diff --git a/libavutil/pca.h b/libavutil/pca.h
index de729840a4..c071c1a72f 100644
--- a/libavutil/pca.h
+++ b/libavutil/pca.h
@@ -23,6 +23,12 @@
  * Principal component analysis
  */
 
+struct PCA *ff_pca_init(int n);
+void ff_pca_free(struct PCA *pca);
+void ff_pca_add(struct PCA *pca, double *v);
+int ff_pca(struct PCA *pca, double *eigenvector, double *eigenvalue);
+
+
 typedef struct PCA{
     int count;
     int n;