JACK doesn't like it if you set a slow-sync callback and don't act like a slow-sync client...

Mixer/Engine/Engine.C

@@ -74,24 +74,6 @@ Engine::buffer_size ( nframes_t )
     return 0;
 }
 
-int Engine::sync ( jack_transport_state_t, jack_position_t * )
-{
-    return 0;
-}
-
-void
-Engine::timebase ( jack_transport_state_t, jack_nframes_t, jack_position_t *, int )
-{
-
-
-}
-
-void
-Engine::timebase ( jack_transport_state_t, jack_nframes_t, jack_position_t * )
-{
-
-}
-
 /* THREAD: RT */
 int
 Engine::process ( nframes_t nframes )

Mixer/Engine/Engine.H

@@ -39,10 +39,7 @@ class Engine : public JACK::Client, public Mutex
 
     void shutdown ( void );
     int process ( nframes_t nframes );
-    int sync ( jack_transport_state_t state, jack_position_t *pos );
     int xrun ( void );
-    void timebase ( jack_transport_state_t state, jack_nframes_t nframes, jack_position_t *pos );
-    void timebase ( jack_transport_state_t state, jack_nframes_t nframes, jack_position_t *pos, int new_pos );
     void freewheel ( bool yes );
     int buffer_size ( nframes_t nframes );
     void thread_init ( void );

Timeline/main.C

@@ -136,7 +136,7 @@ main ( int argc, char **argv )
 
     const char *jack_name;
 
-    if ( ! ( jack_name = engine->init( APP_NAME ) ) )
+    if ( ! ( jack_name = engine->init( APP_NAME, JACK::Client::SLOW_SYNC | JACK::Client::TIMEBASE_MASTER ) ) )
         FATAL( "Could not connect to JACK!" );
 
     timeline->sample_rate( engine->sample_rate() );

nonlib/JACK/Client.C

@@ -113,7 +113,7 @@ namespace JACK
 /** Connect to JACK using client name /client_name/. Return a static
  * pointer to actual name as reported by JACK */
     const char *
-    Client::init ( const char *client_name )
+    Client::init ( const char *client_name, unsigned int opts )
     {
         if (( _client = jack_client_open ( client_name, (jack_options_t)0, NULL )) == 0 )
             return NULL;
@@ -128,8 +128,10 @@ namespace JACK
 
         /* FIXME: should we wait to register this until after the project
            has been loaded (and we have disk threads running)? */
+        if ( opts & SLOW_SYNC )
             set_callback( sync );
 
+        if ( opts & TIMEBASE_MASTER )
             jack_set_timebase_callback( _client, 0, &Client::timebase, this );
 
         jack_on_shutdown( _client, &Client::shutdown, this );

nonlib/JACK/Client.H

@@ -31,7 +31,6 @@ namespace JACK
     class Port;
     class Client
     {
-
         std::list <JACK::Port*> _active_ports;
 
         jack_client_t *_client;
@@ -46,11 +45,11 @@ namespace JACK
         static int process ( nframes_t nframes, void *arg );
         virtual int process ( nframes_t nframes ) = 0;
         static int sync ( jack_transport_state_t state, jack_position_t *pos, void *arg );
-        virtual int sync ( jack_transport_state_t state, jack_position_t *pos ) = 0;
+        virtual int sync ( jack_transport_state_t, jack_position_t * ) { return 1; }
         static int xrun ( void *arg );
         virtual int xrun ( void ) = 0;
         static void timebase ( jack_transport_state_t state, jack_nframes_t nframes, jack_position_t *pos, int new_pos, void *arg );
-        virtual void timebase ( jack_transport_state_t state, jack_nframes_t nframes, jack_position_t *pos, int new_pos ) = 0;
+        virtual void timebase ( jack_transport_state_t, jack_nframes_t, jack_position_t *, int ) { }
         static void freewheel ( int yes, void *arg );
         virtual void freewheel ( bool yes ) = 0;
         static int buffer_size ( nframes_t nframes, void *arg );
@@ -75,6 +74,10 @@ namespace JACK
 
     public:
 
+        enum options { DEFAULT = 0,
+                       SLOW_SYNC = 1 << 0,
+                       TIMEBASE_MASTER = 1 << 1 };
+
         jack_client_t * jack_client ( void ) { return _client; }
 
         void port_added ( JACK::Port * p );
@@ -83,7 +86,7 @@ namespace JACK
         Client ( );
         virtual ~Client ( );
 
-        const char * init ( const char *client_name );
+        const char * init ( const char *client_name, unsigned int opts = 0 );
         const char * name ( const char * );
 
         nframes_t nframes ( void ) const { return jack_get_buffer_size( _client ); }