Subscriber Discussion

Camera To Monitor With Less Than .1 Second Delay?

UI
Undisclosed Integrator #1
Mar 16, 2017

I have a customer looking at a live feed camera (no recorder) to a monitor and requires less than a .1 second delay. My thought was to use an HD-TVI camera with a HDMI converter to achieve this, but I can't find a datasheet providing the specifics I've been looking for. If needed, cable runs would not exceed 70ft. 

1. Has anyone used one of these converters?

2. Is it in real-time, fitting the demands of this customer?

3. If not, has anyone utilized a different setup to achieve this type of result?

UM
Undisclosed Manufacturer #2
Mar 17, 2017

HD analog converter always can do the real time thing. And those degrade the picture quality only even the cable exceed the length limit.

Ml
Mendy lewis
Mar 17, 2017
Safezone24

HDTVI is good solution, I'm sure the delay is way less than 1 sec, but way convert the signal from camera, just use 4 port DVR with hdmi output

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UM
Undisclosed Manufacturer #2
Mar 17, 2017

OMG 1 second is way too long.... IP solution should be can be easily achieved in 300ms.

Avatar
Josh Hendricks
Mar 17, 2017
Milestone Systems

If I'm reading the post right, the requirement is 0.1 seconds or 100ms. Still achievable with IP i think, but maybe only using MJPEG.

The HDTVI route sounds good, and I wouldn't be surprised if it was cheaper to use a DVR vs using an adapter of some kind.

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JH
John Honovich
Mar 17, 2017
IPVM

Related: Testing IP Camera Latency, we were not able to get latency under 300-400ms.

UM
Undisclosed Manufacturer #2
Mar 17, 2017

John. You need an upgrade you network. :)

U
Undisclosed #3
Mar 17, 2017
IPVMU Certified

You need an upgrade your network. :)

You realize that the times you posted are within 300-400ms lower limit identified by John, right?

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UM
Undisclosed Manufacturer #2
Mar 20, 2017

Oh sorry. I didn't mention this screenshot is testing some EoC device(100M RG59) with some lousy switch.

UM
Undisclosed Manufacturer #2
Mar 20, 2017

Here's another test using cat5.

U
Undisclosed #3
Mar 20, 2017
IPVMU Certified

Let the IPVM record books be updated to reflect your time of 283ms :)

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UM
Undisclosed Manufacturer #2
Mar 20, 2017

I'm using some China network switch only. I think Cisco switch can beat this up to 250ms or lower. Any one try to test latency with better record?

Can this be even more to 100ms or maybe 50ms if well design and specific switch configuration?

U
Undisclosed #3
Mar 20, 2017
IPVMU Certified

Can this be even more to 100ms or maybe 50ms if well design and specific switch configuration?

Unlikely.  Switch latency is usually measured in micro-seconds, not milli-seconds.

Further, you seem to be overlooking the fact that the camera must encode the video into h.264 or mjpeg and then encode that into IP packets.  That is most likely the bulk of the remaining time.

UM
Undisclosed Manufacturer #2
Mar 21, 2017

Yes, μs at first but you need ms under heavy loading too, right ?
But it is true. I never saw any switch more then 10ms latency( If the manufacturer told us)
So you think latency mainly cause by camera itself in this case?
It sound logical but I don't know how to test it.

TC
Trisha (Chris' wife) Dearing
Mar 17, 2017
IPVMU Certified

...a different setup to achieve this type of result?

Apparently there are some monitors with direct TVI inputs:

Response time claimed is 5 ms (for monitor only). Could be just a built-in HDMI converter; still makes it a cleaner install.

That said, I've never seen one used or even read a review of any native HDA monitors besides small test ones.

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MB
Mark Bottomley
Mar 20, 2017

Don't forget there is a frame rate delay - the frame is sent only after captured and processed. e.g. 10fps means 100ms delay before any transmission, switching, decoding times.

Analog scans are real time, so should have little delay.

U
Undisclosed #3
Mar 20, 2017
IPVMU Certified

...10fps means 100ms delay before any transmission, switching, decoding times.

Disagree.  Although there is a 100ms gap between frames, the frame rate itself does not impact the latency between the capture time and the display time.

For instance, if you do the classic feedback latency test, as record holder distributor#2 did above, and changed the frame rate to 1 fps, you will get less frames of course, but the time differential on the frames you get will be the same.

If what you mean by latency is "the maximum possible delay before an event happening in view of the camera is actually depicted on the display", then its fair to say it could be up to an additional 100ms@10fps max, assuming the event occurs immediately after the last frame is captured.

To note, if the event is fast enough, it might not be captured at all, which is why this, IMHO, is a different concept than latency.

 

MB
Mark Bottomley
Mar 22, 2017

I agree with your "gap" description, although their is the exposure time that is part of the latency from the actual event to the display. A fast image capture leaves a long gap of unobservable actions, while a slow exposure using most of the frame time captures everything and usually blurs it. If the definition is only the network latency, then the FPS is irrelevant. I had a different interpretation of camera to display latency. Thanks for the correction.

Mark...

CH
Corbin Hambrick
Mar 20, 2017

sounds like a job for analog

 

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