ReferenceSequenceFile ref = ReferenceSequenceFileFactory.getReferenceSequenceFile(new File(args[1]));
SAMRecordIterator iterator = reader.iterator();
String refName = iterator.next().getReferenceName();
iterator.close();
ReferenceSequence sequence = ref.getSequence(refName);
iterator = reader.iterator();
Sam2CramRecordFactory factory = new Sam2CramRecordFactory(sequence.getBases());
factory.preserveReadNames = false;
factory.captureAllTags = false;
factory.captureUnmappedBases = true;
factory.captureUnmappedScores = true;
factory.preserveReadNames = true;