diff --git a/src/fm_mpx.h b/src/fm_mpx.h
index 81b61be..c65c69c 100644
--- a/src/fm_mpx.h
+++ b/src/fm_mpx.h
@@ -21,6 +21,6 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-extern int fm_mpx_open(char *filename, size_t len);
+extern int fm_mpx_open(char *filename, size_t len, int raw);
 extern int fm_mpx_get_samples(float *mpx_buffer);
-extern int fm_mpx_close();
\ No newline at end of file
+extern int fm_mpx_close();