diff --git a/media/codec2/core/include/C2Config.h b/media/codec2/core/include/C2Config.h
index 417b261..9a3399d 100644
--- a/media/codec2/core/include/C2Config.h
+++ b/media/codec2/core/include/C2Config.h
@@ -2016,7 +2016,8 @@
 constexpr char C2_PARAMKEY_MAX_CODED_CHANNEL_COUNT[] = "coded.max-channel-count";
 
 /**
- * Audio channel mask. Used by decoder to express audio channel mask of decoded content.
+ * Audio channel mask. Used by decoder to express audio channel mask of decoded content,
+ * or by encoder for the channel mask of the encoded content once decoded.
  * Channel representation is specified according to the Java android.media.AudioFormat
  * CHANNEL_OUT_* constants.
  */
diff --git a/media/codec2/sfplugin/CCodecConfig.cpp b/media/codec2/sfplugin/CCodecConfig.cpp
index a893bc0..6c10549 100644
--- a/media/codec2/sfplugin/CCodecConfig.cpp
+++ b/media/codec2/sfplugin/CCodecConfig.cpp
@@ -940,6 +940,9 @@
     add(ConfigMapper(KEY_CHANNEL_MASK, C2_PARAMKEY_CHANNEL_MASK, "value")
         .limitTo(D::AUDIO & D::DECODER & D::READ));
 
+    add(ConfigMapper(KEY_CHANNEL_MASK, C2_PARAMKEY_CHANNEL_MASK, "value")
+        .limitTo(D::AUDIO & D::ENCODER & D::CONFIG));
+
     add(ConfigMapper(KEY_AAC_SBR_MODE, C2_PARAMKEY_AAC_SBR_MODE, "value")
         .limitTo(D::AUDIO & D::ENCODER & (D::CONFIG | D::PARAM | D::READ))
         .withMapper([](C2Value v) -> C2Value {