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av_rescale with user specified rounding

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Originally committed as revision 3481 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer
2004-09-19 16:38:54 +00:00
parent aa25a462b6
commit 1f0182250a
2 changed files with 30 additions and 9 deletions
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24
libavcodec/utils.c
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@@ -822,25 +822,33 @@ int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max)
return den==0;
}
int64_t av_rescale(int64_t a, int64_t b, int64_t c){
AVInteger ai, ci;
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd){
AVInteger ai;
int64_t r=0;
assert(c > 0);
assert(b >=0);
assert(rnd >=0 && rnd<=5 && rnd!=4);
if(a<0) return -av_rescale(-a, b, c);
if(a<0) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
if(rnd==AV_ROUND_NEAR_INF) r= c/2;
else if(rnd&1) r= c-1;
if(b<=INT_MAX && c<=INT_MAX){
if(a<=INT_MAX)
return (a * b + c/2)/c;
return (a * b + r)/c;
else
return a/c*b + (a%c*b + c/2)/c;
return a/c*b + (a%c*b + r)/c;
}
ai= av_mul_i(av_int2i(a), av_int2i(b));
ci= av_int2i(c);
ai= av_add_i(ai, av_shr_i(ci,1));
ai= av_add_i(ai, av_int2i(r));
return av_i2int(av_div_i(ai, ci));
return av_i2int(av_div_i(ai, av_int2i(c)));
}
int64_t av_rescale(int64_t a, int64_t b, int64_t c){
return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
}
/* av_log API */