Index: libhb/audio_resample.c
--- libhb/audio_resample.c.orig
+++ libhb/audio_resample.c
@@ -90,10 +90,12 @@ static int is_mono(uint64_t layout)
     int ii, channel_count;
     int64_t mask;
 
+#ifdef AV_CH_LAYOUT_NATIVE
     if (layout == AV_CH_LAYOUT_NATIVE)
     {
         return 0;
     }
+#endif
     for (ii = 0, channel_count = 0, mask = 1;
          ii < 64 && channel_count < 2; ii++, mask <<= 1)
     {
