MJSIP and codec interfacing

Question

Using Mjsip as the sip stack for my softphone project. There is class RtpSender.java has Method

public RtpSender(OutputStream output_stream, boolean do_sync, SIPCodec sipCodec, DatagramSocket src_socket, String dest_addr, int dest_port )
    {
        init( output_stream, do_sync, sipCodec, src_socket, dest_addr, dest_port );
    }

In another file AudioSender.java (this is a pure-java audio stream sender) I use that RtpSender method as follows...

sender=new RtpSender(audio_input_stream,true,**SIPCodec**,null,daddr,dport);

My problem is the SIPCodec, I have a interface named that for the codecs, what value I should pass r how should i pass? I am calling the codecids but it is showing method is not appropiate for this. Here is the codec interface...

public interface SIPCodec {
// Codec constants
public static String MEDIA_TYPE_AUDIO = "audio";
public static String MEDIA_TYPE_VIDEO = "video";
public static String ATTRIBUTE_PTIME = "ptime";
public static String ATTRIBUTE_RTPMAP = "rtpmap";
public static String ATTRIBUTE_FMTP = "fmtp";
public static String ATTRIBUTE_AS = "AS";
public static int DEFAULT_PACKETIZATION = 20;
public void encodeInit( int defaultEncodePacketization );
public void decodeInit( int defaultDecodePacketization );
...

And here is the codecs.java class from where I call the individual codecs.

public SIPCodec getSIPAudioCodec( int codecId ) {

        SIPCodec sipCodec;

        switch ( codecId ) {
            case audioCodecPCMU:
                sipCodec = new SIPCodecPCMU();
                break;
            case audioCodecPCMA:
                sipCodec = new SIPCodecPCMA();
                break;
            case audioCodecG729:
                sipCodec = new SIPCodecG729();
                break;
            case audioCodeciLBC:
                sipCodec = new SIPCodeciLBC();
                break;
            default:
                sipCodec = null;
        }