Carla: initial code for plugin latency support

c++/carla-backend/carla_engine.cpp

@@ -22,8 +22,7 @@ CARLA_BACKEND_START_NAMESPACE
 
 // -----------------------------------------------------------------------
 
-unsigned int CarlaPlugin::m_count = 0;
-
+unsigned int   CarlaPlugin::m_count = 0;
 unsigned short CarlaEngine::m_maxPluginNumber = 0;
 
 CarlaEngine::CarlaEngine()

c++/carla-backend/dssi.cpp

@@ -696,6 +696,50 @@ public:
         if (aIns <= 2 && aOuts <= 2 && (aIns == aOuts || aIns == 0 || aOuts == 0))
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
+        // check latency
+        {
+            bool hasLatency = false;
+            uint32_t latency = 0;
+
+            for (uint32_t i=0; i < param.count; i++)
+            {
+                if (param.data[i].type == PARAMETER_LATENCY)
+                {
+                    // pre-run so plugin can update latency control-port
+                    float tmpIn[2][aIns];
+                    float tmpOut[2][aOuts];
+
+                    for (j=0; j < aIn.count; j++)
+                    {
+                        tmpIn[j][0] = 0.0f;
+                        tmpIn[j][1] = 0.0f;
+
+                        if (j == 0 || ! h2)
+                            ldescriptor->connect_port(handle, aIn.rindexes[j], tmpIn[j]);
+                    }
+
+                    for (j=0; j < aOut.count; j++)
+                    {
+                        tmpOut[j][0] = 0.0f;
+                        tmpOut[j][1] = 0.0f;
+
+                        if (j == 0 || ! h2)
+                            ldescriptor->connect_port(handle, aOut.rindexes[j], tmpOut[j]);
+                    }
+
+                    ldescriptor->activate(handle);
+                    ldescriptor->run(handle, 2);
+                    ldescriptor->deactivate(handle);
+
+                    latency = rint(paramBuffers[i]);
+                    hasLatency = true;
+                    break;
+                }
+            }
+
+            // TODO - adjust latency now
+        }
+
         reloadPrograms(true);
 
         x_client->activate();

c++/carla-backend/ladspa.cpp

@@ -665,6 +665,50 @@ public:
         if (aIns <= 2 && aOuts <= 2 && (aIns == aOuts || aIns == 0 || aOuts == 0))
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
+        // check latency
+        {
+            bool hasLatency = false;
+            uint32_t latency = 0;
+
+            for (uint32_t i=0; i < param.count; i++)
+            {
+                if (param.data[i].type == PARAMETER_LATENCY)
+                {
+                    // pre-run so plugin can update latency control-port
+                    float tmpIn[2][aIns];
+                    float tmpOut[2][aOuts];
+
+                    for (j=0; j < aIn.count; j++)
+                    {
+                        tmpIn[j][0] = 0.0f;
+                        tmpIn[j][1] = 0.0f;
+
+                        if (j == 0 || ! h2)
+                            descriptor->connect_port(handle, aIn.rindexes[j], tmpIn[j]);
+                    }
+
+                    for (j=0; j < aOut.count; j++)
+                    {
+                        tmpOut[j][0] = 0.0f;
+                        tmpOut[j][1] = 0.0f;
+
+                        if (j == 0 || ! h2)
+                            descriptor->connect_port(handle, aOut.rindexes[j], tmpOut[j]);
+                    }
+
+                    descriptor->activate(handle);
+                    descriptor->run(handle, 2);
+                    descriptor->deactivate(handle);
+
+                    latency = rint(paramBuffers[i]);
+                    hasLatency = true;
+                    break;
+                }
+            }
+
+            // TODO - adjust latency now
+        }
+
         x_client->activate();
 
         qDebug("LadspaPlugin::reload() - end");

c++/carla-backend/lv2.cpp

@@ -1737,6 +1737,41 @@ public:
                 m_hints |= PLUGIN_CAN_FORCE_STEREO;
         }
 
+        // check latency
+        {
+            bool hasLatency = false;
+            uint32_t latency = 0;
+
+            for (uint32_t i=0; i < param.count; i++)
+            {
+                if (param.data[i].type == PARAMETER_LATENCY)
+                {
+                    // pre-run so plugin can update latency control-port
+                    for (j=0; j < aIn.count; j++)
+                    {
+                        if (j == 0 || ! h2)
+                            descriptor->connect_port(handle, aIn.rindexes[j], nullptr);
+                    }
+
+                    for (j=0; j < aOut.count; j++)
+                    {
+                        if (j == 0 || ! h2)
+                            descriptor->connect_port(handle, aOut.rindexes[j], nullptr);
+                    }
+
+                    descriptor->activate(handle);
+                    descriptor->run(handle, 0);
+                    descriptor->deactivate(handle);
+
+                    latency = rint(paramBuffers[i]);
+                    hasLatency = true;
+                    break;
+                }
+            }
+
+            // TODO - adjust latency now
+        }
+
         reloadPrograms(true);
 
         x_client->activate();

c++/carla-backend/vst.cpp

@@ -729,6 +729,13 @@ public:
         if ((aIns == 0 || aIns == 2) && (aOuts == 0 || aOuts == 2))
             m_hints |= PLUGIN_CAN_FORCE_STEREO;
 
+        // check latency
+        {
+            uint32_t latency = effect->initialDelay;
+
+            // TODO - adjust latency now
+        }
+
         reloadPrograms(true);
 
         x_client->activate();