Keep track of capture duration

libs/ardour/ardour/session.h

@@ -303,6 +303,9 @@ public:
 
 	bool have_captured() const { return _have_captured; }
 
+	samplecnt_t capture_duration () const { return _capture_duration; }
+	unsigned int capture_xruns () const { return _capture_xruns; }
+
 	void refill_all_track_buffers ();
 	Butler* butler() { return _butler; }
 	void butler_transport_work (bool have_process_lock = false);
@@ -1370,6 +1373,8 @@ private:
 	samplecnt_t             _worst_route_latency;
 	uint32_t                _send_latency_changes;
 	bool                    _have_captured;
+	samplecnt_t             _capture_duration;
+	unsigned int            _capture_xruns;
 	bool                    _non_soloed_outs_muted;
 	bool                    _listening;
 	uint32_t                _listen_cnt;

libs/ardour/session.cc

@@ -208,6 +208,8 @@ Session::Session (AudioEngine &eng,
 	, _worst_route_latency (0)
 	, _send_latency_changes (0)
 	, _have_captured (false)
+	, _capture_duration (0)
+	, _capture_xruns (0)
 	, _non_soloed_outs_muted (false)
 	, _listening (false)
 	, _listen_cnt (0)
@@ -1890,6 +1892,9 @@ Session::enable_record ()
 				set_track_monitor_input_status (true);
 			}
 
+			_capture_duration = 0;
+			_capture_xruns = 0;
+
 			RecordStateChanged ();
 			break;
 		}

libs/ardour/session_process.cc

@@ -216,6 +216,10 @@ Session::process_routes (pframes_t nframes, bool& need_butler)
 	const samplepos_t start_sample = _transport_sample;
 	const samplepos_t end_sample = _transport_sample + floor (nframes * _transport_speed);
 
+	if (actively_recording ()) {
+		_capture_duration += nframes;
+	}
+
 	VCAList v = _vca_manager->vcas ();
 	for (VCAList::const_iterator i = v.begin(); i != v.end(); ++i) {
 		(*i)->automation_run (start_sample, nframes);

libs/ardour/session_transport.cc

@@ -1876,6 +1876,8 @@ Session::xrun_recovery ()
 	Xrun (_transport_sample); /* EMIT SIGNAL */
 
 	if (actively_recording ()) {
+		++_capture_xruns;
+
 		if (Config->get_stop_recording_on_xrun()) {
 
 			/* it didn't actually halt, but we need