long globalRecordCounter, SubstitutionMatrix substitutionMatrix,
boolean AP_delta) throws IllegalArgumentException,
IllegalAccessException, IOException {
// get stats, create compression header and slices
long time1 = System.nanoTime();
CompressionHeader h = new CompressionHeaderFactory().build(records,
substitutionMatrix);
h.AP_seriesDelta = AP_delta;
long time2 = System.nanoTime();
h.readNamesIncluded = preserveReadNames;