With audio out of sync, you can forget about immersion. Desyncs happen for different reasons - it may be a flaw of the video file, or a delay between your computer and Bluetooth speakers. But, in any case, this issue is surprisingly easy to fix. Read on to learn how to fix out-of-sync audio on macOS and Windows.
There are three common causes for audio sync problems. Generally, ways to synchronize audio and video are the same for all for them, but it’s useful knowledge either way.
First of all, it could be a problem with the video you’re watching. In this case, the creator of the video didn’t bother to synchronize the tracks. This can be fixed in most modern media players by adjusting the audio delay. Obviously, it’s not as easy when you’re viewing a desynchronized stream on the internet. Also, sometimes video and audio tracks have different durations and play at different speeds, which makes perfect sync impossible, especially when the media is one or more hours long.
Bluetooth audio hardware is another possible desync source. Bluetooth is about as fast as cables, which is why it works without delay for keyboards, mice, and gamepads. But its bandwidth is narrow, less than a cable, so it requires audio to be compressed. Compression and decompression create a noticeable delay. It’s getting smaller on newer devices, but it’s not perfect yet. If you need to eliminate sound delay in games or streamed media, wired headphones or speakers are the only way. But if you only need to sync up video files, then that can be done in a media player.
Finally, audio (or video) delay can appear in an HD-home-cinema kind of setup, due to the sheer volume of data that UHD and lossless sound require. We’ll take a separate look at the ways to fix TV sound desync.
If you have a video with its audio out of sync, and you’re on macOS, we recommend Elmedia Player. It has an option to adjust audio delay, which will work in most cases. It’s also accessible via hotkeys. To check if you’ve managed to sync the tracks correctly, try finding a moment in the video where the desync is easy to notice - for example, face close-ups during dialogue.
You can also try syncing up one scene, and then checking another scene closer to the end of a movie. If one of them plays correctly, but the other one’s broken, it probably means that the audio track was encoded at a different speed, and can only be fixed in a video editor.
Windows also has a multimedia player that can synchronize sound - it’s VLC. Just like Elmedia Player, it simply introduces a delay, or a negative delay, that lets you correct the starting time of the audio track to match the video.
If you have a single video that you rewatch often, like a good movie, then re-syncing it every time can get annoying. In that case, it may be better to just edit it and fix the file once and for all. This can even be done in iMovie - the default video editor on macOS. By the way, a video editor can resolve an issue that adjustable sound delay won’t fix - different track speeds.
Convert carefully if you want to preserve the quality of your movie! When exporting, it’s probably better to select “Custom” quality and set the bitrate manually - any conversion, positive or negative, will cause defects.
Desync issues can show up on TV as a result of video or audio processing, either by the TV itself, or the sequence of devices that leads up to it. That includes WiFi dongles, recorders, amplifiers, etc., so you can try to troubleshoot the problem by disconnecting them one-by-one and seeing which one is causing the delay.
If you have video and audio out of sync, but you’re only using a TV and a single connected device (or even none at all), then it’s worth checking the settings. Disable any and all processing options you can find.
Even though audio desync is a common issue, it’s often fixable with the right software, like Elmedia Player or VLC. The difficult fixes, like using different cables or configuring passthrough hardware are more rare, so don’t worry. Now that you’ve learned how to fix audio and video out of sync, the next step is simply enjoying your favorite media.