] + in[0*3];
in2= in[2*3] + in[1*3];
in3= in[3*3] + in[2*3];
in4= in[4*3] + in[3*3];
in5= in[5*3] + in[4*3];
in5 += in3;
in3 += in1;
@ -1082,15 +1083,15 @@ static void imdct36(int *out, int *buf, int *in, int *win)
s1 = MULL(t3 + t2, icos36[j]);
s3 = MULL(t3 - t2, icos36[8 - j]);
t0 = (s0 + s1) << 5;
t1 = (s0 - s1) << 5;
t0 = s0 + s1;
t1 = s0 - s1;
out[(9 + j)*SBLIMIT] = MULH(t1, win[9 + j]) + buf[9 + j];
out[(8 - j)*SBLIMIT] = MULH(t1, win[8 - j]) + buf[8 - j];
buf[9 + j] = MULH(t0, win[18 + 9 + j]);
buf[8 - j] = MULH(t0, win[18 + 8 - j]);
t0 = (s2 + s3) << 5;
t1 = (s2 - s3) << 5;
t0 = s2 + s3;
t1 = s2 - s3;
out[(9 + 8 - j)*SBLIMIT] = MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];
out[( j)*SBLIMIT] = MULH(t1, win[ j]) + buf[ j];
buf[9 + 8 - j] = MULH(t0, win[18 + 9 + 8 - j]);
@ -1100,8 +1101,8 @@ static void imdct36(int *out, int *buf, int *in, int *win)
s0 = tmp[16];
s1 = MULL(tmp[17], icos36[4]);
t0 = (s0 + s1) << 5;
t1 = (s0 - s1) << 5;
t0 = s0 + s1;
t1 = s0 - s1;
out[(9 + 4)*SBLIMIT] = MULH(t1, win[9 + 4]) + buf[9 + 4];
out[(8 - 4)*SBLIMIT] = MULH(t1, win[8 - 4]) + buf[8 - 4];
buf[9 + 4] = MULH(t0, win[18 + 9 + 4]);
@ -1920,11 +1921,11 @@ static void compute_antialias_integer(MPADecodeContext *s,
int tmp0, tmp1, tmp2;
csa = &csa_table[0][0];
#define INT_AA(j) \
tmp0 = 4*(ptr[-1-j]);\
tmp1 = 4*(ptr[ j]);\
tmp0 = ptr[-1-j];\
tmp1 = ptr[ j];\
tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\
ptr[-1-j] = tmp2 - MULH(tmp1, csa[2+4*j]);\
ptr[ j] = tmp2 + MULH(tmp0, csa[3+4*j]);
ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\
ptr[ j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));
INT_AA(0)
INT_AA(1)