public static Map getCodec(SessionDescriptor offers) {
Logger logger = Logger.getLogger(Codecs.class.getCanonicalName());
if (offers == null) {
logger.warning("offers == null");
return null;
}
MediaDescriptor mAudio = offers.getMediaDescriptor("audio");
if (mAudio == null) {
logger.warning("offer doesn't contain m=audio");
logger.info(offers.toString());
return null;
}
MediaField m = mAudio.getMedia();
if (m == null) {
logger.warning("media field invalid");
return null;
}
String proto = m.getTransport();
// see http://tools.ietf.org/html/rfc4566#page-22, paragraph 5.14, <fmt> description
if (proto.equals("RTP/AVP") || proto.equals("RTP/SAVP") || proto.equals("RTP/SAVPF")) {
Vector<String> formats = m.getFormatList();
Vector<String> names = new Vector<String>(formats.size());
Vector<Integer> numbers = new Vector<Integer>(formats.size());
Vector<Codec> codecmap = new Vector<Codec>(formats.size());
// add all avail formats with empty names
for (String fmt : formats) {
try {
int number = Integer.parseInt(fmt);
numbers.add(number);
names.add("");
codecmap.add(null);
} catch (NumberFormatException e) {
// continue ... remote sent bogus rtp setting
}
}
;
logger.info("got " + numbers.size() + " format numbers");
// if we have attrs for format -> set name
Vector<AttributeField> attrs = offers.getMediaDescriptor("audio").getAttributes("rtpmap");
logger.info("got " + attrs.size() + " rtpmap attributes");
for (AttributeField a : attrs) {
String s = a.getValue();
// skip over "rtpmap:"
s = s.substring(7, s.indexOf("/"));
int i = s.indexOf(" ");
try {
String name = s.substring(i + 1);
int number = Integer.parseInt(s.substring(0, i));
int index = numbers.indexOf(number);
logger.info("format offered " + index + ", " + name);
if (index >= 0) names.set(index, name.toLowerCase());
} catch (NumberFormatException e) {
// continue ... remote sent bogus rtp setting
}
}
Codec codec = null;
int index = formats.size() + 1;
logger.info("number of local codecs = " + codecs.size());
for (Codec c : codecs) {
logger.info("checking " + c.userName() + ", valid = " + c.isValid());
if (!c.isValid()) continue;
// search current codec in offers by name
int i = names.indexOf(c.userName().toLowerCase());
if (i >= 0) {
logger.info("adding codec " + c.userName() + " by name");
codecmap.set(i, c);
if ((codec == null) || (i < index)) {
codec = c;
index = i;
continue;
}
}
// search current codec in offers by number
i = numbers.indexOf(c.number());
if (i >= 0) {
if (names.elementAt(i).equals("")) {
logger.info("adding codec " + c.userName() + " by number");
codecmap.set(i, c);
if ((codec == null) || (i < index)) {
// fmt number has no attr with name
codec = c;
index = i;
continue;
}
}
}
}
if (codec != null) return new Map(numbers.elementAt(index), codec, numbers, codecmap);
else {
// no codec found ... we can't talk
logger.warning("didn't find any recognised codec");
return null;
}
} else {
/*formats of other protocols not supported yet*/
logger.warning("can't handle protocol: " + proto);
return null;
}
}
