Audio video synchronization (also known as syncing) is used to make sure that sound matches what is seen in video. When a person speaks in a movie, their lips should match the dialogue you’re hearing. Similarly, musical cues should be seamless in transitions.
Syncing is a processing that transmits audio and video signals together, often using time codes to align both. However, because audio and video signals can travel through different pathways and processing devices, delays may occur. This can lead to lip sync delay, where the sound lags behind or gets ahead of the visuals, resulting in a disjointed experience.
Why is audio visual synchronization important?
There are several reasons why audio and video syncing matters when producing video:
Enhances viewer experience
When audio and video are in sync, the experience feels natural and immersive. Out-of-sync playback can distract viewers and make them lose interest.
Professionalism
In live events or broadcasts, poorly synchronized audio and video can damage the reputation of the production team. It reflects negatively on the quality of the content.
Clear communication
In interviews, speeches, or educational videos, lip sync delay can confuse viewers. This makes it hard for them to understand or trust what others say.
Essential for live events
For live-streaming events, delays between the performer and the audience can break the illusion of immediacy, limiting the experience.
Causes of audio video sync issues
Audio and video can go out of sync for many reasons, including hardware limits and delays in software processing:
Signal processing delays
Different devices in your system, like TVs or AV receivers, process audio and video signals at different speeds. Video processing often takes longer, causing the audio to play ahead of the video.
Transmission delays
When audio and video signals travel through different cables or wireless connections, they may arrive at different times. For instance, streaming devices may experience buffering that affects one signal more than the other.
Encoding and decoding
In live streams or digital media, encoding video and audio into one stream can cause delays. Later, decoding it for playback can also add to these delays. This is common in high-resolution content or compressed media formats.
Software or device compatibility issues
Some devices or applications may not handle audio and video signals correctly, leading to synchronization errors. For example, outdated firmware on a TV or streaming device can cause delays.
How to fix delayed audio: tips to synchronize audio and video
If you have problems with synchronization, there are several ways to fix delayed audio:
Use built-in delay settings
Most modern TVs, soundbars, and AV receivers have an audio delay or “lip sync” adjustment feature. This allows you to manually delay the audio to match the video if the audio is ahead. Conversely, you can adjust video delay in some systems if the video is behind.
Sync audio and video in software
If you are watching content on a computer or editing video, many media players and editing programs offer tools. These tools help you sync audio and video. In video editing software, you can adjust the audio track to fit the video.
Update firmware and drivers
Ensure your devices have the latest firmware or drivers. Updates often fix known issues with audio video synchronization and improve performance.
Check the connections
Use high-quality HDMI or SDI cables to minimize transmission delays. Avoid splitting audio and video signals unless necessary, as this can increase the chances of desynchronization.
Use external devices
Consider using a dedicated AV processor or external synchronization device. These devices handle both audio and video signals to ensure perfect alignment.
Minimize wireless lag
If you’re using wireless speakers or soundbars, there may be inherent delays in signal transmission. Try using wired connections or upgrading to devices with lower latency.
With Resi’s Resilient Streaming Protocol (RSP), you can ensure that your audio and video signals remain synchronized during live streams. Proper setup and configuration of your equipment, along with Resi’s technology, contribute to maintaining audio-video sync, providing a seamless viewing experience for the audience.