Composite video???

With HDMI, and a decent camera and a monitor chosen for the purpose, I strongly suspect that it's possible to get delay of no more than 3 frames, maybe 4. That's .1 second or so, which is at the limit of perception of most untrained observers.

https://www.pubnub.com/blog/how-fast-is-realtime-human-perception-and-technology/

The only way you'll see something less than 3-4 frames (30ms per frame or so) is if you have 2 monitors *of different delays* next to one another, and you watch for cuts; it won't be perceptible in dissolves either.
 
I guess what I am sayingt right now is that in the analog video world, we had incremental improvements until we reached the technical ceiling so to speak. But each part of the path forward didn’t come with as much sticker shock. To move from a 100 buck analog no latency director cam to digital is not a few bucks more, but rather an order of magnitude. Fine if you want to be an “Early adopter” or if you really want/need the increased video resolution. For me the matrix of price, latency, and quality.. is still a “pick any two” situation. Especially if it’s a function that does not impact what the audience sees or hears.

We have been making incremental improvements in digital as well. Problem is, most people weren't aware of the early bits. It was too expensive and analog was still an option. With the analog sunset in consumer gear, many people who wanted to not move forward are starting to have their hand forced. The cost of digital gear has plummeted as a result. However, with that, there is a much greater gap in quality.

My best advice for anyone who is moving to digital is to get the display with the fewest type of inputs, preferably one type of input. Ideally, if you can go with SDI all the way (camera, distribution, monitor), then you will have the best results. Every piece of gear that has the possibility of processing the signal will add latency. SDI, created for the broadcast industry, may add some additional cost to your purchase as it was never intended for consumer equipment. Another option is HDBase-T, which is designed for consumer gear. It has dramatically increased in availability and dropped in price over the past few years. Again, if you have the camera, distribution, and monitor that are all using that protocol, then it has essentially no latency.

As I said before, composite is not dead. It may become increasingly more difficult to support, but it isn't dead. It is still the right method of distribution for some situations.
 
Composite video is not 'dead' but you're only going to find it on small security/lipstick cameras and maybe some low-end consumer 'toy' cameras and you'll still want either a professional monitor or a CRT (ideally a professional CRT) to display as real-time as possible. It's definitely harder to find what you need for a real-time composite feed than it used to.

SDI (and HDSDI and 3GSDI and ...) is true realtime and the signaling format is backwards compatible*. If you get a professional (3G/HD)SDI camera and feed it into a professional (3G/HD)SDI display then the only delay you should have is the capture and display time delay - there shouldn't be any buffers in the way and the image is 'scanned' down the cable just as it was for a CRT with a flyback. Note that a CCD capture device does not scan sequentially so there may be some added minor delay here so you would probably want a CMOS imager and most LCDs display what is essentially whole-image at once so you may have some minor delay here but those delays even if you have them should add up to at most 2 frames (1/15 of a second) - the better you configure your system, the lower that delay. If you want to talk standards and details (SAV/EAV/color encoding/etc.), let me know.
Oh, and I don't feel like I'm old enough to be an "old timer" but I can wax philosophically about NTSC, NTSC-II, NTSC-III, System B/G/I/K/..., PAL, SECAM, et al. all day long.


* seriously, us TV folks keep making sure everything works in lock-step with the previous generation so in theory you could take a 12GSDI dual link 4K signal and generate a NTSC black and white [not NTSC-II or NTSC-III color] signal in realtime and the most delay would be less than a front porch, likely less than a color subcarrier wave or two - if someone has made the hardware to do this is a different question.
 
Remember when Chyron, Vidifont, and other CG (thats Character Generators, you yutes) systems relative quality was measured in waveform rise-times.

27ns and so on. I think the 4100s got down to like 15ns.

Yup, I was sittin' on the front porch admiring the burst of subcarrier shrubs...

:)
 
Composite video is not 'dead' but you're only going to find it on small security/lipstick cameras and maybe some low-end consumer 'toy' cameras and you'll still want either a professional monitor or a CRT (ideally a professional CRT) to display as real-time as possible. It's definitely harder to find what you need for a real-time composite feed than it used to.

SDI (and HDSDI and 3GSDI and ...) is true realtime and the signaling format is backwards compatible*. If you get a professional (3G/HD)SDI camera and feed it into a professional (3G/HD)SDI display then the only delay you should have is the capture and display time delay - there shouldn't be any buffers in the way and the image is 'scanned' down the cable just as it was for a CRT with a flyback. Note that a CCD capture device does not scan sequentially so there may be some added minor delay here so you would probably want a CMOS imager and most LCDs display what is essentially whole-image at once so you may have some minor delay here but those delays even if you have them should add up to at most 2 frames (1/15 of a second) - the better you configure your system, the lower that delay. If you want to talk standards and details (SAV/EAV/color encoding/etc.), let me know.
Oh, and I don't feel like I'm old enough to be an "old timer" but I can wax philosophically about NTSC, NTSC-II, NTSC-III, System B/G/I/K/..., PAL, SECAM, et al. all day long.


* seriously, us TV folks keep making sure everything works in lock-step with the previous generation so in theory you could take a 12GSDI dual link 4K signal and generate a NTSC black and white [not NTSC-II or NTSC-III color] signal in realtime and the most delay would be less than a front porch, likely less than a color subcarrier wave or two - if someone has made the hardware to do this is a different question.
@eadler Would you mind 'philosophically waxing' a few frames from a couple of RCA's 2" Helical cartridge shuffling decks; these were practically from the steam age and somewhat 'Rube Goldberg' like when a pair were steaming their way through a top of the hour commercial break with a station ID and a couple of PSA's tossed in for extra credits.
Toodleoo!
Ron Hebbard
 
(If i may slightly de-rail the initial subject of this thread while we're on the topic of video latency)

What's up with NDI? The barebones theoretical latency is tiny, yet whenever I've tried using it over a 10Gb/s connection between two machines, it always seems to be in the 100s of milliseconds...
 
(If i may slightly de-rail the initial subject of this thread while we're on the topic of video latency)

What's up with NDI? The barebones theoretical latency is tiny, yet whenever I've tried using it over a 10Gb/s connection between two machines, it always seems to be in the 100s of milliseconds...
I wish that I could speak to that, but I haven't had a chance to play with any NDI signal paths as of yet. Have you checked with NewTek?
 
Just started messing around with NDI. Tried to do something simple at the church.
Created an NDI network stream of live video for people on campus to view by installing the NDI VLC plugin.
So far, couldn't get it to work.
Has anyone used NDI successfully? They make it seem so easy
 

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