Audio and video out of sync? How to fix lip-sync problems on TV and streaming

Lip-sync errors, where audio is out of sync and voices arrive before or after mouths move, are surprisingly common. Viewers often notice a gap of a small fraction of a second. The cause is usually processing delay: the TV, soundbar or receiver takes different amounts of time to handle picture and sound. Here's how to track it down.

Why audio goes out of sync in the first place

Picture and sound take different paths through your equipment, and each step adds a little delay:

• The TV processes the picture: scaling, motion smoothing, noise reduction, HDR tone mapping. Heavy processing adds delay to the video.
• The soundbar or receiver decodes and processes audio: surround formats, room correction, virtual surround effects. That adds delay to the sound.
• The connection between them, especially ARC and eARC, involves the TV passing audio onward, which adds its own small delay.
• Wireless audio, such as Bluetooth headphones or wireless rear speakers, adds further delay.

When these delays don't match, lips and voices drift apart. Most equipment tries to compensate automatically, but automatic compensation relies on devices reporting their delays accurately to each other, which doesn't always happen.

How much delay is noticeable?

People are generally more tolerant of sound arriving slightly late than early, because in everyday life sound travels more slowly than light. Even so, a delay of a small fraction of a second can be distracting, particularly in close-up dialogue. Adjust until speech looks natural to you rather than aiming for a particular number.

A quick test you can do at home

Before changing settings, choose a reliable reference:

• A news presenter or interview, where faces are clearly visible
• A video with a clap or a clapperboard, where sound and picture should align exactly

Watch the reference on your normal setup, then on the TV's built-in speakers. If it looks right on the TV speakers but wrong through the soundbar, the problem lies between the TV and the audio equipment. If it's wrong on both, look at the source, the streaming device or the TV's picture processing.

Step 1: Narrow it down

• One channel or program only? The problem is probably in the source broadcast or stream. Change channel and back, or restart the app. If it persists, report it to the provider.
• One app only? Update or reinstall the app, and check its own audio settings. If it also crashes or freezes, see fixing streaming apps on smart TVs.
• Everything, on a soundbar or receiver? It's almost certainly a delay between your TV and audio equipment. Go to Step 2.
• Everything, on TV speakers? Check the TV's picture processing settings. Go to Step 3.

Step 2: Fix soundbar and receiver delay

When sound goes through a soundbar or AV receiver, especially via ARC or eARC, the TV and audio device need to agree on timing.

1. Turn on automatic lip-sync if available. HDMI devices can report their delay to each other, and some soundbars and receivers call this "Auto Lip Sync" or similar.
2. Use the manual A/V sync setting on the soundbar, receiver or TV. Many offer an audio delay slider in milliseconds. Adjust while watching someone speaking.
3. Change the TV's digital audio output format. Switching between Auto, Passthrough and PCM can change the delay. Test each.
4. Connect the streaming device directly to the receiver rather than through the TV, if your receiver supports video passthrough. This removes one processing step.

Using the manual delay setting well

Manual delay settings typically adjust audio in steps of a few milliseconds. To set them:

1. Play your reference video.
2. Change the delay by one or two steps at a time.
3. Watch for at least 10–20 seconds after each change, because the effect isn't always instant.
4. Note the value that looks best, then check it with a different source, such as a different app or channel.

If the best value differs a lot between sources, the problem is probably in a particular app or input rather than your audio chain.

Step 3: Reduce TV processing delay

Heavy picture processing, such as motion smoothing and noise reduction, adds delay to the video:

• Try Game Mode briefly to test. If sync improves, picture processing is part of the cause.
• Turn off motion smoothing, sometimes called Motion Plus, TruMotion or MotionFlow, or reduce it.
• Some TVs adjust audio delay automatically in certain modes. Check for an "AV Sync" or "Lip Sync" setting.

Step 4: Check the streaming device

• Make sure the device's audio output format matches what your equipment supports. Our streaming device buying guide explains audio passthrough and Atmos support.
• Disable frame-rate matching temporarily to test. On some setups it briefly causes desync after changes.
• Restart the device. Sync can drift after long sessions on some hardware.

Device settings that commonly affect sync

• Audio output format. Passthrough sends compressed surround audio to the soundbar to decode. PCM decodes it in the streaming device. Each path has different timing.
• Match frame rate or dynamic range. Mode switches can briefly confuse sync. Some devices recover after a few seconds, while others need playback restarted.
• Volume leveling or dialogue enhancement. Extra audio processing can add delay on some devices.

Step 5: Fix sync in a player app

If you use a general-purpose player, there's usually an audio delay setting. In VLC, use Tools → Track Synchronization on desktop, or the audio delay option in the mobile apps.

Bluetooth headphones

Bluetooth audio adds noticeable delay. Many TVs and streaming devices compensate automatically, but some don't. Look for a Bluetooth audio delay setting, or use headphones that support lower-latency modes.

When the problem is the source

Sometimes the broadcast or stream itself is out of sync. Signs include:

• The problem affects one channel, one programme or one title only
• It appears on every device you try, including a phone
• It changes during the programme, for example after an ad break

In those cases, there is little you can fix at home beyond restarting playback, which can resynchronize some streams. Report it to the service with the channel, programme and time. Live channels from legitimate providers are usually corrected quickly once reported.

Lip sync in player apps and IPTV

General-purpose player apps used with live IPTV streams sometimes drift out of sync over long viewing sessions. This can happen when the stream's timing information is irregular. Restarting the stream usually fixes it. If it happens constantly with one source but not others, the source is the likely cause. Compare in a second player such as VLC.

Questions people ask

Why does sync drift only after watching for a while?

Long sessions can expose small timing errors in a stream or a device's clock handling. Restarting playback usually resynchronizes. If it happens with every source on one device, try updating or restarting the device.

Why is the delay different between apps?

Apps can use different audio formats or processing paths. One app might send surround audio for the soundbar to decode, while another sends stereo PCM. Each path has different timing. Setting a fixed audio format on the streaming device can make behaviour more consistent.

Does a better HDMI cable fix lip sync?

Rarely. Cables either carry the signal or fail in obvious ways, such as dropouts or no picture. Sync problems come from processing, not cables.

My TV and soundbar are the same brand. Why is sync still off?

Same-brand pairs often work better with automatic lip-sync, but firmware versions and specific settings still matter. Update both devices and recheck auto lip-sync settings.

A short checklist for persistent problems

• Problem confirmed on more than one channel or app
• TV picture processing reduced (motion smoothing off)
• Soundbar or receiver auto lip-sync on
• Manual A/V delay adjusted with a reliable reference
• Streaming device audio format tested (Auto, Passthrough, PCM)
• Firmware updated on TV, soundbar and streaming device
• HDMI-CEC and ARC/eARC set up correctly. See HDMI-CEC, ARC and eARC explained

If every box is ticked and the problem remains, contact the manufacturer of the device where the delay appears. Tell them your exact setup, including the connection path and audio formats.

Key takeaways

• Lip-sync problems usually come from different processing delays in the TV, soundbar and streaming device.
• Find out whether the problem affects one channel, one app, or everything. The answer tells you where to look.
• Auto lip-sync and manual audio delay settings fix most soundbar and receiver issues.
• Reducing TV picture processing can reduce video delay.
• Problems in a single programme are usually in the source. Report them to the service.

Before you buy new equipment

Lip-sync problems sometimes lead people to replace soundbars or cables unnecessarily. Before buying anything, work through the steps above, update the firmware on every device in the chain, and test with the TV's own speakers as a reference. If the TV speakers are in sync and the soundbar is not, even after adjusting its delay setting, contact the soundbar maker's support team first. Many issues are fixed in firmware updates, and support teams know which settings combinations cause problems with particular TV brands.

Summary

Sources and further reading

• HDMI Licensing Administrator
• VideoLAN Wiki: VLC documentation