[FFmpeg-devel] [PATCH 1/3] avutil/rational: increase av_d2q precision

Marton Balint cus at passwd.hu
Sun Jan 28 05:01:34 EET 2024


Fixes parsing small timebases from expressions (where the expression API
converts the result to double), like in this command line:

ffprobe -f lavfi -i testsrc=d=1,settb=1/2000000000 -show_streams -show_entries stream=time_base

Before the patch timebase was parsed as 1/1999999999.

Signed-off-by: Marton Balint <cus at passwd.hu>
---
 libavutil/rational.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavutil/rational.c b/libavutil/rational.c
index eb148ddb12..329fbf3302 100644
--- a/libavutil/rational.c
+++ b/libavutil/rational.c
@@ -114,7 +114,7 @@ AVRational av_d2q(double d, int max)
         return (AVRational) { d < 0 ? -1 : 1, 0 };
     frexp(d, &exponent);
     exponent = FFMAX(exponent-1, 0);
-    den = 1LL << (61 - exponent);
+    den = 1LL << (62 - exponent);
     // (int64_t)rint() and llrint() do not work with gcc on ia64 and sparc64,
     // see Ticket2713 for affected gcc/glibc versions
     av_reduce(&a.num, &a.den, floor(d * den + 0.5), den, max);
-- 
2.35.3



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