Attempting to write RTP stream to wave

Question

I have been working long and hard trying to figure out to save an RTP stream from a Cisco phone to a wave. I need the wave file to be in the format ULAW, 8khz, 8 bit mono.
Through much research this is the code I come up with but I does not work. I states that I am trying to get a datasink for null when I try to create the filewriter datasink.
I also have gotten the following error message with other version of the code below:
newReceiveStreamEvent exception Cannot find a DataSink for: com.sun.media.protocol.rtp.DataSource@3680c1
When I get the RTP stream I get the following as the format of the input stream:
- Recevied new RTP stream: ULAW/rtp, 8000.0 Hz, 8-bit, Mono
else if (evt instanceof NewReceiveStreamEvent) {
     try {
          stream = ((NewReceiveStreamEvent)evt).getReceiveStream();
Format formats[] = new Format[1];
formats[0] = new AudioFormat(AudioFormat.LINEAR,8000,8,1);
FileTypeDescriptor outputType = new FileTypeDescriptor(FileTypeDescriptor.WAVE);
DataSource ds = stream.getDataSource();
          // Find out the formats.
          RTPControl ctl = (RTPControl)ds.getControl("javax.media.rtp.RTPControl");
          if (ctl != null){
          System.err.println(" - Recevied new RTP stream: " + ctl.getFormat());
          } else
          System.err.println(" - Recevied new RTP stream");
          if (participant == null)
          System.err.println(" The sender of this stream had yet to be identified.");
          else {
          System.err.println(" The stream comes from: " + participant.getCNAME());
ProcessorModel processorModel = new ProcessorModel(ds, formats, null);
Processor processor = Manager.createRealizedProcessor(processorModel);
          processor.setContentDescriptor(new ContentDescriptor(ContentDescriptor.RAW_RTP));
MediaLocator f = new MediaLocator("file:/C:/output.wav");
DataSink filewriter = null;
DataSource tempds = processor.getDataOutput();
filewriter = Manager.createDataSink(tempds, f);
filewriter.open();
Edited by: phodat on Sep 16, 2010 10:17 PM
Edited by: phodat on Sep 16, 2010 10:20 PM

Answer 1

The content descriptor is designed to specify the output format, not the input format. The input format is specified by the DataSource automatically, and you set the content descriptor to whatever you want the output format to be. In this case, you'd want to set it to a WAV file.
You'd then need to go through all of the Track objects on the processor and set their output format to the ULAW specifications as you want there.
[http://www.cs.odu.edu/~cs778/spring04/lectures/jmfsolutions/examplesindex.html]
There's actually an example program that exports RTP streams, you can probably use that code without modification to fit your needs.