diff --git a/drivers/video/video_stm32_dcmi.c b/drivers/video/video_stm32_dcmi.c
index 055d5199ae7ec..73394b6ac0783 100644
--- a/drivers/video/video_stm32_dcmi.c
+++ b/drivers/video/video_stm32_dcmi.c
@@ -375,10 +375,12 @@ static int video_stm32_dcmi_set_frmival(const struct device *dev, struct video_f
 		.format = &data->fmt,
 	};
 	struct video_frmival best_sensor_frmival;
-	uint64_t best_diff_nsec = INT32_MAX;
-	uint64_t diff_nsec = 0, a, b;
+	uint32_t best_diff_nsec = INT32_MAX;
+	uint32_t diff_nsec = 0, a, b;
 	int best_capture_rate = 1;
 
+	a = video_frmival_nsec(frmival) / USEC_PER_MSEC;
+
 	/*
 	 * Try to figure out a frameinterval setting allow to reach as close as
 	 * possible to the request. At first without relying on DCMI frame control,
@@ -392,9 +394,8 @@ static int video_stm32_dcmi_set_frmival(const struct device *dev, struct video_f
 		fie.discrete.numerator = frmival->numerator;
 		fie.discrete.denominator = frmival->denominator * capture_rate;
 
-		a = video_frmival_nsec(&fie.discrete);
 		video_closest_frmival(config->sensor_dev, &fie);
-		b = video_frmival_nsec(&fie.discrete);
+		b = video_frmival_nsec(&fie.discrete) * capture_rate / USEC_PER_MSEC;
 		diff_nsec = a > b ? a - b : b - a;
 		if (diff_nsec < best_diff_nsec) {
 			best_diff_nsec = diff_nsec;