nested sequences mostly implemented

effects/effects.h

@@ -131,6 +131,7 @@ private:
 class VolumeEffect : public Effect {
 public:
     VolumeEffect(Clip* c);
+    void init();
     void process_audio(quint8* samples, int nb_bytes);
     Effect* copy(Clip* c);
     void load(QXmlStreamReader* stream);
@@ -142,6 +143,7 @@ public:
 class PanEffect : public Effect {
 public:
     PanEffect(Clip* c);
+    void init();
     void process_audio(quint8* samples, int nb_bytes);
     Effect* copy(Clip* c);
     void load(QXmlStreamReader* stream);

effects/paneffect.cpp

@@ -19,6 +19,8 @@ PanEffect::PanEffect(Clip* c) : Effect(c, EFFECT_TYPE_AUDIO, AUDIO_PAN_EFFECT) {
     pan_val->set_value(0);
 }
 
+void PanEffect::init() {}
+
 Effect* PanEffect::copy(Clip* c) {
     PanEffect* p = new PanEffect(c);
     p->pan_val->set_value(pan_val->value());

effects/volumeeffect.cpp

@@ -20,6 +20,8 @@ VolumeEffect::VolumeEffect(Clip* c) : Effect(c, EFFECT_TYPE_AUDIO, AUDIO_VOLUME_
     volume_val->set_value(100);
 }
 
+void VolumeEffect::init() {}
+
 Effect* VolumeEffect::copy(Clip* c) {
     VolumeEffect* v = new VolumeEffect(c);
     v->volume_val->set_value(volume_val->value());