diff --git a/sys/src/avutil/opt.rs b/sys/src/avutil/opt.rs
index c2fa39e..45b5c47 100644
--- a/sys/src/avutil/opt.rs
+++ b/sys/src/avutil/opt.rs
@@ -114,7 +114,7 @@ extern {
 	pub fn av_opt_set_double(obj: *mut c_void, name: *const c_char, val: c_double, search_flags: c_int) -> c_int;
 	pub fn av_opt_set_q(obj: *mut c_void, name: *const c_char, val: AVRational, search_flags: c_int) -> c_int;
 	pub fn av_opt_set_bin(obj: *mut c_void, name: *const c_char, val: *const uint8_t, len: c_int, search_flags: c_int) -> c_int;
-	pub fn av_opt_set_image_size(obj: *mut c_void, name: *const c_char, w: c_int, h: c_int, size: c_int, search_flags: c_int) -> c_int;
+	pub fn av_opt_set_image_size(obj: *mut c_void, name: *const c_char, w: c_int, h: c_int, search_flags: c_int) -> c_int;
 	pub fn av_opt_set_pixel_fmt(obj: *mut c_void, name: *const c_char, fmt: AVPixelFormat, search_flags: c_int) -> c_int;
 	pub fn av_opt_set_sample_fmt(obj: *mut c_void, name: *const c_char, fmt: AVSampleFormat, search_flags: c_int) -> c_int;
 	pub fn av_opt_set_video_rate(obj: *mut c_void, name: *const c_char, val: AVRational, search_flags: c_int) -> c_int;