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diff --git a/raul/TimeSlice.hpp b/raul/TimeSlice.hpp
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+/*
+  This file is part of Raul.
+  Copyright 2007-2012 David Robillard <http://drobilla.net>
+
+  Raul is free software: you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation, either version 3 of the License, or any later version.
+
+  Raul is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with Raul.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RAUL_TIMESLICE_HPP
+#define RAUL_TIMESLICE_HPP
+
+#include "raul/Noncopyable.hpp"
+#include "raul/TimeStamp.hpp"
+
+#include <cassert>
+#include <cmath>
+
+namespace Raul {
+
+/* FIXME: all the conversion here is wrong now */
+
+/** A duration of time, with conversion between tick time and beat time.
+ *
+ * This is a slice along a single timeline (ie t=0 in ticks and t=0 in beats
+ * are equal).  Relation to an external time base (e.g. Jack frame time) is
+ * represented by frame_offset (the idea is that this holds all the information
+ * necessary for passing to run() methods so they know the current state of
+ * things WRT time).
+ *
+ * This class handles conversion between two units of time: musical
+ * (beat) time, and real (tick) time.  Real time is discrete, the smallest
+ * unit of time is the 'tick' (usually audio frames or MIDI ticks).  Beat time
+ * is stored as a double (to be independent of any rates or timer precision).
+ *
+ * This caches as many values as possible to make calls less expensive, pass it
+ * around by reference, not value.
+ *
+ * \ingroup raul
+ */
+class TimeSlice : public Noncopyable {
+public:
+	TimeSlice(uint32_t rate, uint32_t ppqn, double bpm)
+		: _tick_rate(rate)
+		, _beat_rate(60.0/bpm)
+		, _start_ticks(Raul::TimeUnit(Raul::TimeUnit::FRAMES, rate), 0, 0)
+		, _length_ticks(TimeUnit(TimeUnit::FRAMES, rate), 0, 0)
+		, _start_beats(TimeUnit(TimeUnit::BEATS, ppqn), 0, 0)
+		, _length_beats(TimeUnit(TimeUnit::BEATS, ppqn), 0, 0)
+		, _offset_ticks(TimeUnit(TimeUnit::FRAMES, rate), 0, 0)
+	{}
+
+	/** Set the start and length of the slice.
+	 *
+	 * Note that external offset is not affected by this, don't forget to reset
+	 * the offset each cycle!
+	 */
+	void set_slice(TimeStamp start, TimeDuration length) {
+		assert(start.unit() == ticks_unit());
+		assert(length.unit() == ticks_unit());
+		_start_ticks = start;
+		_length_ticks = length;
+		update_beat_time();
+	}
+
+	void set_length(TimeDuration length) {
+		assert(length.unit() == ticks_unit());
+		_length_ticks = length;
+		_length_beats = ticks_to_beats(_length_ticks);
+	}
+
+	bool contains(TimeStamp time) const {
+		return (time >= start_ticks() && time < start_ticks() + length_ticks());
+	}
+
+	double tick_rate() const { return _tick_rate; }
+	double beat_rate() const { return _beat_rate; }
+	double bpm()       const { return 60/_beat_rate; }
+
+	void set_tick_rate(double tick_rate) {
+		_tick_rate = tick_rate;
+		update_beat_time();
+	}
+
+	void set_bpm(double bpm) {
+		_beat_rate = 60.0/bpm;
+		update_beat_time();
+	}
+
+	inline TimeStamp beats_to_seconds(TimeStamp beats) const {
+		return TimeStamp(real_unit(), beats.to_double() * 1/_beat_rate);
+	}
+
+	inline TimeStamp beats_to_ticks(TimeStamp beats) const {
+		return TimeStamp(ticks_unit(), beats.to_double() * _beat_rate * _tick_rate);
+	}
+
+	inline TimeStamp ticks_to_seconds(TimeStamp ticks) const {
+		return {real_unit(), ticks.ticks() * 1/_tick_rate};
+	}
+
+	inline TimeStamp ticks_to_beats(TimeStamp ticks) const {
+		return {beats_unit(), ticks.ticks() * 1/_tick_rate * _beat_rate};
+	}
+
+	/** Start of current sub-cycle in ticks */
+	inline TimeStamp start_ticks() const { return _start_ticks; }
+
+	/** Length of current sub-cycle in ticks */
+	inline TimeDuration length_ticks() const { return _length_ticks; }
+
+	/** Start of current sub-cycle in beats */
+	inline TimeStamp start_beats() const { return _start_beats; }
+
+	/** Length of current sub-cycle in beats */
+	inline TimeDuration length_beats() const { return _length_beats; }
+
+	/** Set the offset between real-time and timeslice-time. */
+	inline void set_offset(TimeDuration offset) { _offset_ticks = offset; }
+
+	/** Offset relative to external (e.g Jack) time */
+	inline TimeDuration offset_ticks() const { return _offset_ticks; }
+
+	inline TimeUnit beats_unit() const { return _start_beats.unit(); }
+	inline TimeUnit ticks_unit() const { return _start_ticks.unit(); }
+	inline TimeUnit real_unit()  const { return {TimeUnit::SECONDS, 0}; }
+
+private:
+	inline void update_beat_time() {
+		_start_beats  = ticks_to_beats(_start_ticks);
+		_length_beats = ticks_to_beats(_length_ticks);
+	}
+
+	// Rate/Tempo
+	double _tick_rate; ///< Tick rate in Hz (e.g. sample rate)
+	double _beat_rate; ///< Beat rate in Hz
+
+	// Current time
+	TimeStamp    _start_ticks;  ///< Current window start in ticks
+	TimeDuration _length_ticks; ///< Current window length in ticks
+	TimeStamp    _start_beats;  ///< Current window start in beats
+	TimeDuration _length_beats; ///< Current window length in beats
+
+	TimeDuration _offset_ticks; ///< Offset to global time
+};
+
+} // namespace Raul
+
+#endif // RAUL_TIMESLICE_HPP