-/**
- * Add two matrices together. result = m1 + m2.
- *
- * @param m1 9-item transformation matrix
- * @param m2 9-item transformation matrix
- * @param result 9-item transformation matrix
- */
-void avfilter_add_matrix(const float *m1, const float *m2, float *result);
-
-/**
- * Subtract one matrix from another. result = m1 - m2.
- *
- * @param m1 9-item transformation matrix
- * @param m2 9-item transformation matrix
- * @param result 9-item transformation matrix
- */
-void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
-
-/**
- * Multiply a matrix by a scalar value. result = m1 * scalar.
- *
- * @param m1 9-item transformation matrix
- * @param scalar a number
- * @param result 9-item transformation matrix
- */
-void avfilter_mul_matrix(const float *m1, float scalar, float *result);
-