func (s *Stream) Length() int64 {
	if s.resampling != nil {
		return s.resampling.Length()
	}
	return s.orig.Length()
}
func (s *Stream) Length() int64 {
	if s.resampling != nil {
		return s.resampling.Length()
	}
	return s.orig.Length()
}
// Length returns the size of decoded stream in bytes.