Live TV delay through Tablo

I’ve always been curious by how much live TV is delayed from realtime while watching on Tablo. On news programs, where they show a realtime clock, I can note the difference between exact time and what I see on the screen’s clock, but that doesn’t tell me anything about the delay I’d see if watching live TV via the TV’s tuner.

So this morning, I set up a test to get an approximate measurement on the 2 delays. This wasn’t a scientific test where I started and stopped Tablo a number of times over a number of channels, rather, just a one time measurement. I should note my Tablo is hardwired to my router, I was watching on a Roku stick with an “excellent” 5GHz signal, and fast startup on Tablo enabled. The watch I used to measure delay from realtime is a Citizen Navihawk AT (Atomic Time) which updated overnight, and is very accurate.

Anyway, for live TV coming in via the TV’s tuner, I measured 9 a second delay, while on the Tablo, I measured 23 seconds, giving me a delay through the Tablo of 14 seconds. It would be interesting to see how repeatable this is over multiple tests on multiple channels, and also to see what the delay is if fast TV startup is not enabled.

The technical reasons behind the delays have been well documented a gazillion times (for the non-tech crowd). I did create this video which show the delay and other features of the Tablo using latest software.

You’re also assuming the station’s real-time clock is accurate. :wink:

They usually are, or used to be. But it was only a reference point so I could measure Tablo’s delay. I’ve been wondering, tho, if the live TV delay I saw through the TV’s tuner was due to an error in their clock, or is a byproduct of digital transmission process. Back in the days of analog transmissions, the delay, if any, wasn’t really noticeable.