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optimizing imdct12

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Originally committed as revision 3929 to svn://svn.ffmpeg.org/ffmpeg/trunk
pull/126/head
Michael Niedermayer 20 years ago
parent 6e0d8c06c7
commit 125d624610
1 changed files with 84 additions and 98 deletions
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  1. 182
      libavcodec/mpegaudiodec.c

182
libavcodec/mpegaudiodec.c
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@ -465,7 +465,9 @@ static int decode_init(AVCodecContext * avctx)
for(i=0;i<36;i++) {
for(j=0; j<4; j++){
double d;
if(j==2) continue;
if(j==2 && i%3 != 1)
continue;
d= sin(M_PI * (i + 0.5) / 36.0);
if(j==1){
@ -478,18 +480,16 @@ static int decode_init(AVCodecContext * avctx)
else if(i< 18) d= 1;
}
//merge last stage of imdct into the window coefficients
if (i/9 == 0) d*= 0.5 / cos(M_PI*(2*( i) +19)/72);
else if(i/9 == 1) d*= 0.5 / cos(M_PI*(2*(17 - i) +19)/72);
else if(i/9 == 2) d*= 0.5 / cos(M_PI*(2*( i) +19)/72);
else d*=-0.5 / cos(M_PI*(2*(17 - i) +19)/72);
mdct_win[j][i] = FIXHR((d / (1<<5)));
d*= 0.5 / cos(M_PI*(2*i + 19)/72);
if(j==2)
mdct_win[j][i/3] = FIXHR((d / (1<<5)));
else
mdct_win[j][i ] = FIXHR((d / (1<<5)));
// av_log(NULL, AV_LOG_DEBUG, "%2d %d %f\n", i,j,d / (1<<5));
}
}
for(i=0;i<12;i++)
mdct_win[2][i] = FIXR(sin(M_PI * (i + 0.5) / 12.0));
/* NOTE: we do frequency inversion adter the MDCT by changing
the sign of the right window coefs */
for(j=0;j<4;j++) {
@ -931,59 +931,63 @@ void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
*synth_buf_offset = offset;
}
/* cos(pi*i/24) */
#define C1 FIXR(0.99144486137381041114)
#define C3 FIXR(0.92387953251128675612)
#define C5 FIXR(0.79335334029123516458)
#define C7 FIXR(0.60876142900872063941)
#define C9 FIXR(0.38268343236508977173)
#define C11 FIXR(0.13052619222005159154)
#define C3 FIXHR(0.86602540378443864676/2)
/* 0.5 / cos(pi*(2*i+1)/36) */
static const int icos36[9] = {
FIXR(0.50190991877167369479),
FIXR(0.51763809020504152469), //0
FIXR(0.55168895948124587824),
FIXR(0.61038729438072803416),
FIXR(0.70710678118654752439), //1
FIXR(0.87172339781054900991),
FIXR(1.18310079157624925896),
FIXR(1.93185165257813657349), //2
FIXR(5.73685662283492756461),
};
/* 12 points IMDCT. We compute it "by hand" by factorizing obvious
cases. */
static void imdct12(int *out, int *in)
{
int tmp;
int64_t in1_3, in1_9, in4_3, in4_9;
in1_3 = MUL64(in[1], C3);
in1_9 = MUL64(in[1], C9);
in4_3 = MUL64(in[4], C3);
in4_9 = MUL64(in[4], C9);
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;
in5 += in3;
in3 += in1;
in2= MULH(2*in2, C3);
in3= MULH(2*in3, C3);
t1 = in0 - in4;
t2 = MULL(in1 - in5, icos36[4]);
out[ 7]=
out[10]= t1 + t2;
out[ 1]=
out[ 4]= t1 - t2;
in0 += in4>>1;
in4 = in0 + in2;
in1 += in5>>1;
in5 = MULL(in1 + in3, icos36[1]);
out[ 8]=
out[ 9]= in4 + in5;
out[ 2]=
out[ 3]= in4 - in5;
tmp = FRAC_RND(MUL64(in[0], C7) - in1_3 - MUL64(in[2], C11) +
MUL64(in[3], C1) - in4_9 - MUL64(in[5], C5));
out[0] = tmp;
out[5] = -tmp;
tmp = FRAC_RND(MUL64(in[0] - in[3], C9) - in1_3 +
MUL64(in[2] + in[5], C3) - in4_9);
out[1] = tmp;
out[4] = -tmp;
tmp = FRAC_RND(MUL64(in[0], C11) - in1_9 + MUL64(in[2], C7) -
MUL64(in[3], C5) + in4_3 - MUL64(in[5], C1));
out[2] = tmp;
out[3] = -tmp;
tmp = FRAC_RND(MUL64(-in[0], C5) + in1_9 + MUL64(in[2], C1) +
MUL64(in[3], C11) - in4_3 - MUL64(in[5], C7));
out[6] = tmp;
out[11] = tmp;
tmp = FRAC_RND(MUL64(-in[0] + in[3], C3) - in1_9 +
MUL64(in[2] + in[5], C9) + in4_3);
out[7] = tmp;
out[10] = tmp;
tmp = FRAC_RND(-MUL64(in[0], C1) - in1_3 - MUL64(in[2], C5) -
MUL64(in[3], C7) - in4_9 - MUL64(in[5], C11));
out[8] = tmp;
out[9] = tmp;
in0 -= in2;
in1 = MULL(in1 - in3, icos36[7]);
out[ 0]=
out[ 5]= in0 - in1;
out[ 6]=
out[11]= in0 + in1;
}
#undef C1
#undef C3
#undef C5
#undef C7
#undef C9
#undef C11
/* cos(pi*i/18) */
#define C1 FIXHR(0.98480775301220805936/2)
#define C2 FIXHR(0.93969262078590838405/2)
@ -995,18 +999,6 @@ static void imdct12(int *out, int *in)
#define C8 FIXHR(0.17364817766693034885/2)
/* 0.5 / cos(pi*(2*i+1)/36) */
static const int icos36[9] = {
FIXR(0.50190991877167369479),
FIXR(0.51763809020504152469),
FIXR(0.55168895948124587824),
FIXR(0.61038729438072803416),
FIXR(0.70710678118654752439),
FIXR(0.87172339781054900991),
FIXR(1.18310079157624925896),
FIXR(1.93185165257813657349),
FIXR(5.73685662283492756461),
};
/* using Lee like decomposition followed by hand coded 9 points DCT */
static void imdct36(int *out, int *buf, int *in, int *win)
{
@ -1092,14 +1084,14 @@ static void imdct36(int *out, int *buf, int *in, int *win)
t0 = (s0 + s1) << 5;
t1 = (s0 - s1) << 5;
out[(9 + j)*SBLIMIT] = -MULH(t1, win[9 + j]) + buf[9 + j];
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;
out[(9 + 8 - j)*SBLIMIT] = -MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];
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]);
buf[ + j] = MULH(t0, win[18 + j]);
@ -1110,7 +1102,7 @@ static void imdct36(int *out, int *buf, int *in, int *win)
s1 = MULL(tmp[17], icos36[4]);
t0 = (s0 + s1) << 5;
t1 = (s0 - s1) << 5;
out[(9 + 4)*SBLIMIT] = -MULH(t1, win[9 + 4]) + buf[9 + 4];
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]);
buf[8 - 4] = MULH(t0, win[18 + 8 - 4]);
@ -1991,11 +1983,9 @@ static void compute_imdct(MPADecodeContext *s,
int32_t *sb_samples,
int32_t *mdct_buf)
{
int32_t *ptr, *win, *win1, *buf, *buf2, *out_ptr, *ptr1;
int32_t in[6];
int32_t out[36];
int32_t *ptr, *win, *win1, *buf, *out_ptr, *ptr1;
int32_t out2[12];
int i, j, k, mdct_long_end, v, sblimit;
int i, j, mdct_long_end, v, sblimit;
/* find last non zero block */
ptr = g->sb_hybrid + 576;
@ -2036,36 +2026,32 @@ static void compute_imdct(MPADecodeContext *s,
buf += 18;
}
for(j=mdct_long_end;j<sblimit;j++) {
for(i=0;i<6;i++) {
out[i] = 0;
out[6 + i] = 0;
out[30+i] = 0;
}
/* select frequency inversion */
win = mdct_win[2] + ((4 * 36) & -(j & 1));
buf2 = out + 6;
for(k=0;k<3;k++) {
/* reorder input for short mdct */
ptr1 = ptr + k;
for(i=0;i<6;i++) {
in[i] = *ptr1;
ptr1 += 3;
}
imdct12(out2, in);
/* apply 12 point window and do small overlap */
for(i=0;i<6;i++) {
buf2[i] = MULL(out2[i], win[i]) + buf2[i];
buf2[i + 6] = MULL(out2[i + 6], win[i + 6]);
}
buf2 += 6;
}
/* overlap */
out_ptr = sb_samples + j;
for(i=0;i<18;i++) {
*out_ptr = out[i] + buf[i];
buf[i] = out[i + 18];
for(i=0; i<6; i++){
*out_ptr = buf[i];
out_ptr += SBLIMIT;
}
imdct12(out2, ptr + 0);
for(i=0;i<6;i++) {
*out_ptr = MULH(out2[i], win[i]) + buf[i + 6*1];
buf[i + 6*2] = MULH(out2[i + 6], win[i + 6]);
out_ptr += SBLIMIT;
}
imdct12(out2, ptr + 1);
for(i=0;i<6;i++) {
*out_ptr = MULH(out2[i], win[i]) + buf[i + 6*2];
buf[i + 6*0] = MULH(out2[i + 6], win[i + 6]);
out_ptr += SBLIMIT;
}
imdct12(out2, ptr + 2);
for(i=0;i<6;i++) {
buf[i + 6*0] = MULH(out2[i], win[i]) + buf[i + 6*0];
buf[i + 6*1] = MULH(out2[i + 6], win[i + 6]);
buf[i + 6*2] = 0;
}
ptr += 18;
buf += 18;
}

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