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avcodec/snow: Hardcode table to save space

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The size of ff_qexp is only 32 bytes, but the code to generate it at
runtime takes 47 bytes (GCC 9.3, x64, -O3 in an av_cold function); so
just hardcode it.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-12-02 03:52:40 +01:00 committed by Andreas Rheinhardt
parent 56df06dd83
commit a7f4abbc62
3 changed files with 9 additions and 13 deletions
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10
libavcodec/snow.c
View File

@ -123,15 +123,6 @@ int ff_snow_alloc_blocks(SnowContext *s){
return 0;
}
static av_cold void init_qexp(void){
int i;
double v=128;
for(i=0; i<QROOT; i++){
ff_qexp[i]= lrintf(v);
v *= pow(2, 1.0 / QROOT);
}
}
static void mc_block(Plane *p, uint8_t *dst, const uint8_t *src, int stride, int b_w, int b_h, int dx, int dy){
static const uint8_t weight[64]={
8,7,6,5,4,3,2,1,
@ -433,7 +424,6 @@ static av_cold void snow_static_init(void)
for (int i = 0; i < MAX_REF_FRAMES; i++)
for (int j = 0; j < MAX_REF_FRAMES; j++)
ff_scale_mv_ref[i][j] = 256 * (i + 1) / (j + 1);
init_qexp();
}
av_cold int ff_snow_common_init(AVCodecContext *avctx){

2
libavcodec/snow.h
View File

@ -194,7 +194,7 @@ typedef struct SnowContext{
/* Tables */
extern const uint8_t * const ff_obmc_tab[4];
extern uint8_t ff_qexp[QROOT];
extern const uint8_t ff_qexp[QROOT];
extern int ff_scale_mv_ref[MAX_REF_FRAMES][MAX_REF_FRAMES];
/* C bits used by mmx/sse2/altivec */

10
libavcodec/snowdata.h
View File

@ -124,8 +124,14 @@ const uint8_t * const ff_obmc_tab[4]= {
obmc32, obmc16, obmc8, obmc4
};
/* runtime generated tables */
uint8_t ff_qexp[QROOT];
/* ff_qexp[i] = lrintf(128 * 2^(i / QROOT)) with QROOT = 32 */
const uint8_t ff_qexp[QROOT] = {
128, 131, 134, 137, 140, 143, 146, 149, 152, 156, 159,
162, 166, 170, 173, 177, 181, 185, 189, 193, 197, 202,
206, 211, 215, 220, 225, 230, 235, 240, 245, 251,
};
/* table generated at runtime */
int ff_scale_mv_ref[MAX_REF_FRAMES][MAX_REF_FRAMES];