diff --git a/libs/ardour/ardour/midi_buffer.h b/libs/ardour/ardour/midi_buffer.h
index b6966faa06..2e2cbf6504 100644
--- a/libs/ardour/ardour/midi_buffer.h
+++ b/libs/ardour/ardour/midi_buffer.h
@@ -56,14 +56,16 @@ public:
 	bool merge_in_place(const MidiBuffer &other);
 
 	template<typename BufferType, typename EventType>
-	class iterator_base {
+		class iterator_base
+	{
 	public:
-		iterator_base<BufferType, EventType>(BufferType& b, framecnt_t o) 
-		     : buffer(&b), offset(o) {}
-                iterator_base<BufferType, EventType>(const iterator_base<BufferType,EventType>& o) 
-		     : buffer (o.buffer), offset(o.offset) {}
-	    
-	        inline iterator_base<BufferType,EventType> operator= (const iterator_base<BufferType,EventType>& o) {
+		iterator_base<BufferType, EventType>(BufferType& b, framecnt_t o)
+			: buffer(&b), offset(o) {}
+
+		iterator_base<BufferType, EventType>(const iterator_base<BufferType,EventType>& o)
+			: buffer (o.buffer), offset(o.offset) {}
+
+		inline iterator_base<BufferType,EventType> operator= (const iterator_base<BufferType,EventType>& o) {
 			if (&o != this) {
 				buffer = o.buffer;
 				offset = o.offset;
@@ -79,6 +81,7 @@ public:
 					*((TimeType*)(buffer->_data + offset)),
 					event_size, ev_start);
 		}
+
 		inline EventType operator*() {
 			uint8_t* ev_start = buffer->_data + offset + sizeof(TimeType);
 			int event_size = Evoral::midi_event_size(ev_start);
@@ -99,12 +102,15 @@ public:
 			offset += sizeof(TimeType) + event_size;
 			return *this;
 		}
+
 		inline bool operator!=(const iterator_base<BufferType, EventType>& other) const {
 			return (buffer != other.buffer) || (offset != other.offset);
 		}
+
 		inline bool operator==(const iterator_base<BufferType, EventType>& other) const {
 			return (buffer == other.buffer) && (offset == other.offset);
 		}
+
 		BufferType*     buffer;
 		size_t          offset;
 	};
@@ -118,7 +124,7 @@ public:
 	const_iterator begin() const { return const_iterator(*this, 0); }
 	const_iterator end()   const { return const_iterator(*this, _size); }
 
-        iterator erase(const iterator& i) {
+	iterator erase(const iterator& i) {
 		assert (i.buffer == this);
 		uint8_t* ev_start = _data + i.offset + sizeof (TimeType);
 		int event_size = Evoral::midi_event_size (ev_start);
@@ -161,7 +167,7 @@ public:
 	 * its MIDI status byte.
 	 */
 	static bool second_simultaneous_midi_byte_is_first (uint8_t, uint8_t);
-	
+
 private:
 	friend class iterator_base< MidiBuffer, Evoral::MIDIEvent<TimeType> >;
 	friend class iterator_base< const MidiBuffer, const Evoral::MIDIEvent<TimeType> >;
@@ -170,7 +176,6 @@ private:
 	pframes_t _size;
 };
 
-
 } // namespace ARDOUR
 
 #endif // __ardour_midi_buffer_h__