const fix.

diff --git a/src/lib/audio_filter.cc b/src/lib/audio_filter.cc
index 2cf1cf6047ac4b3e00adb5d6812ac8bd1ad5061f..10f3849dffa3aa271b9521b14c4af24d9f1533e0 100644 (file)
--- a/src/lib/audio_filter.cc
+++ b/src/lib/audio_filter.cc
@@ -67,7 +67,7 @@ AudioFilter::sinc_blackman (float cutoff, bool invert) const
 }
 
 shared_ptr<AudioBuffers>
-AudioFilter::run (shared_ptr<AudioBuffers> in)
+AudioFilter::run (shared_ptr<const AudioBuffers> in)
 {
        shared_ptr<AudioBuffers> out (new AudioBuffers (in->channels(), in->frames()));