getCurrentPosition is not strictly monotonic while playing

Version

Media3 1.4.0

More version details

No response

Devices that reproduce the issue

Pixel 7 Pro (Android 14)

Devices that do not reproduce the issue

I assume none of them.

Reproducible in the demo app?

Not tested

Reproduction steps

I'm playing an MP4 audio while polling getCurrentPosition periodically to update the position, but I'm seeing some unexpected backward jump at around 3 seconds - the audio is playing fine - only the current position value seems wrong causing some unexpected UI glitches. It only seems to happen once, 3 seconds after playing started.

Confirmed using some debug traces:

position: 2.901s
position: 2.917s
position: 2.934s
position: 2.951s
position: 2.853s <--- here
position: 2.87s
position: 2.887s
position: 2.903s
position: 2.92s
position: 2.938s
position: 2.956s
position: 2.975s

Expected result

getCurrentPosition should be strictly monotonic during playing.

Actual result

getCurrentPosition randomly jumps backward.

Media

https://github.com/user-attachments/assets/65cf585e-a5b2-4920-966d-ac6b45a403fa

Bug Report

• You will email the zip file produced by adb bugreport to android-media-github@google.com after filing this issue.