Blackmagic Forum

I noticed that the output of 2110 supports synchronization with PTP.

At the same time, I used Riedel NMOS Explorer software to view the SDP and confirmed this.

Code: Select all

v=0
o=- 2163100547 2 IN IP4 192.168.0.80
s=SDI 1
t=0 0
a=sendonly
m=video 16388 RTP/AVP 96
c=IN IP4 239.255.66.205/255
a=rtpmap:96 raw/90000
a=fmtp:96 sampling=YCbCr-4:2:2; depth=10; width=1920; height=1080; exactframerate=60; colorimetry=BT709; PM=2110GPM; SSN=ST2110-20:2017; TP=2110TPN;
a=ts-refclk:ptp=IEEE1588-2008:00-09-0D-FF-FE-01-26-6C:127
a=mediaclk:direct=0
a=ssrc:3117230440 cname:DCB387D49C894869810C417119E6BB95


But I use QXL for analysis and it doesn't seem to sync.

Hello,

I have a similar issue.
In follower mode, the 3x3 IP Converter does not synchronize to my PTP GM...
It would be good, as PTP is a crucial point, to have more debug and possibilities to fine tune...
Actually I have an Ultrix IPX-IO card, Phabrix QX and some emSFP which are correctly working, including NMOS, on our network. We are using a Netgear SMPTE 2110 compliant switch and a Meinberg microSync PTP GM.

Riddle me this:
Why do these units output 3 x 64 channels of audio RTP when SDI can only handle 16 channels?

a=rtpmap:97 L24/48000/64 (48000 Hz, 64 channels, s32 (24 bit), 73728 kbit/s)

Fine question.

The device is a SMPTE 2110 group of standards device. SMPTE 2110 has 64 “undefined audio groups”. That would be (3) SDI lines times 64 “undefined audio groups”.

I’m assuming that’s the answer. Someone else does audio channel grouping so that's not on my list of worries thankfully. I just sit backstage and press the shiny buttons.

That was confusing to read about on an SDI box.

That does stink that that device won't instantly sync up. It's designed to.

So IEEE Standards Association describes IEEE 1588 as the protocol that enables heterogeneous systems that include clocks of various inherent precision, resolution, and stability to synchronize to a grandmaster clock.

According to SMPTE, SMPTE 2059, used in SMPTE 2110 system of standards used on the Blackmagic device, is an integral part of emerging professional IP video broadcast technology and standards.



The Blackmagic 2110 device lists using 3 Precision Time Protocols
IEEE 1588-2008 (PTP v2)

SMPTE 2059-1 – Defines signal generation based on time information delivered by the IEEE 1588 protocol.

SMPTE 2059-1 – Defines signal generation based on time information delivered by the IEEE 1588 protocol.


I’m just a camera director, but there are variable in hardware versus software derived PTP. Not sure which is used here or if it matters if there is an auto setting in follow mode based on feedback from a network maybe?

Say for example, The System Clock is at 9:00:00. The Second Device keeps track of the offset time between the system and itself. The Second device clock thinks it’s 9:00:10, so we have a 10-second offset. To keep it simple, we’ll imagine we have a one-second delay to transfer packets from the System Clock to the Second Device clock.

The System Clock periodically sends a sync message. Let’s say it sends a sync message at exactly 09:00:00. This moment is the T1 value. We now have two options:
• If your hardware supports PTP:
o The exchange is called a one-step message exchange, and we only send a sync message that contains the T1 value.

• If however, PTP is done in software:
o PTP uses a two-step message exchange because of additional delays.
o This means that after the sync message, we send a follow-up message immediately, including the T1 value.
o The T1 value won’t be in the sync message.
o The follow-up message means, “The sync message you just received was sent at the time specified in the T1 value”.


With so much going on behind the scenes, it would be great to see a list of tested network devices, menu profiles, and cabling for the 2110 IP Converter 3X3G. What are we missing here?

It does still look like a great device for live events even if it’s not timed to your existing IP network down to the sub-microsecond. It saves on cable runs and the format is designed as a low-latency system for production facilities.

Is there a setting in any of these Blackmagic ST2110 devices to choose ST 2059-2 as it's Time Code choice? It is listed as one of the Precision Time Protocol options on all of the devices.

SMPTE is listing ST 2059-2 as an operating profile for the IEEE protocol optimized to the needs of media synchronization.

Also is there a VITC choice? That would be what we are sending to the switcher from the device in order to sync our system with the network clock.

Sorry, I listed the second protocol twice in my first message. I'm listing stuff people already know just because I'm learning here and maybe someone can tell me when I'm getting it wrong or if I'm close to it.

The control protocols listed for these ST2110 devices are:
Precision Time Protocol: IEEE 1588-2008 (PTP v2), ST 2059-1, ST 2059-2

Someone try ST 2059-2 if there's an option

If you have an option, choose VITC timecode for SDI