diff --git a/include/ksmedia.h b/include/ksmedia.h
index da69b31..4027596 100644
--- a/include/ksmedia.h
+++ b/include/ksmedia.h
@@ -25,6 +25,8 @@
 
 DEFINE_GUID(KSDATAFORMAT_SUBTYPE_PCM, 0x00000001, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71);
 DEFINE_GUID(KSDATAFORMAT_SUBTYPE_IEEE_FLOAT, 0x00000003, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71);
+DEFINE_GUID(KSDATAFORMAT_SUBTYPE_MULAW, 0x00000007, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71);
+DEFINE_GUID(KSDATAFORMAT_SUBTYPE_ALAW, 0x00000006, 0x0000, 0x0010, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71);
 
 #define KSAUDIO_SPEAKER_DIRECTOUT 0
 #define KSAUDIO_SPEAKER_MONO SPEAKER_FRONT_CENTER