diff --git a/softhddev.c b/softhddev.c
index 1759109..a27ee33 100644
--- a/softhddev.c
+++ b/softhddev.c
@@ -89,7 +89,7 @@ static char VdpauDecoder = 1;		///< vdpau decoder used
 extern int ConfigAudioBufferTime;	///< config size ms of audio buffer
 extern int ConfigVideoClearOnSwitch;	//<  clear decoder on channel switch
 char ConfigStartX11Server;		///< flag start the x11 server
-static char ConfigStartSuspended;	///< flag to start in suspend mode
+static signed char ConfigStartSuspended;	///< flag to start in suspend mode
 static char ConfigFullscreen;		///< fullscreen modus
 static const char *X11ServerArguments;	///< default command arguments
 static char ConfigStillDecoder;		///< hw/sw decoder for still picture
diff --git a/softhddevice.cpp b/softhddevice.cpp
index b3467a5..ef0cd4b 100644
--- a/softhddevice.cpp
+++ b/softhddevice.cpp
@@ -171,7 +171,7 @@ static volatile int DoMakePrimary;	///< switch primary device to this
 #define NOT_SUSPENDED		0	///< not suspend mode
 #define SUSPEND_NORMAL		1	///< normal suspend mode
 #define SUSPEND_DETACHED	2	///< detached suspend mode
-static char SuspendMode;		///< suspend mode
+static signed char SuspendMode;		///< suspend mode

 //////////////////////////////////////////////////////////////////////////////

diff --git a/video.c b/video.c
index a5b3a5a..bcfcbef 100644
--- a/video.c
+++ b/video.c
@@ -332,7 +332,7 @@ static const VideoModule NoopModule;	///< forward definition of noop module
     /// selected video module
 static const VideoModule *VideoUsedModule = &NoopModule;

-char VideoHardwareDecoder = -1;		///< flag use hardware decoder
+signed char VideoHardwareDecoder = -1;		///< flag use hardware decoder

 static char VideoSurfaceModesChanged;	///< flag surface modes changed

diff --git a/video.h b/video.h
index fa3e44f..0587393 100644
--- a/video.h
+++ b/video.h
@@ -37,7 +37,7 @@ typedef struct __video_stream__ VideoStream;
 //	Variables
 //----------------------------------------------------------------------------

-extern char VideoHardwareDecoder;	///< flag use hardware decoder
+extern signed char VideoHardwareDecoder;	///< flag use hardware decoder
 extern char VideoIgnoreRepeatPict;	///< disable repeat pict warning
 extern int VideoAudioDelay;		///< audio/video delay
 extern char ConfigStartX11Server;	///< flag start the x11 server