code: public TimecodeRange toOffset(Timecode reference)
  	{
  		if (reference.gt(start))
  			throw new IllegalArgumentException("Reference timecode " + reference + " is before start " + start + "!");
  
  		final SampleCount samples = reference.getSampleCount();
  
  		return subtract(samples);
  	}
docs: Constructs a new TimecodeRange where the values are expressed as offsets from <code>reference</code>.
  
  @param reference
  the reference timecode. <b>Must be less than or equal to the start timecode for this range</b>
  
  @return