diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 0f5809b752..9439be0f41 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -539,8 +539,6 @@ typedef struct EncStats {
     int                 lock_initialized;
 } EncStats;
 
-extern const char *const forced_keyframes_const_names[];
-
 enum {
     KF_FORCE_SOURCE         = 1,
 #if FFMPEG_OPT_FORCE_KF_SOURCE_NO_DROP
diff --git a/fftools/ffmpeg_mux_init.c b/fftools/ffmpeg_mux_init.c
index 033fa6aba8..117b1a4338 100644
--- a/fftools/ffmpeg_mux_init.c
+++ b/fftools/ffmpeg_mux_init.c
@@ -3087,7 +3087,7 @@ finish:
     return ret;
 }
 
-const char *const forced_keyframes_const_names[] = {
+static const char *const forced_keyframes_const_names[] = {
     "n",
     "n_forced",
     "prev_forced_n",