diff --git a/reactos/include/psdk/ksmedia.h b/reactos/include/psdk/ksmedia.h
index 416598f7b69..37be5e09898 100644
--- a/reactos/include/psdk/ksmedia.h
+++ b/reactos/include/psdk/ksmedia.h
@@ -135,6 +135,15 @@ typedef struct {
 
 //#endif
 
+typedef struct {
+   KSDATARANGE              DataRange;
+   ULONG                    MaximumChannels;
+   ULONG                    MinimumBitsPerSample;
+   ULONG                    MaximumBitsPerSample;
+   ULONG                    MinimumSampleFrequency;
+   ULONG                    MaximumSampleFrequency;
+} KSDATARANGE_AUDIO, *PKSDATARANGE_AUDIO;
+
 // 'vids'
 #define STATIC_KSDATAFORMAT_TYPE_VIDEO \
     0x73646976L, 0x0000, 0x0010, {0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71}
diff --git a/reactos/include/psdk/mmsystem.h b/reactos/include/psdk/mmsystem.h
index c7bd9cede11..359e94e1594 100644
--- a/reactos/include/psdk/mmsystem.h
+++ b/reactos/include/psdk/mmsystem.h
@@ -1660,7 +1660,7 @@ MMRESULT WINAPI waveOutGetVolume(HWAVEOUT,PDWORD);
 MMRESULT WINAPI waveOutSetVolume(HWAVEOUT,DWORD);
 MMRESULT WINAPI waveOutGetErrorTextA(MMRESULT,LPSTR,UINT);
 MMRESULT WINAPI waveOutGetErrorTextW(MMRESULT,LPWSTR,UINT);
-MMRESULT WINAPI waveOutOpen(LPHWAVEOUT,UINT,LPCWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
+MMRESULT WINAPI waveOutOpen(LPHWAVEOUT,UINT,LPWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
 MMRESULT WINAPI waveOutClose(HWAVEOUT);
 MMRESULT WINAPI waveOutPrepareHeader(HWAVEOUT,LPWAVEHDR,UINT);
 MMRESULT WINAPI waveOutUnprepareHeader(HWAVEOUT,LPWAVEHDR,UINT);
@@ -1687,7 +1687,7 @@ MMRESULT WINAPI waveInGetDevCapsA(UINT_PTR,LPWAVEINCAPSA,UINT);
 MMRESULT WINAPI waveInGetDevCapsW(UINT_PTR,LPWAVEINCAPSW,UINT);
 MMRESULT WINAPI waveInGetErrorTextA(MMRESULT,LPSTR,UINT);
 MMRESULT WINAPI waveInGetErrorTextW(MMRESULT,LPWSTR,UINT);
-MMRESULT WINAPI waveInOpen(LPHWAVEIN,UINT,LPCWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
+MMRESULT WINAPI waveInOpen(LPHWAVEIN,UINT,LPWAVEFORMATEX,DWORD_PTR,DWORD_PTR,DWORD);
 MMRESULT WINAPI waveInClose(HWAVEIN);
 MMRESULT WINAPI waveInPrepareHeader(HWAVEIN,LPWAVEHDR,UINT);
 MMRESULT WINAPI waveInUnprepareHeader(HWAVEIN,LPWAVEHDR,UINT);