How To Correct Audio/Video Synchronization Problems in Home Theater

Voice and video don't match? Check out some ways to correct it.

TV With Home Theater Speakers
TV With Home Theater Speakers. Image provided by Getty Images - imaginima -GoodLifeStudio - Collection E+

Have you ever watched a TV program, DVD, or Blu-ray Disc movie and notice that the sound and video don't match? You are not alone.

One of the problems in home theater is the issue of audio-video synchronization (also referred to as lip-sync). In order to have a good home theater experience, the audio and video have to match-up.

However, what sometimes happens is that you may notice that the audio soundtrack is slightly ahead of the video image, making when watching a high definition cable/satellite/streaming program or upscaled DVD, Blu-ray, or Ultra HD Blu-ray disc video on an HD/4K Ultra HD TV or video projector.

This is especially noticeable on close-up images of people speaking (thus the term lip-sync). It is almost as if you are watching a badly dubbed foreign movie.

What Causes Audio/Video Lip-Sync Problems

The main reason that lip-sync problems occur is that audio can be processed a lot faster than the video, especially high-definition or 4K video. High definition or 4K video takes up a lot of space and takes longer to process than audio formats or standard resolution video signals.

As a result, when you have a TV, video projector, or home theater receiver that does a lot of video processing to the incoming signal (such as signals that are upscaled from standard resolution to 720p, 1080i, 1080p, or even 4K), then the audio and video can become out of synch, with the audio arriving before the video. However, there are some cases where the video may be ahead of the audio.

Audio Video Sync Correction Adjustment Tools

If you find that you have a lip-sync problem where the audio is ahead of the video, the first thing to do is disable all of the additional video processing settings in your TV, such as motion enhancement, video noise reduction, or other picture enhancement features.

Also, if you have a home theater receiver that is performing video processing tasks, try the same procedure, as you may be adding more delay be having video processing occurring both in the TV and home theater receiver.

If making these setting modifications on your TV and or home theater receiver corrects the situation, then add each feature back on either the TV or receiver until the audio and video get out of sync again.

You can use this as your lip-sync reference point.

If curtailing the TV or home theater receiver's video processing features doesn't work, or you need to have those features on, to further assist in solving the problem of out-of-sync audio and video, there are tools available in the operating menu on many TVs, home theater receivers, and some source components, referred to as either "Audio Sync," "Audio Delay," or "Lip Sync". Some Sound Bar systems also have a variation of this feature.

Regardless of the terminology used, what these tools all have in common are settings that "slow down" or delay the arrival of the audio signal so that image on the screen and audio soundtrack match. The settings offered usually range from 10ms to 100ms and sometimes up to 240 ms (milliseconds). In some cases, the audio delay may be offered in both positive and negative terms just in case the video is ahead of the audio. Although settings based on milliseconds seems miniscule in terms of time, a 100ms change between the timing of the audio and video can be very noticeable.

Also, if you are using a home theater receiver that features Audio Return Channel via HDMI connection, you may have the option to set this function so that AV sync can be corrected automatically or manually.

If you have a home theater receiver or TV that provides this choice, try both options and see which one gives you the most consistent correction result.

In addition, if the audio/video sync problem is with just one source (such as your Blu-ray Disc/Ultra HD Blu-ray player, media streamer, or cable/satellite box), check to see if they have their own audio/video sync settings that you can take advantage of.

Possible Audio and Video Connection Solutions

For DVD and Blu-ray, and Ultra HD Blu-ray disc players, another thing you can try is to split your audio and video connections between the TV (or video projector) and home theater receiver.

In other words, instead of connecting the HDMI output of your player to a home theater receiver for both audio and video, try a setup where you connect the HDMI output of your player directly to the TV for video only and make a separate connection to your home theater receiver for audio only.

The final thing to try is to turn everything off and reconnect your audio to your home theater receiver and the home theater receiver to the TV. Turn everything back on and see if everything resets.

The Bottom Line

Settling into that comfy chair for home movie night can get turned upside down when the sound and picture don't match. However, you may have several tools available in your TV and audio system that can correct the situation.

However, If you find that the setting or audio/video connection options available on your home theater receiver, sound bar, TV, or video projector don't solve this problem, definitely contact tech support for your components for additional assistance.

Another thing to note is that it is possible that you may find that only a specific cable/satellite, or streaming program or channel is out-of-sync, and maybe only on occasion. Although this is annoying, in these cases, it may not be something on your end. It could be either a temporary or chronic problem with the specific content provider - in which case, you should contact them for assistance, or at least alert them to the problem.

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