[Double-A]

Hello there Head-Fiers!,

I was curious if there have been any studies conducted to determine how much latency a bluetooth connection must have before the average person will notice a lag. Unsynchronized lip movement during dialogue in movies being an example.

Have any studies of this sort been conducted?

Thank you,
Alec

 

[bfreedma]

The full paper requires a subscription, but the abstract provides an overview:

”The results of the experiment determined that the average audio leading threshold for a/v sync detection was 185.19 ms, with a standard deviation of 42.32 ms”

https://ieeexplore.ieee.org/document/4599253

 

[castleofargh]

For fun, there are several video players that allow to input a delay to the audio track. You can play with that and make your own opinion, or you could do the same in a video editor app.
The massive caveat is that a TV/monitor can also have some pretty significant lag for the video, which in the case of BT rigs could be a blessing I guess. Anyway it's not nearly accurate as a testing method, but it gives a sense of the magnitudes needed IMO. In my case, I rapidly realized that anything below 100ms wasn't going to bother me. Which is fun given how paranoid I was in my gamer years about anything as "huge" as 100ms or 125ms. Different circumstances have different actual needs, and in this case, I only learned that after playing with the audio delay myself.

Didn't the latest versions of BT have something about audio and video sync? I think I read something like that. It would be pretty interesting if that synchronization could adjust itself dynamically to our listening conditions. Because that's personally what pisses me off with BT. Not that there is a delay, but that the delay can change so massively depending on how we use the gear.
Then I guess the 50ms or more of some super laggy screens would become technically bad again.^_^

 

[bigshot]

With film, I can barely discern a 1 frame shift (1/24th of a second). I can't tell you if it is early or late with that small a shift though. Most people can discern 2 to 3 frames out of sync (1/12 to 1/8th of a second). It depends a lot on the visuals though.