diff --git a/common/JackDriver.cpp b/common/JackDriver.cpp
index 8cbd120b..a334d998 100644
--- a/common/JackDriver.cpp
+++ b/common/JackDriver.cpp
@@ -84,8 +84,8 @@ int JackDriver::Open()
 
 int JackDriver::Open(jack_nframes_t nframes,
                      jack_nframes_t samplerate,
-                     int capturing,
-                     int playing,
+                     bool capturing,
+                     bool playing,
                      int inchannels,
                      int outchannels,
                      bool monitor,
diff --git a/common/JackDriver.h b/common/JackDriver.h
index 9739634a..945af893 100644
--- a/common/JackDriver.h
+++ b/common/JackDriver.h
@@ -53,8 +53,8 @@ class EXPORT JackDriverInterface
 
         virtual int Open(jack_nframes_t nframes,
                          jack_nframes_t samplerate,
-                         int capturing,
-                         int playing,
+                         bool capturing,
+                         bool playing,
                          int inchannels,
                          int outchannels,
                          bool monitor,
@@ -147,8 +147,8 @@ class EXPORT JackDriver : public JackDriverClient
 
         virtual int Open(jack_nframes_t nframes,
                          jack_nframes_t samplerate,
-                         int capturing,
-                         int playing,
+                         bool capturing,
+                         bool playing,
                          int inchannels,
                          int outchannels,
                          bool monitor,
diff --git a/common/JackDummyDriver.cpp b/common/JackDummyDriver.cpp
index 82af7b03..95fbecf8 100644
--- a/common/JackDummyDriver.cpp
+++ b/common/JackDummyDriver.cpp
@@ -31,8 +31,8 @@ namespace Jack
 
 int JackDummyDriver::Open(jack_nframes_t nframes,
                           jack_nframes_t samplerate,
-                          int capturing,
-                          int playing,
+                          bool capturing,
+                          bool playing,
                           int inchannels,
                           int outchannels,
                           bool monitor,
diff --git a/common/JackDummyDriver.h b/common/JackDummyDriver.h
index 38ce03df..33d35f65 100644
--- a/common/JackDummyDriver.h
+++ b/common/JackDummyDriver.h
@@ -48,8 +48,8 @@ class JackDummyDriver : public JackAudioDriver
 
         int Open(jack_nframes_t frames_per_cycle,
                  jack_nframes_t rate,
-                 int capturing,
-                 int playing,
+                 bool capturing,
+                 bool playing,
                  int chan_in,
                  int chan_out,
                  bool monitor,
diff --git a/common/JackThreadedDriver.h b/common/JackThreadedDriver.h
index 0d059a4a..de22a002 100644
--- a/common/JackThreadedDriver.h
+++ b/common/JackThreadedDriver.h
@@ -51,8 +51,8 @@ class JackThreadedDriver : public JackDriverClientInterface, public JackRunnable
 
         virtual int Open(jack_nframes_t nframes,
                          jack_nframes_t samplerate,
-                         int capturing,
-                         int playing,
+                         bool capturing,
+                         bool playing,
                          int inchannels,
                          int outchannels,
                          bool monitor,
diff --git a/linux/alsa/JackAlsaDriver.cpp b/linux/alsa/JackAlsaDriver.cpp
index f6c4c864..58e444c6 100644
--- a/linux/alsa/JackAlsaDriver.cpp
+++ b/linux/alsa/JackAlsaDriver.cpp
@@ -2180,16 +2180,16 @@ int JackAlsaDriver::Detach()
 int JackAlsaDriver::Open(jack_nframes_t nframes,
 						 jack_nframes_t user_nperiods,
                          jack_nframes_t samplerate,
-						 int hw_monitoring,
-						 int hw_metering,
-                         int capturing,
-                         int playing,
+						 bool hw_monitoring,
+						 bool hw_metering,
+                         bool capturing,
+                         bool playing,
 						 DitherAlgorithm dither,
-						 int soft_mode, 
-						 int monitor,
+						 bool soft_mode, 
+						 bool monitor,
                          int inchannels,
                          int outchannels,
-						 int shorts_first,
+						 bool shorts_first,
                          const char* capture_driver_name,
 						 const char* playback_driver_name,
 						 jack_nframes_t capture_latency,
diff --git a/linux/alsa/JackAlsaDriver.h b/linux/alsa/JackAlsaDriver.h
index bfd36e7c..2bd6ba92 100644
--- a/linux/alsa/JackAlsaDriver.h
+++ b/linux/alsa/JackAlsaDriver.h
@@ -126,16 +126,16 @@ class JackAlsaDriver : public JackAudioDriver
         int Open(jack_nframes_t nframes,
 				 jack_nframes_t user_nperiods,
 				 jack_nframes_t samplerate,
-				 int hw_monitoring,
-				 int hw_metering,
-				 int capturing,
-				 int playing,
+				 bool hw_monitoring,
+				 bool hw_metering,
+				 bool capturing,
+				 bool playing,
 				 DitherAlgorithm dither,
-				 int soft_mode, 
-				 int monitor,
+				 bool soft_mode, 
+				 bool monitor,
 				 int inchannels,
 				 int outchannels,
-				 int shorts_first,
+				 bool shorts_first,
 				 const char* capture_driver_name,
 				 const char* playback_driver_name,
 				 jack_nframes_t capture_latency,
diff --git a/macosx/JackCoreAudioDriver.cpp b/macosx/JackCoreAudioDriver.cpp
index b6440009..36aa7d83 100644
--- a/macosx/JackCoreAudioDriver.cpp
+++ b/macosx/JackCoreAudioDriver.cpp
@@ -517,8 +517,8 @@ bool JackCoreAudioDriver::Execute()
 
 int JackCoreAudioDriver::Open(jack_nframes_t nframes,
                               jack_nframes_t samplerate,
-                              int capturing,
-                              int playing,
+                              bool capturing,
+                              bool playing,
                               int inchannels,
                               int outchannels,
                               bool monitor,
diff --git a/macosx/JackCoreAudioDriver.h b/macosx/JackCoreAudioDriver.h
index a26e0f23..a3d2fe07 100644
--- a/macosx/JackCoreAudioDriver.h
+++ b/macosx/JackCoreAudioDriver.h
@@ -113,8 +113,8 @@ class JackCoreAudioDriver : public JackAudioDriver,  public JackRunnableInterfac
 
         int Open(jack_nframes_t frames_per_cycle,
                  jack_nframes_t rate,
-                 int capturing,
-                 int playing,
+                 bool capturing,
+                 bool playing,
                  int chan_in,
                  int chan_out,
                  bool monitor,
diff --git a/windows/JackPortAudioDriver.cpp b/windows/JackPortAudioDriver.cpp
index 0162318e..5cf8c7fa 100644
--- a/windows/JackPortAudioDriver.cpp
+++ b/windows/JackPortAudioDriver.cpp
@@ -247,8 +247,8 @@ int JackPortAudioDriver::Write()
 
 int JackPortAudioDriver::Open(jack_nframes_t nframes,
                               jack_nframes_t samplerate,
-                              int capturing,
-                              int playing,
+                              bool capturing,
+                              bool playing,
                               int inchannels,
                               int outchannels,
                               bool monitor,
diff --git a/windows/JackPortAudioDriver.h b/windows/JackPortAudioDriver.h
index 80070ec1..0c40ddd3 100644
--- a/windows/JackPortAudioDriver.h
+++ b/windows/JackPortAudioDriver.h
@@ -63,8 +63,8 @@ class JackPortAudioDriver : public JackAudioDriver
 
         int Open(jack_nframes_t frames_per_cycle,
                  jack_nframes_t rate,
-                 int capturing,
-                 int playing,
+                 bool capturing,
+                 bool playing,
                  int chan_in,
                  int chan_out,
                  bool monitor,