Feature: Customisable SAP announcement group address

[PheedbackPhil]

The group address for listening for SAP announcements apears to be hard coded to 239.255.255.255, whereas commonly used programs like FFMPEG and VLC use (I think) 224.2.127.254 - would be nice to have this configurable as this had me confused for a while!

[martim01]

I'd hardcoded it to what Dante in AES67 mode used. Hadn't occurred to me that other applications might use a different address. I'll make this configurable next time I make some changes

[PheedbackPhil]

Ah I wondered if it was something like that! Was very happy to see PAM being used in BBC CSq for audio monitoring, by the way!

[njh]

The different multicast addresses for SAP, depend on scope:

• Link-Local: 239.255.255.255
• Organisation: 239.195.255.255
• Global: 224.2.127.254

Many years ago, when I had a research network connection to Mbone, you used to be able to see Global SAP announcements from all over the (multicast) Internet.

However, I have seen SAP announcements from my Dante based AOIP44 appear in VLC (and been able to listen to the audio) - so I think VLC does support 239.255.255.255.

[PheedbackPhil]

You are absolutely right of course, @njh - I note that when I run VLC on my OSX box I see it listens on all three group addresses...

IPv4 Multicast Group Memberships
Group               	Link-layer Address	Netif
239.255.255.255     	1:0:5e:7f:ff:ff 	en0
239.195.255.255     	1:0:5e:43:ff:ff 	en0
224.2.127.254       	1:0:5e:2:7f:fe  	en0

I guess it would be nice for PAM to do the same perhaps?

[martim01]

Sounds sensible, and should be simple enough to do

[martim01]

I've altered the discovery panel to give the user the option to monitor local, organistation and/or global SAP rather than just local.
I'm currently not able to test that this works fully.