diff --git a/common_audio/signal_processing/ilbc_specific_functions.c b/common_audio/signal_processing/ilbc_specific_functions.c
index b75b705..cbdd3dc 100644
--- a/common_audio/signal_processing/ilbc_specific_functions.c
+++ b/common_audio/signal_processing/ilbc_specific_functions.c
@@ -64,7 +64,7 @@
     }
 }
 
-void WebRtcSpl_AddAffineVectorToVector(int16_t *out, int16_t *in,
+void WebRtcSpl_AddAffineVectorToVector(int16_t *out, const int16_t *in,
                                        int16_t gain, int32_t add_constant,
                                        int16_t right_shifts,
                                        size_t vector_length)
@@ -77,7 +77,7 @@
     }
 }
 
-void WebRtcSpl_AffineTransformVector(int16_t *out, int16_t *in,
+void WebRtcSpl_AffineTransformVector(int16_t *out, const int16_t *in,
                                      int16_t gain, int32_t add_constant,
                                      int16_t right_shifts, size_t vector_length)
 {
diff --git a/common_audio/signal_processing/include/signal_processing_library.h b/common_audio/signal_processing/include/signal_processing_library.h
index 33469d4..7b743f0 100644
--- a/common_audio/signal_processing/include/signal_processing_library.h
+++ b/common_audio/signal_processing/include/signal_processing_library.h
@@ -384,13 +384,13 @@
                                   size_t vector_length,
                                   int16_t right_shifts);
 void WebRtcSpl_AddAffineVectorToVector(int16_t* out_vector,
-                                       int16_t* in_vector,
+                                       const int16_t* in_vector,
                                        int16_t gain,
                                        int32_t add_constant,
                                        int16_t right_shifts,
                                        size_t vector_length);
 void WebRtcSpl_AffineTransformVector(int16_t* out_vector,
-                                     int16_t* in_vector,
+                                     const int16_t* in_vector,
                                      int16_t gain,
                                      int32_t add_constant,
                                      int16_t right_shifts,