Dr. Spankenstein

How should I encode data so that it can be recognized in Max without errors such as:

udpreceive: OSC packet size (30) not a multiple of 4 bytes: dropping

I am current encrypting a simple string message as follows [C#]:

            string tempMessage = "Hello Max/MSP";
            data = Encoding.ASCII.GetBytes(tempMessage);


The data variable is then sent to port 7400 where it is received by Max but then rejected as it is not a multiple of 4 bytes.

How can I rectify this problem, do I need some extra padding to make the message up to a multiple of 4 bytes, or is there something else that is missing, perhaps a different method of encoding?

using-the-udpreceive-object-with-outside-code-c

You could try creating an array of characters 

that is 32-bit aligned and see if it is accepted.

You could try creating an array of characters 
that is 32-bit aligned and see if it is accepted.


I have tried padding the message so that it is a multiple of 4 using the following code [C#]:

        private byte[] PadMessage(string message)
        {
            byte zero = 0;

            // Clear current list of bytes
            bytes.Clear();

            // Add the encoded message as bytes
            bytes.AddRange(encoding.GetBytes(message));

            // Pad the message so that its length is a multiple of 4
            int padding = 4 - (bytes.Count % 4);
            for (int i = 0; i < padding; i++)
            {
                bytes.Add(zero);
            }

            return bytes.ToArray();
        }


The data is sent to Max and I now receive the following error:

udpreceive: OSC expected type string. Dropping message for address Hello Max/MSP

The string needs to encoded as bytes to be sent via UDP so why am I getting this error in Max?

in the past, i've used oscpack to send data to max over udp, from a c++ app. 

http://www.audiomulch.com/~rossb/code/oscpack/

however, it's implementation just uses the os send function, which takes a char * as the data to send.

in the past, i've used oscpack to send data to max over udp, from a c++ app. http://www.audiomulch.com/~rossb/code/oscpack/

Figured out a solution to using third-party apps with udpreceive ...

In Flash / AS3 I did the following (retyped so there could be typos):

for ( var i:int = 0; i < pad; i++ ) { data.writeByte(0); }

datagramSocket.send( data, 0, 0, targetIP, targetPort);

var message:String = "Hello!";
var data:ByteArray = new ByteArray();
data.writeUTFBytes(message);
var pad:int = 4 - ( data.length % 4 );
for ( var i:int = 0; i < pad; i++ ) { data.writeByte(0); }
data.writeUTFBytes(",");
data.writeByte(0);
data.writeByte(0);
data.writeByte(0);
datagramSocket.send( data, 0, 0, targetIP, targetPort);


Using the UDPRECEIVE object with outside code [C#]