Unexpected long delays in tf.nextFrame() inside observe loop

[Smruti-AT]

I’m seeing unexpected and occasionally very large delays when calling await this.ml.human.tf.nextFrame() inside an observe loop which runs for 5 minutes.

What I’m doing
Inside a continuously running observe loop, I call:
await this.ml.human.tf.nextFrame(); I log a timestamp immediately before and after this line to measure how long the await takes.

Observed behavior
In most iterations, the time difference between the two timestamps is ~1 second, which is expected.
However, intermittently I observe much larger delays:

• One iteration had a delay of 13 seconds
• Another iteration had a delay of approximately 198 seconds
• These long pauses appear sporadically and are not correlated with any explicit blocking code on my side.

Environment

• "@vladmandic/human": "^3.3.2"
• @tensorflow/tfjs: ^4.20.0
• @tensorflow-models/body-segmentation: ^1.0.2
• Running inside an observe loop (browser environment)

Question
Is there a known reason why tf.nextFrame() might occasionally block for such long durations (e.g., event loop starvation, GC pauses, internal TFJS scheduling, or browser throttling)?
Any guidance on diagnosing or mitigating this behavior would be greatly appreciated.

[vladmandic]

Is there a known reason why tf.nextFrame() might occasionally block for such long durations (e.g., event loop starvation, GC pauses, internal TFJS scheduling, or browser throttling)?

i'm not aware of any such issue.
browser throttling happens when you navigate away fom the page. while page is in focus, it should not happen.
event loop starvation is not something i've seen in modern browsers.
what else is possible is even gpu sync causing a temp lockup, but that would heavily depend on gpu model and gpu drivers used.

you can try analyzing browser profiler, but it can be a lot.

[Smruti-AT]

Thank you for the response. The throttling was indeed due to switching of tabs. Is there any way to have the consistent nextFrame() behaviour even while the tab is out of focus?

[vladmandic]

it's fully up to browser and outside of app control