const AnalogSegment::Envelope &e0 = s.envelope_levels_[0];
BOOST_CHECK_EQUAL(e0.length, 1);
BOOST_CHECK_EQUAL(e0.data_length, AnalogSegment::EnvelopeDataUnit);
const AnalogSegment::Envelope &e0 = s.envelope_levels_[0];
BOOST_CHECK_EQUAL(e0.length, 1);
BOOST_CHECK_EQUAL(e0.data_length, AnalogSegment::EnvelopeDataUnit);