diff --git a/common/av_common.c b/common/av_common.c
index 277601d2fc..1a23d766b3 100644
--- a/common/av_common.c
+++ b/common/av_common.c
@@ -143,12 +143,14 @@ AVRational mp_get_codec_timebase(const struct mp_codec_params *c)
 
     // If the timebase is too coarse, raise its precision, or small adjustments
     // to timestamps done between decoder and demuxer could be lost.
+    int64_t den = tb.den;
     if (av_q2d(tb) > 0.001) {
-        AVRational r = av_div_q(tb, (AVRational){1, 1000});
-        tb.den *= (r.num + r.den - 1) / r.den;
+        int64_t scaling_num = tb.num * INT64_C(1000);
+        int64_t scaling_den = tb.den;
+        den *= (scaling_num + scaling_den - 1) / scaling_den;
     }
 
-    av_reduce(&tb.num, &tb.den, tb.num, tb.den, INT_MAX);
+    av_reduce(&tb.num, &tb.den, tb.num, den, INT_MAX);
 
     if (tb.num < 1 || tb.den < 1)
         tb = AV_TIME_BASE_Q;