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AAC: Unswitch loop over window groups in decode_spectrum_and_dequant()

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GCC should be able to do this, but doesn't.  Slightly faster code.

Originally committed as revision 21190 to svn://svn.ffmpeg.org/ffmpeg/trunk
release/0.6
Måns Rullgård 15 years ago
parent 05f9d8fcaa
commit 95dff4aced
1 changed files with 39 additions and 15 deletions
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  1. 54
      libavcodec/aac.c

54
libavcodec/aac.c
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@ -982,13 +982,12 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
VLC_TYPE (*vlc_tab)[2] = vlc_spectral[cbt_m1].table;
const int cb_size = ff_aac_spectral_sizes[cbt_m1];
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
uint32_t *icf = (uint32_t *) cf;
int len = off_len;
switch (cbt_m1 >> 1) {
case 0:
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
int len = off_len;
switch (cbt_m1 >> 1) {
case 0:
do {
const int index = get_vlc2(gb, vlc_tab, 6, 3);
unsigned cb_idx;
@ -1001,8 +1000,14 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
cb_idx = cb_vector_idx[index];
cf = VMUL4(cf, vq, cb_idx, sf + idx);
} while (len -= 4);
break;
case 1:
}
break;
case 1:
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
int len = off_len;
do {
const int index = get_vlc2(gb, vlc_tab, 6, 3);
unsigned nnz;
@ -1019,8 +1024,14 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
bits = get_bits(gb, nnz) << (32-nnz);
cf = VMUL4S(cf, vq, cb_idx, bits, sf + idx);
} while (len -= 4);
break;
case 2:
}
break;
case 2:
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
int len = off_len;
do {
const int index = get_vlc2(gb, vlc_tab, 6, 3);
unsigned cb_idx;
@ -1033,9 +1044,15 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
cb_idx = cb_vector_idx[index];
cf = VMUL2(cf, vq, cb_idx, sf + idx);
} while (len -= 2);
break;
case 3:
case 4:
}
break;
case 3:
case 4:
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
int len = off_len;
do {
const int index = get_vlc2(gb, vlc_tab, 6, 3);
unsigned nnz;
@ -1052,8 +1069,15 @@ static int decode_spectrum_and_dequant(AACContext *ac, float coef[1024],
sign = get_bits(gb, nnz) << (cb_idx >> 12);
cf = VMUL2S(cf, vq, cb_idx, sign, sf + idx);
} while (len -= 2);
break;
default:
}
break;
default:
for (group = 0; group < g_len; group++, cfo+=128) {
float *cf = cfo;
uint32_t *icf = (uint32_t *) cf;
int len = off_len;
do {
const int index = get_vlc2(gb, vlc_tab, 6, 3);
unsigned nzt, nnz;

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