diff --git a/av/codec/codec.pxd b/av/codec/codec.pxd
index 7739f6a57..5ccce4718 100644
--- a/av/codec/codec.pxd
+++ b/av/codec/codec.pxd
@@ -7,8 +7,6 @@ cdef class Codec:
 
     cdef const lib.AVCodec *ptr
     cdef const lib.AVCodecDescriptor *desc
-    cdef readonly bint is_encoder
-
     cdef tuple[HWConfig, ...] _hardware_configs
 
     cdef _init(self, name=?)
diff --git a/av/codec/codec.py b/av/codec/codec.py
index 1c5a6f956..df3466c78 100644
--- a/av/codec/codec.py
+++ b/av/codec/codec.py
@@ -16,7 +16,6 @@
 def wrap_codec(ptr: cython.pointer[cython.const[lib.AVCodec]]) -> Codec:
     codec: Codec = Codec(_cinit_sentinel)
     codec.ptr = ptr
-    codec.is_encoder = lib.av_codec_is_encoder(ptr)
     codec._init()
     return codec
 
@@ -135,8 +134,6 @@ def _init(self, name=None):
             if not self.desc:
                 raise RuntimeError(f"No codec descriptor for {name!r}.")
 
-        self.is_encoder = lib.av_codec_is_encoder(self.ptr)
-
         # Sanity check.
         if self.is_encoder and lib.av_codec_is_decoder(self.ptr):
             raise RuntimeError("%s is both encoder and decoder.")
@@ -154,6 +151,10 @@ def create(self, kind=None):
 
         return CodecContext.create(self)
 
+    @property
+    def is_encoder(self):
+        return bool(lib.av_codec_is_encoder(self.ptr))
+
     @property
     def mode(self):
         return "w" if self.is_encoder else "r"