Symptoms
- Dialogue lags behind lip movement using TV speakers only
- Delay appears mainly on one streaming app
- Live TV or cable box has correct sync
- Delay changes after a software update
Likely causes
- CommonPicture processing mode adding video delayMotion smoothing and other enhancement features can slow the video frame relative to audio.
- CommonStreaming app buffering or decoding audio and video separatelySome apps are known to have sync bugs independent of the TV hardware.
- PossibleOutdated TV softwareBugs in older firmware versions can affect audio/video timing.
- PossibleHDMI cable or source device issueAn external device connected via HDMI can introduce its own processing delay.
- Less commonTV audio hardware faultA failing internal audio processor could cause persistent, uncorrectable delay.
What to do
- Turn off motion smoothing, game mode toggle, or other picture enhancement features in the TV's picture settings.
- Check if the delay happens on live TV/cable as well as streaming apps to narrow down if it's app-specific.
- Update the TV's software to the latest version through its settings menu.
- Restart the streaming app or try a different app to see if the delay is isolated to one source.
- If using an external device (game console, streaming box), test a different HDMI port and cable.
- Restart the TV completely by unplugging it for a minute.
When to call a pro
If the delay is consistent across all sources including live TV and persists after updates, contact the TV manufacturer's support for a hardware evaluation.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.