Having latency challenges with NDI and NC1IO (and spanks) on TC1

Dave G

New member
Just wondering what we should be expecting in terms of latency, getting in the neighborhood of 1/4 second vs the near instant inputs on the back of our TC1 and 460.

Everything is going through a generic unmanaged 16 port ethernet switch.

The NC1 and the TC1 are showing up as gig ethernet connections to the switch, but the sparks only show a link of 100Mbps, though everything seems full quality and clean when the audio and video is coming through, but the latency is a killer for multicam when we're trying to cut sports.

Any ideas on tracking this down?
 

kanep

NewTek SE
The Spark HDMI and Spark SDI unit have 100Mb Ethernet ports. The NC1IO should be just fast as well, while technically a frame slower than the on board SDI, I wouldn't think would be able to see it.

The Spark HDMI/SDI units are using NDI-HX, the LongGop compression of this format will have some latency.
 

JPulera

New member
Could you use the Video Delay function on SDI inputs to allow NDI sources to catch up? Audio can also be delayed of course, so you ought to be able to get it all pretty much dialed in. Not good for iMag of course to ADD latency, but should be okay for recording, streaming, broadcast.

Thanks

Jeff
 

prometeus

New member
Just wondering what we should be expecting in terms of latency, getting in the neighborhood of 1/4 second vs the near instant inputs on the back of our TC1 and 460.

Everything is going through a generic unmanaged 16 port ethernet switch.

The NC1 and the TC1 are showing up as gig ethernet connections to the switch, but the sparks only show a link of 100Mbps, though everything seems full quality and clean when the audio and video is coming through, but the latency is a killer for multicam when we're trying to cut sports.

Any ideas on tracking this down?

Hi we are facing the same problems with the 2 NC1 I/O units a switch (HP1910 8g or our customer’s cisco nexus 93108) and VMC1 unit.
For example in the following chain
Camera SDI out –NC1I/0 ->switch->VMC1->( SDI Monitor)
we measure 5 frames of delay with genlock active on Nc1 and genlocked sources with frame sync disabled on all input tabs on vmc1.
Note that we cannot detect a better delay if we remove genlock from NC1 unit. This is very strange.
We are a little bit worried cause reading your ndi documentation it takes 1.5 frame for processing baseband video signal from sdi in to out when genlock is active and properly set. Also the ndi encoding should take 1 frame or less
So we really don't understand the nature of this delay.
Things get even worse if we add to the chain another NC1 unit : indeed the total delay raises to 8 frames with an hp switch (even ten if use a cisco 93108 switch....but I'm using a simple hp switch with a default config ...IGMP enabled and nothig seems to fight with Mdns or ephemeral ports or UDP ports running from 5960 on).
Someone could help me with this?
 

tominmelb

New member
Hi we are facing the same problems with the 2 NC1 I/O units a switch (HP1910 8g or our customer’s cisco nexus 93108) and VMC1 unit.
For example in the following chain
Camera SDI out –NC1I/0 ->switch->VMC1->( SDI Monitor)
we measure 5 frames of delay with genlock active on Nc1 and genlocked sources with frame sync disabled on all input tabs on vmc1.
Note that we cannot detect a better delay if we remove genlock from NC1 unit. This is very strange.
We are a little bit worried cause reading your ndi documentation it takes 1.5 frame for processing baseband video signal from sdi in to out when genlock is active and properly set. Also the ndi encoding should take 1 frame or less
So we really don't understand the nature of this delay.
Things get even worse if we add to the chain another NC1 unit : indeed the total delay raises to 8 frames with an hp switch (even ten if use a cisco 93108 switch....but I'm using a simple hp switch with a default config ...IGMP enabled and nothig seems to fight with Mdns or ephemeral ports or UDP ports running from 5960 on).
Someone could help me with this?

Hey Prometeus, did you ever work out was was causing the extra latency? 1-1.5 frames in the minimum latency of VMC1, perhaps having DSK enabled etc increases latency?

Cheers
TD
 

jonberg

Member
I've experienced that EVERY conversion takes minimum 1,5 frames

NCI/O --------------------------> TC1
SDI IN -> NDI ----> NDI -> Processing -> SDI
_____ 1,5 ____ + ____ 1,5 ___ + ___ 1,5 ___ = 4,5 frames

=> so maybe there you have the 5 frames delay
 
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