Sound is out of sync

How to fix audio and video sync issues with a Roku Streambar or Roku smart soundbar

When you watch a movie or TV show, or play a video game, the sound you hear and the picture you see is a combination of two elements – audio and video. Audio consists of spoken dialogue, music, and sound effects, while video is made up of a sequence of still images that when viewed in rapid succession form a moving picture. If you notice the sound from your Roku^® Streambar^® SE, Roku Streambar, Roku Streambar Pro, or Roku Smart Soundbar does not match the picture on your TV, you have likely encountered something called an audio/video synchronization error, or A/V sync error. One of the more apparent symptoms can occur when you see an actor speaking on screen and notice their lip movement does not match the words coming from their mouth. This type of A/V sync error is often referred to more precisely as a lip-sync error.

This article explains A/V sync errors in more detail and provides suggestions to correct the behavior.

What causes an A/V sync error?

An A/V sync error occurs when timing of audio and video is not synchronized. To understand why this happens, it is important to remember that audio and video are separate signals that are processed independently. With complex methods applied to varying amounts of data, processing of the two signals is often not completed at the same moment, leading to an intentional delay with either audio or video. While this is typically accounted for using timing information from both signals, there are other factors that can contribute to an A/V sync error, such as:

Poorly authored content: Audio and video are captured separately and must be synchronized before content is distributed. If not properly authored, a movie, TV show, or video game may contain incorrect timing information that leads to an A/V sync error.
Transmission error: Whether delivered over the internet, a coaxial cable or satellite dish, or on physical media (e.g., Blu-ray^™ disc, video game disc), all content must be transmitted to your devices. If data is lost or compromised during this process, incorrect timing information may be acquired when the audio and video signals are processed.
Content type: Although timing information typically accounts for this, higher resolution video signals such as 4K Ultra HD or HDR (High Dynamic Range) contain significantly more data taking longer to be processed for playback. As a result, the audio signal must be delayed longer after it is processed. If this does not occur, an A/V sync error may result.
TV settings: Picture settings that affect video processing, or sound settings that convert one audio format to another (also known as audio transcoding) may introduce an A/V sync error or exaggerate one that already exists.

How do I fix an A/V sync error?

If you notice an A/V sync error when using your Streambar or soundbar with your TV and/or connected devices (e.g., game console, Blu-ray player, cable/satellite set-top box), read through the questions below to help narrow the problem.

Are all titles on a channel or device affected?When you encounter an A/V sync error, stop playback of the movie or TV show and try a different title. If you are playing a video game when you encounter an A/V sync error, try another title on the same game console. If you determine that the sync error is isolated to a single title, it is likely that the movie, TV show, or video game is poorly authored or damaged. With streaming content or content from your cable/satellite provider, try watching the movie or TV show on another channel. With physical media, try cleaning the disc or replacing it with an alternate copy.
If the A/V sync error affects multiple titles, continue to the next step.

Are all devices affected?If multiple titles are affected, switch your TV to a different device (from the one where the A/V sync error was discovered) and play a movie, TV show, or video game on the new device. If you discover that the sync error only occurs on the original device, try restarting that device.

If the A/V sync error occurs with multiple titles on a single streaming channel, close the channel and try watching content on another streaming channel. If the A/V sync error goes away, re-launch the original streaming channel and resume playback of the same titles to determine if the sync error was an isolated event. If multiple titles are still affected only on the one streaming channel, contact the service provider to report the issue.

If the A/V sync error affects all devices, continue to the next step.

Try adjusting TV settingsTry adjusting the TV settings described below to help fix an A/V sync error. Consult online documentation for your TV model or contact the manufacturer directly for detailed instructions.

- Some TV models have an A/V Sync feature that can often be found in an Audio sub-menu within the Settings menu on your TV. If the feature exists on your TV, try adjusting it to see if A/V sync improves. The feature may also be called something like Audio delay or Lip-sync.
- Use the following suggestion if sound is distinctly heard before you see the picture.
  - Turn off any advanced video processing on your TV such as motion smoothing, or video noise reduction. These controls are often found in a Video or Picture Settings sub-menu within the Settings menu on your TV.
- Try the suggestions below if sound is distinctly heard after you see the picture.
  - Set the digital audio output on your TV to PCM. You can often find this setting in an Audio sub-menu within the Settings menu on your TV.
  - Try turning off Game Mode if the setting exists on your TV.