diff --git a/dlls/mciavi32/mciavi.c b/dlls/mciavi32/mciavi.c
index a1380f629ea..dbd2a3b1143 100644
--- a/dlls/mciavi32/mciavi.c
+++ b/dlls/mciavi32/mciavi.c
@@ -91,7 +91,7 @@ static	DWORD	MCIAVI_drvOpen(LPCWSTR str, LPMCI_OPEN_DRIVER_PARMSW modp)
     wma->wCommandTable = mciLoadCommandResource(MCIAVI_hInstance, mciAviWStr, 0);
     modp->wCustomCommandTable = wma->wCommandTable;
     modp->wType = MCI_DEVTYPE_DIGITAL_VIDEO;
-    mciSetDriverData(wma->wDevID, (DWORD)wma);
+    mciSetDriverData(wma->wDevID, (DWORD_PTR)wma);
 
     return modp->wDeviceID;
 }
diff --git a/dlls/mciavi32/mmoutput.c b/dlls/mciavi32/mmoutput.c
index eab8fd51c96..1be8266e8ac 100644
--- a/dlls/mciavi32/mmoutput.c
+++ b/dlls/mciavi32/mmoutput.c
@@ -476,7 +476,7 @@ BOOL    MCIAVI_OpenVideo(WINE_MCIAVI* wma)
     }
 
     if (ICSendMessage(wma->hic, ICM_DECOMPRESS_BEGIN,
-		      (DWORD)wma->inbih, (DWORD)wma->outbih) != ICERR_OK) {
+		      (DWORD_PTR)wma->inbih, (DWORD_PTR)wma->outbih) != ICERR_OK) {
 	WARN("Can't begin decompression\n");
 	return FALSE;
     }
diff --git a/dlls/mciavi32/wnd.c b/dlls/mciavi32/wnd.c
index c2fbb38deae..f447798177e 100644
--- a/dlls/mciavi32/wnd.c
+++ b/dlls/mciavi32/wnd.c
@@ -137,9 +137,9 @@ BOOL    MCIAVI_CreateWindow(WINE_MCIAVI* wma, DWORD dwFlags, LPMCI_DGV_OPEN_PARM
                               dwStyle, rc.left, rc.top,
                               rc.right, rc.bottom,
                               hParent, 0, MCIAVI_hInstance,
-                              (LPVOID)wma->wDevID);
+                              ULongToPtr(wma->wDevID));
     wma->hWndPaint = wma->hWnd;
-    return (BOOL)wma->hWnd;
+    return wma->hWnd != 0;
 }
 
 /***************************************************************************