Subscriber Discussion

HD-SDI Hdcctv Frame Rate / Latency / Jitter

I found this interesting video that shows a side-by-side comparison of an unnamed HD-SDI and IP Camera setup. I think the IP disadvantages are exaggerated a bit, but was still interesting to watch. In my IP setup at 15 FPS I sometimes get uneven frame rates (never the huge gaps this youtube video shows). I also notice if 2 cameras are watching the same area there is a lag between the two cameras, they don't sync perfectly. The video suggests the HD-SDI doesn't have either of these issues. At 1-8 FPS these IP issues are not noticeable.

The HD SDI / HDcctv Tutorial does a good job of explaining the differences.

We routinely see similar effects where IP cameras can be slightly out of sync. Fundamentally, with IP, you have an encoder for every camera, whereas with analog or HD SDI, it's on encoder per group of cameras.

Btw, this post on time synchronization might be of interest to this topic.

Those look like streams from the same camera, and the 'ill IP' effects appear to just be edits.

  • Notice the IP time starts at the same, but finishes before the HD-SDI time?
  • And both cameras are labeled 'camera 4'
  • And both cameras have the same (Chinese?) description labels

Summary: it's a fake comparison.

Even if it's fake, I am sure you can replicate this with a cheap enough IP camera on a poor enough network. That said, jitter at the level portrayed is extremely uncommon.

And of course most people aren't watching video live, and even those that ARE watching live video aren't using it for remote robotic surgery.

The latency, or lack thereof, of live video isn't a selling point for most common applications (I realize that casinos are one exception case).

The recorded video with HD-SDI (or derived) systems is going to be h.264, so it's not going to be the same as what you're seeing live, and will be mostly indistinguishable from a comparably configured IP camera system.