Why is there audio lag with Bluetooth Earbuds in Windows 10?
Bluetooth headphones always have additional latency because of encoding, transmission, buffering and decoding of the audio stream. The latencies I have seen have varied from 30 ms to nearly a second. Some video players are able to correct for latency, but not all. An additional problem is that while Bluetooth headphones are supposed to report their latency to the computer or phone to allow latency correction, some headphones either report wrong number or nothing at all. This problem is most often found in cheap headphones like Xiaomi, but some name brands do it too. For these, synchronizing audio and video is impossible without separate calibration.
Edit: According to OP's self-answer, disabling audio "enhancement" fixed the problem, and "enhanced" audio syncs correctly when played from built in speaker. The most probable explanation is that both the headset and "enhancement" have correct latency compensation, but when "enhancement" is used, the latency from Bluetooth is not used in synchronization. This is a bug in the audio driver.
You may have Audio Enhancements enabled. This causes a delay in the sound (in addition to the delay already present from Bluetooth headphones).
To disable this feature:
- Right Click the speaker icon next to your clock calendar at the bottom right of your desktop
- Select Troubleshoot sound problems
- Select your audio device, it should be listed as Haylou-GT2_R and includes (Current Default Device) in the description, click next
- Select Yes, Open Audio Enhancements
- In the Enhancements tab, checkmark Disable all enhancements
- Select OK
Your sound will cut out for 1 second and come back without lag