Not getting CDJ packets on Windows

[nzoschke]

Nice project. I've been playing around with this against a V10 mixer and CDJ-3000s.

On my Windows box it doesn't get any CDJ status packets.

It does discover devices, and gets what I believe is the mixer status packets but nothing from CDJs.

This project works out of the box on my Mac laptop. I also have a project with https://github.com/Deep-Symmetry/beat-link working properly on the Windows box.

Some hypotheses I've been investigating:

• Windows firewall
• Windows network device / address differences
• Announcement protocol / packets
• Timing differences

I'm opening this issue to put any further findings as I investigate.

[nzoschke]

I tracked down the error on Windows:

read udp [::]:50002: wsarecv: A message sent on a datagram socket was larger than the internal message buffer or some other network limit, or the buffer used to receive a datagram into was smaller than the datagram itself.

For some reason the status packet is length 1116 on Windows, so a change like this makes things work better:

func (sm *CDJStatusMonitor) activate(listenConn io.Reader) {
	packet := make([]byte, 2048)

Not sure why or any side effects yet but we're getting status!

[brunchboy]

CDJ-3000s have much larger status packets than other CDJs. I wonder why Windows can’t handle that?

[nzoschke]

The mystery is around the size of the buffer needed to handle the UDP read.

On Mac the read returns 512 bytes as expected for a CDJ status packet.

On Windows the read returns 1116 bytes.

So now I'm allocating a 2k buffer to read into which fixes the low level Windows error.

I haven't looked closely at the whole Windows packet yet since unpacking what was read into a Status struct is working the same way in both cases.

[brunchboy]

Strange indeed! Maybe you are getting multiple packets at once?

[evanpurkhiser]

Feel free to open a PR also :)