How Do Bluetooth Codecs Work? Which One Is Best?

Audiophiles argue that Bluetooth headphones sound weaker when compared to wired ones. While that’s true, Bluetooth technology has come a long way since its inception. Today, you can choose from a number of codecs that significantly improve your audio experience.

In this guide, we’ll explain what Bluetooth codecs are, how they work, and the seven codecs found in the Bluetooth audio realm. We’ll also compare them side-by-side and help you choose the right ones for your needs.

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What Are Bluetooth Codecs? How Do They Work?

A Bluetooth codec is a software program that enables wireless transmission between an audio source and an audio player. It encodes data received from the source and transmits it to the compatible player, where the same codec decodes this data.

Simply put, it’s a channel through which audio travels from your phone to your Bluetooth headphones. The goal is to transmit audio with minimum data loss and minimum delays—imitating wired audio quality.

7 Bluetooth Codecs You Should Know

1. aptX Codecs

aptX, short for Audio Processing Technology, is a family of codecs owned by Qualcomm. All modern Android devices come with aptX codecs, but not iOS devices. The following are the codecs of the aptX family, each designed to prioritize different features:

aptX: aptX is the first of the bunch and is known for its low latency and high audio quality, making it the standard Bluetooth codec in the audio industry. Although there are other specialized variants available, aptX continues to be a prominent choice for professionals and laymen alike.

aptX HD: aptX HD was developed to mimic high-res audio via Bluetooth. Transmitting high-quality audio requires sending bigger audio files with less compression. This increases latency due to the limited bandwidth of Bluetooth connections. Yet, aptX HD manages to offer HD audio with decently low latency.

aptX Adaptive: aptX Adaptive addresses the pain point of patchy and glitchy sound due to signal fluctuations. This problem arises when the codec tries to output high-quality audio when the signal is weak. aptX Adaptive solves this by adjusting the audio quality as per the signal strength, eliminating audio inconsistency.

Image Credit: Rydo87/Wikimedia

aptX Low Latency: aptX Low Latency prioritizes reducing the delay in audio-to-video synchronization. To enable this, the codec heavily compresses audio to reduce file size, which helps transmit audio quickly—decreasing latency. But the downside is that the audio quality will be slightly lower than the other aptX variants.

aptX Lossless: aptX Lossless is the newest addition to the lot. Unlike other variants of aptX, it supports lossless audio, provided that the signal strength is strong enough. This is a treat for audiophiles since not many codecs offer this level of fidelity.

aptX Live: aptX Live is designed to prioritize microphone output in wireless microphones and in-ear monitors. This is mostly used in live performances where the microphone input needs the majority of the Bluetooth bandwidth. The recorded audio is then compressed and transmitted.

Related: In-Ear Monitor Buying Guide: Things to Check

2. LDAC

Image Credit: Sony/Wikimedia

LDAC was developed by Sony and is a close competitor to aptX Adaptive in terms of features. Similar to aptX Adaptive, LDAC adjusts its performance as per the signal strength. The only difference is that LDAC switches between three pre-set audio qualities while aptX Adaptive can freely slide between a range.

Related: aptX vs. LDAC: What’s the Difference?

3. AAC

Standing for Advanced Audio Codec, AAC is the standard codec on iOS devices. However, it is found on most Android devices too. Contrary to other codecs, AAC uses psychoacoustics to reduce file size for quick transmission. Its performance is nerfed in the Android ecosystem, but iOS is optimized to take full advantage of it.

4. SBC

SBC, short for Low Complexity Sub-band Coding, is and does the bare minimum for Bluetooth transmission. Both Android and iOS devices have this codec, but you almost definitely don’t want to use it over other codecs. Not only does it provide poor audio quality, but it also suffers from latency issues.

5. LHDC

Image Credit: LHDC

Low-Latency High-Definition Codec (LHDC) is developed by the High-res Wireless Audio (HWA) Union and Savitech. All Android devices with Android 10 and above support this codec, while iOS devices don’t. It offers a high audio quality while still keeping its latency fairly low.

It also has a low latency sibling called LHDC LL or LLAC (Low Latency Audio Codec). Its latency is quite similar to aptX Low Latency but has better audio quality as it can improve its performance as per the signal strength.

6. LC3

Low Complexity Communication Codec (LC3) is a relatively new codec developed by Fraunhofer IIS and Ericsson to bring Bluetooth capabilities into hearing aids. It allows the transmission of multiple audio streams simultaneously. This helps people who are hard of hearing to listen to music while still being able to hear their surroundings.

7. Samsung Scalable Codec

Samsung Scalable Codec (SSC) is quite similar to aptX Adaptive and is compatible only with Samsung devices. It was first seen in the Samsung Galaxy Buds and is designed to reduce choppy audio. It freely adjusts its performance to enable smoother audio output.

Which Bluetooth Codec Is the Best?

There isn’t one codec that performs well in all situations. As Bluetooth codec technology is still under-development, there is always a trade-off between audio quality and latency.

Bitrate, sample rate, and bit depth contribute to the overall sound quality. The higher they are, the more accurate the reproduced sound will be. Meaning, you can hear tracks the way the original artist intended. The following spec table will help you put things into perspective.

Related: Are Expensive Headphones Worth It? Things You Should Know Before Buying

Bluetooth Codecs Spec Table

Codec

Bitrate

Max Sample Rate

Max Bit Depth

Latency

aptX

384kbps

48kHz

16-bit

50–150ms

aptX HD

566kbps

48kHz

24-bit

~150ms

aptX Adaptive

279–420kbps

48kHz

24-bit

80ms

aptX Low Latency

352kbps

44.1kHz

16-bit

40ms

aptX Lossless

~1mbps

96kHz lossy/44.1kHz lossless

24-bit lossy/16-bit lossless

(unavailable)

aptX Live

(unavailable)

48kHz

24-bit

1.8ms

LDAC

330/660/990kbps

96kHz

24-bit

~200ms

AAC

264kbps

44.1kHz

24-bit

150–250ms

SBC

320kbps

48kHz

16-bit

150–250ms

LHDC

990kbps

96kHz

24-bit

(unavailable)

LLAC

440/660kbps

48kHz

24-bit

30ms

LC3

160–345kbps

48kHz

32-bit

30ms

Samsung Scalable

88–512kbps

96kHz

24-bit

(unavailable)

Which Bluetooth Codec Should I Use?

Bluetooth earbuds alongside smartphone

No single codec is the best for everything, but plenty of them get the job done in most cases. Depending on your usage, the suitable codecs will vary. Let’s take a closer look.

Usage

Features Required

Suitable Codecs

Casual listening

High audio quality

aptX Lossless, LDAC, LHDC, aptX HD

Watching videos

Low latency

LLAC, aptX Adaptive, aptX Low Latency, LC3

Calling

Consistent audio quality

aptX Adaptive, aptX, Samsung Scalable, LC3

Gaming

Low latency, consistency

LLAC, LC3, aptX Low Latency, aptX Adaptive

Choose a Codec Right for You

Many of these codecs will sound very similar unless you’re an audiophile. So, what matters the most is the headphone–source compatibility. Both your device and headphones should support the same codec you want to use, otherwise, they will default to any other codec available.

While Android users have many options, iOS users have to choose between SBC and AAC. So, the next time you’re buying Bluetooth headphones, make sure to check the codecs they support and their specs to get the best experience possible out of them.