diff --git a/video/out/gl_common.c b/video/out/gl_common.c
index dd90bee322..1f1f02d4a3 100644
--- a/video/out/gl_common.c
+++ b/video/out/gl_common.c
@@ -341,6 +341,14 @@ static const struct gl_functions gl_functions[] = {
             {0}
         },
     },
+    {
+        .extension = "GLX_SGI_video_sync",
+        .functions = (struct gl_function[]) {
+            DEF_FN_NAMES(GetVideoSync, "glXGetVideoSyncSGI"),
+            DEF_FN_NAMES(WaitVideoSync, "glXWaitVideoSyncSGI"),
+            {0},
+        },
+    },
     // GL legacy functions in GL 1.x - 2.x, removed from GL 3.x
     {
         .ver_core = MPGL_VER(1, 1),
diff --git a/video/out/gl_common.h b/video/out/gl_common.h
index 75ff0d5dfd..2c6ae92224 100644
--- a/video/out/gl_common.h
+++ b/video/out/gl_common.h
@@ -368,6 +368,9 @@ struct GL {
     void (GLAPIENTRY *VDPAUSurfaceAccessNV)(GLvdpauSurfaceNV, GLenum);
     void (GLAPIENTRY *VDPAUMapSurfacesNV)(GLsizei, const GLvdpauSurfaceNV *);
     void (GLAPIENTRY *VDPAUUnmapSurfacesNV)(GLsizei, const GLvdpauSurfaceNV *);
+
+    GLint (GLAPIENTRY *GetVideoSync)(GLuint *);
+    GLint (GLAPIENTRY *WaitVideoSync)(GLint, GLint, unsigned int *);
 };
 
 #endif /* MPLAYER_GL_COMMON_H */