Audio Latency - What You Need To Know

A common term used in today’s digital entertainment industry is audio latency. To help you better understand this term, we are going to explain what it is, why you don’t want it and how you can minimize audio latency for a more immersive listening experience. Now, with that being said, let’s get started:

What Is Audio Latency And Why Is It Undesirable When Watching Movies?

    The term latency is used to refer to a slight, but noticeable, time lag between a transmission being sent and when it is actually received. Audio latency is typically more noticeable when watching video content, particularly when characters on screen talk. In this case, the sound of their voices will appear out of sync with the movement of their mouths. This effect is also known as a “lip sync error” and it makes for a rather annoying viewing experience.

When Does Audio Latency Occur?

    Typically, audio latency occurs when you are watching television while listening through a pair of wireless headphones or a wireless speaker. This is because when we transmit audio wirelessly, using either Bluetooth or 2.4GHz, the audio transmission takes time to travel from the transmitter to the headphones/speaker. This is when you have latency.

How Do I Avoid/Minimize Audio Latency?

     Bluetooth devices use a range of digital audio encoder and decoders (codecs) to transfer data from the main audio source to your Bluetooth audio devices such as your headphones or loudspeakers. These codecs all have advantages and disadvantages that are unique to each. Some codecs have been specifically developed to address latency issues and these are found in higher quality or higher end Bluetooth devices.

     Although there are many different types of codecs available, all Bluetooth devices must support SBC at the very minimum. Let’s take a look at some examples of the different codecs available and what their purposes are:

• SBC (sub band codec) - most basic, ALL Bluetooth products must be able to support this. It has a noticeable 200-220 millisecond delay.

• LDAC - Sony’s proprietary BT audio codec with variable bit rate support.

• aptX - 48kHz/16-bit audio - better sound quality than SBC. Lower latency of about 100-170 milliseconds.

• aptX High Definition - 48kHz/24-bit audio - better sound quality than aptX.

• aptX Low Latency - 32-40 millisecond delay. Designed for video and gaming applications.

• FastStream - under 40 millisecond delay and support for two-way SBC audio. Not as commonly available.

* Please note that for any of these codecs to work - both the sending device (the transmitter) and the receiving device (the receiver i.e. headphones or speakers) should support the same audio codec.

While some measure of latency is inevitable while streaming audio, studies have shown that while watching TV or gaming, as long the latency is 45 milliseconds or less, it’s not noticeable and can be considered to be perfectly ‘in sync’ with the video.

So, if you’re looking into buying a pair of Bluetooth headphones or transmitter for watching TV or gaming make sure that they support either aptX Low Latency and or FastStream to ensure a fully immersive experience!

Check out this list of our Bluetooth products which are designed for watching TV and gaming:

1. Wireless headphones for TV

2. Bluetooth transmitters for TV

Many people suffer from audio latency and Bluetooth stuttering, hope this article helps you enjoy your TV time, and the article on how to deal with the Bluetooth breaking up issue will be come out soon.

Contact Avantree

     To learn more about the advantages of Bluetooth headphones, contact Avantree at support@avantree.com and shop a wide selection of premium quality headphones and accessories today. 

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FAQs

What is audio latency and why is it a problem when watching movies?
Audio latency is the delay between when a sound is sent and when it is heard, causing voices to be out of sync with lip movements on screen. This lip sync error disrupts the viewing experience by making dialogue appear disconnected from the actors’ mouth movements.

When does audio latency typically occur?
Audio latency usually happens when using wireless headphones or speakers with TVs, as transmitting audio via Bluetooth or 2.4GHz wireless takes time to travel from the source to the receiver, causing a noticeable delay between video and sound.

How can I minimize or avoid audio latency?
To reduce latency, use Bluetooth devices that support low-latency codecs like aptX Low Latency or FastStream. Both the transmitter and receiver must support the same codec to ensure minimal delay and synchronized audio with video.

What are common Bluetooth audio codecs and their latency differences?

• SBC: Basic codec with about 200ms delay.

• aptX: Better quality, 100-170ms delay.

• aptX Low Latency: Designed for video/gaming, 32-40ms delay.

• FastStream: Under 40ms delay, supports two-way audio. Choosing devices with these codecs improves sync.

What latency level is considered unnoticeable for TV and gaming?
Latency of 45 milliseconds or less is generally imperceptible to viewers and gamers, providing a fully synchronized and immersive audio-visual experience without annoying lip sync errors.

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