diff --git a/lib_com/options.h b/lib_com/options.h
index ff4cf5f346ae26f9eb7d021c6be59ef90fdb658a..5906991cdfdee9af54778d11f6c64f32df921be8 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -151,6 +151,7 @@
 #define CORECODER_BITRATE_SWITCHING                     /* Issue 133: support bitrate switching in core-coder */
 #define ISM_BITRATE_SWITCHING                           /* Issue 115: Support for Bitrate Switching in ISM */
 #define SBA_SPAR_HARM                                   /* Issue 92: maintenance of the SBA SPAR functions */
+#define FIX_155_HP20_ISSUE                              /* Issue 155: apply hp20 on all input channels instead of just 2 channels */
 
 
 
diff --git a/lib_enc/ivas_init_enc.c b/lib_enc/ivas_init_enc.c
index e4db2ce2a16b6a5a6c3fb006ac7ff824a289fdcd..8d79594c7e34de35d1dd37a544f7c683fd4d7a4a 100644
--- a/lib_enc/ivas_init_enc.c
+++ b/lib_enc/ivas_init_enc.c
@@ -190,6 +190,12 @@ int16_t getNumChanAnalysis(
     {
         n = st_ivas->hEncoderConfig->nchan_inp;
     }
+#ifdef FIX_155_HP20_ISSUE
+    else if ( st_ivas->hEncoderConfig->ivas_format == ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_PARAM )
+    {
+        n = st_ivas->hEncoderConfig->nchan_inp;
+    }
+#endif
 
     return n;
 }