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ffmpeg
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simplify 

Originally committed as revision 3314 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-07-14 18:23:49 +00:00
parent 80d1c272be
commit 5f63d108eb
1 changed files with 25 additions and 38 deletions
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63
libavcodec/utils.c
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@ -786,49 +786,36 @@ char av_get_pict_type_char(int pict_type){
}
int av_reduce(int *dst_nom, int *dst_den, int64_t nom, int64_t den, int64_t max){
int exact=1, sign=0;
int64_t gcd;
AVRational a0={0,1}, a1={1,0};
int sign= (nom<0) ^ (den<0);
int64_t gcd= ff_gcd(ABS(nom), ABS(den));
assert(den != 0);
if(den < 0)
return av_reduce(dst_nom, dst_den, -nom, -den, max);
sign= nom < 0;
nom= ABS(nom);
gcd = ff_gcd(nom, den);
nom /= gcd;
den /= gcd;
if(nom > max || den > max){
AVRational a0={0,1}, a1={1,0};
exact=0;
for(;;){
int64_t x= nom / den;
int64_t a2n= x*a1.num + a0.num;
int64_t a2d= x*a1.den + a0.den;
if(a2n > max || a2d > max) break;
nom %= den;
a0= a1;
a1= (AVRational){a2n, a2d};
if(nom==0) break;
x= nom; nom=den; den=x;
}
nom= a1.num;
den= a1.den;
nom = ABS(nom)/gcd;
den = ABS(den)/gcd;
if(nom<=max && den<=max){
a1= (AVRational){nom, den};
den=0;
}
assert(ff_gcd(nom, den) == 1);
while(den){
int64_t x = nom / den;
int64_t next_den= nom - den*x;
int64_t a2n= x*a1.num + a0.num;
int64_t a2d= x*a1.den + a0.den;
if(a2n > max || a2d > max) break;
a0= a1;
a1= (AVRational){a2n, a2d};
nom= den;
den= next_den;
}
assert(ff_gcd(a1.num, a1.den) == 1);
*dst_nom = sign ? -nom : nom;
*dst_den = den;
*dst_nom = sign ? -a1.num : a1.num;
*dst_den = a1.den;
return exact;
return den==0;
}
int64_t av_rescale(int64_t a, int64_t b, int64_t c){