Bitstream m_bitstream = new Bitstream(pis);
int streamPos = m_bitstream.header_pos();
aff_properties.put("mp3.header.pos", new Integer(streamPos));
Header m_header = m_bitstream.readFrame();
// nVersion = 0 => MPEG2-LSF (Including MPEG2.5), nVersion = 1 => MPEG1
nVersion = m_header.version();
if (nVersion == 2) aff_properties.put("mp3.version.mpeg", Float.toString(2.5f));
else aff_properties.put("mp3.version.mpeg", Integer.toString(2 - nVersion));
// nLayer = 1,2,3
nLayer = m_header.layer();
aff_properties.put("mp3.version.layer", Integer.toString(nLayer));