What is a Bluetooth codec and which one offers the best audio quality?

If you want the best quality out of your Bluetooth audio, it's worth reviewing some settings.

Codec comes from the words "coder" and "decoder," and is the method in which your audio data is communicated from the source to your Bluetooth headphones or speakers. They're essentially like different languages — they're all communicating the same thing (your audio files), but doing so differently depending on the codec. Each codec has different limitations, as do the devices you're using. Even Bluetooth itself, despite improvements over the years , can only handle so much data: it caps out at around 2 Mbps, and no Bluetooth device can currently handle true lossless audio unless they simultaneously utilize a Wi-Fi connection.

Which Bluetooth codec is best is situational, dependent upon what devices you're using to send and receive audio and the quality of the audio itself. To best understand the difference between codecs, there are a few different measurements that are important to know. In simplified terms, it all comes down to bits of data.

Bit rate: How much data is sent per second; the more data that can be sent at once, the more of the original quality of the audio is preserved

Audio bit depth: This is the number of bits in each second of audio, which impacts the highs and lows of audio able to be communicated on the other side; the higher the bit depth, the better the dynamic range

Sample rate (kHz): The sample rate of the music per second — essentially how many times a snapshot of the audio is captured. The more it's sampled, the more accurate the snapshot. The most common sample rate in music production is 44.1kHz, which means that 44,100 snapshots are captured per second.

The standard codec is SBC, which is receivable by and included on every Bluetooth device. For all other codecs, it's a case-by-case basis for whether they'll be compatible with your device, making it important to check the finer details on your headphones or speakers. Some codecs, like the Sony-developed LDAC and Samsung Scalable, are proprietary, making the tech that supports it more niche. Though AptX codecs are more widely supported, it's still a family of codecs owned by Qualcomm, meaning that some (like AptX HD) require specific licensing if you want to, say, use it on your PC. Looking at just the raw data, this is how the most common Bluetooth codecs compare.

sdx15/Shutterstock Looking at just the raw data, this is how the most common Bluetooth codecs compare:

There are still other factors to consider when dubbing one codec "best." Just because a certain codec has a higher bit rate than another, it may still compress audio less efficiently — this is the case with SBC versus AAC, where the latter utilizes a more complex algorithm. Other variables and limitations apply as well, like the fact that SBC can have a bit rate of up to 345 kbps, but manufacturers often limit this to 256kbps to prevent battery drain.

Similarly, LDAC, AptX Adaptive and Lossless, LHDC and LC3 all use variable bit rates, adjusting based on the strength of your connection, so you may not reap the full benefits of the codec.