diff --git a/common/common.c b/common/common.c
index e59db7e906..9f8230fbff 100644
--- a/common/common.c
+++ b/common/common.c
@@ -21,6 +21,7 @@
 
 #include <libavutil/common.h>
 #include <libavutil/error.h>
+#include <libavutil/mathematics.h>
 
 #include "mpv_talloc.h"
 #include "misc/bstr.h"
@@ -404,3 +405,9 @@ uint32_t mp_round_next_power_of_2(uint32_t v)
     int l = mp_log2(v) + 1;
     return l == 32 ? 0 : (uint32_t)1 << l;
 }
+
+int mp_lcm(int x, int y)
+{
+    assert(x && y);
+    return x * (y / av_gcd(x, y));
+}
diff --git a/common/common.h b/common/common.h
index a30a5d6e0c..4015f9b8c3 100644
--- a/common/common.h
+++ b/common/common.h
@@ -113,6 +113,7 @@ void mp_rect_rotate(struct mp_rect *rc, int w, int h, int rotation);
 
 unsigned int mp_log2(uint32_t v);
 uint32_t mp_round_next_power_of_2(uint32_t v);
+int mp_lcm(int x, int y);
 
 int mp_snprintf_cat(char *str, size_t size, const char *format, ...)
     PRINTF_ATTRIBUTE(3, 4);