diff --git a/vp8/vp8_cx_iface.c b/vp8/vp8_cx_iface.c
index 2f394ef0a..f12b88613 100644
--- a/vp8/vp8_cx_iface.c
+++ b/vp8/vp8_cx_iface.c
@@ -1346,10 +1346,10 @@ CODEC_INTERFACE(vpx_codec_vp8_cx) =
     vp8e_destroy,       /* vpx_codec_destroy_fn_t    destroy; */
     vp8e_ctf_maps,      /* vpx_codec_ctrl_fn_map_t  *ctrl_maps; */
     {
-        NOT_IMPLEMENTED,    /* vpx_codec_peek_si_fn_t    peek_si; */
-        NOT_IMPLEMENTED,    /* vpx_codec_get_si_fn_t     get_si; */
-        NOT_IMPLEMENTED,    /* vpx_codec_decode_fn_t     decode; */
-        NOT_IMPLEMENTED,    /* vpx_codec_frame_get_fn_t  frame_get; */
+        NULL,    /* vpx_codec_peek_si_fn_t    peek_si; */
+        NULL,    /* vpx_codec_get_si_fn_t     get_si; */
+        NULL,    /* vpx_codec_decode_fn_t     decode; */
+        NULL,    /* vpx_codec_frame_get_fn_t  frame_get; */
     },
     {
         1,                  /* 1 cfg map */
@@ -1357,7 +1357,7 @@ CODEC_INTERFACE(vpx_codec_vp8_cx) =
         vp8e_encode,        /* vpx_codec_encode_fn_t      encode; */
         vp8e_get_cxdata,    /* vpx_codec_get_cx_data_fn_t   frame_get; */
         vp8e_set_config,
-        NOT_IMPLEMENTED,
+        NULL,
         vp8e_get_preview,
         vp8e_mr_alloc_mem,
     } /* encoder functions */
diff --git a/vp8/vp8_dx_iface.c b/vp8/vp8_dx_iface.c
index 0deda507f..05f32ba20 100644
--- a/vp8/vp8_dx_iface.c
+++ b/vp8/vp8_dx_iface.c
@@ -814,15 +814,15 @@ CODEC_INTERFACE(vpx_codec_vp8_dx) =
         vp8_get_si,       /* vpx_codec_get_si_fn_t     get_si; */
         vp8_decode,       /* vpx_codec_decode_fn_t     decode; */
         vp8_get_frame,    /* vpx_codec_frame_get_fn_t  frame_get; */
-        NOT_IMPLEMENTED,
+        NULL,
     },
     { /* encoder functions */
         0,
-        NOT_IMPLEMENTED,
-        NOT_IMPLEMENTED,
-        NOT_IMPLEMENTED,
-        NOT_IMPLEMENTED,
-        NOT_IMPLEMENTED,
-        NOT_IMPLEMENTED
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL,
+        NULL
     }
 };
diff --git a/vp9/vp9_cx_iface.c b/vp9/vp9_cx_iface.c
index 171605390..752cd0d10 100644
--- a/vp9/vp9_cx_iface.c
+++ b/vp9/vp9_cx_iface.c
@@ -1354,11 +1354,11 @@ CODEC_INTERFACE(vpx_codec_vp9_cx) = {
   encoder_destroy,    // vpx_codec_destroy_fn_t
   encoder_ctrl_maps,  // vpx_codec_ctrl_fn_map_t
   {  // NOLINT
-    NOT_IMPLEMENTED,  // vpx_codec_peek_si_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_get_si_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_decode_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_frame_get_fn_t
-    NOT_IMPLEMENTED   // vpx_codec_set_fb_fn_t
+    NULL,  // vpx_codec_peek_si_fn_t
+    NULL,  // vpx_codec_get_si_fn_t
+    NULL,  // vpx_codec_decode_fn_t
+    NULL,  // vpx_codec_frame_get_fn_t
+    NULL   // vpx_codec_set_fb_fn_t
   },
   {  // NOLINT
     1,                      // 1 cfg map
@@ -1366,8 +1366,8 @@ CODEC_INTERFACE(vpx_codec_vp9_cx) = {
     encoder_encode,         // vpx_codec_encode_fn_t
     encoder_get_cxdata,     // vpx_codec_get_cx_data_fn_t
     encoder_set_config,     // vpx_codec_enc_config_set_fn_t
-    NOT_IMPLEMENTED,        // vpx_codec_get_global_headers_fn_t
+    NULL,        // vpx_codec_get_global_headers_fn_t
     encoder_get_preview,    // vpx_codec_get_preview_frame_fn_t
-    NOT_IMPLEMENTED         // vpx_codec_enc_mr_get_mem_loc_fn_t
+    NULL         // vpx_codec_enc_mr_get_mem_loc_fn_t
   }
 };
diff --git a/vp9/vp9_dx_iface.c b/vp9/vp9_dx_iface.c
index bb2bb10d7..05d61c8a0 100644
--- a/vp9/vp9_dx_iface.c
+++ b/vp9/vp9_dx_iface.c
@@ -647,12 +647,12 @@ CODEC_INTERFACE(vpx_codec_vp9_dx) = {
   },
   { // NOLINT
     0,
-    NOT_IMPLEMENTED,  // vpx_codec_enc_cfg_map_t
-    NOT_IMPLEMENTED,  // vpx_codec_encode_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_get_cx_data_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_enc_config_set_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_get_global_headers_fn_t
-    NOT_IMPLEMENTED,  // vpx_codec_get_preview_frame_fn_t
-    NOT_IMPLEMENTED   // vpx_codec_enc_mr_get_mem_loc_fn_t
+    NULL,  // vpx_codec_enc_cfg_map_t
+    NULL,  // vpx_codec_encode_fn_t
+    NULL,  // vpx_codec_get_cx_data_fn_t
+    NULL,  // vpx_codec_enc_config_set_fn_t
+    NULL,  // vpx_codec_get_global_headers_fn_t
+    NULL,  // vpx_codec_get_preview_frame_fn_t
+    NULL   // vpx_codec_enc_mr_get_mem_loc_fn_t
   }
 };
diff --git a/vpx/internal/vpx_codec_internal.h b/vpx/internal/vpx_codec_internal.h
index 95119dfc7..82bef55c9 100644
--- a/vpx/internal/vpx_codec_internal.h
+++ b/vpx/internal/vpx_codec_internal.h
@@ -286,8 +286,6 @@ typedef const struct vpx_codec_enc_cfg_map {
   vpx_codec_enc_cfg_t cfg;
 } vpx_codec_enc_cfg_map_t;
 
-#define NOT_IMPLEMENTED 0
-
 /*!\brief Decoder algorithm interface interface
  *
  * All decoders \ref MUST expose a variable of this type.