diff --git a/src/replayGain.c b/src/replayGain.c
index 49b98dc40..8926138bb 100644
--- a/src/replayGain.c
+++ b/src/replayGain.c
@@ -104,7 +104,7 @@ void freeReplayGainInfo(ReplayGainInfo * info)
 }
 
 void doReplayGain(ReplayGainInfo * info, char *buffer, int bufferSize,
-		  AudioFormat * format)
+		  const AudioFormat * format)
 {
 	mpd_sint16 *buffer16;
 	mpd_sint8 *buffer8;
diff --git a/src/replayGain.h b/src/replayGain.h
index c2d471464..8df6fb0b1 100644
--- a/src/replayGain.h
+++ b/src/replayGain.h
@@ -45,6 +45,6 @@ void freeReplayGainInfo(ReplayGainInfo * info);
 void initReplayGainState(void);
 
 void doReplayGain(ReplayGainInfo * info, char *buffer, int bufferSize,
-		  AudioFormat * format);
+		  const AudioFormat * format);
 
 #endif