Bluetooth Audio Codecs | Terminology & Varieties


Bluetooth has been a blessing to the world as know-how has pushed the world in the direction of the wi-fi connection of digital units. Bluetooth connectivity is a daily factor now in music units similar to headphones. The fixed development in Bluetooth variations, in addition to audio compression codecs, has made it doable to transmit the audio sign with out shedding high quality in the way in which.

In current occasions, a number of audio codecs have flooded the market. Whereas buying a Bluetooth audio machine, the selection of audio codec is extraordinarily necessary. It is because it actually determines the audio high quality you’ll be able to anticipate from the machine. We are going to clarify all the things you might want to learn about Bluetooth audio codecs ranging from the technical terminologies to totally different audio codecs.

What Is Bluetooth Codec?

A codec is principally a know-how that compresses and decompresses knowledge for quicker and simpler transmission. A codec has two parts – an encoder to compress knowledge and a decoder to decompress knowledge. A Bluetooth codec decides how the information can be transmitted from the supply, similar to your smartphone, to the vacation spot, similar to your headphones by way of Bluetooth know-how.

The primary purpose of a Bluetooth codec is to transmit high-fidelity audio indicators at a minimal bit fee. This may assist to transmit audio indicators with minimal bandwidth and therefore, at a quicker velocity. Equally, the cupboard space and reminiscence requirement for playback can be minimal as effectively.

Observe: A low bit fee ensures better compression with lowered audio high quality. Quite the opposite, a excessive bit fee ensures lesser compression with higher audio high quality.

Why Do You Want A Codec In Bluetooth Audio Transmission?

In Bluetooth connectivity, you want a transmitter and a receiver. On this case, the Bluetooth audio transmitter is your smartphone, and the Bluetooth audio receiver is your headphone. The job of the transmitter isn’t just to ship the audio file to the receiver. It is because sending the audio file in uncooked type wirelessly will exceed the bandwidth of Bluetooth connectivity.

Relying on the standard of the recorded audio, the file dimension is decided. Top quality audio will find yourself as a big file dimension. On prime of that, standard lossless audio file codecs similar to WAV and AIFF will be sure that file dimension stays giant. Since Bluetooth connection has a restricted bandwidth, the audio connection established by means of Bluetooth will begin to stutter, and the audio high quality will undergo. That’s the reason there may be the necessity for encoding and decoding, and that’s the place a codec comes into play.

How Does Bluetooth Wi-fi Audio Transmission Work?

A Bluetooth transmitter reduces the audio file dimension utilizing an algorithm, and the audio file turns right into a compressed file. This course of is named encoding and is carried out by an encoder of the codec. The compressed file is distributed over to the Bluetooth receiver.

The compressed file isn’t a viable audio file, and therefore, it must be decompressed. This decompression motion is carried out by a decoder of the codec. After decompression, the audio file turns into playable.

The codec is an algorithm that takes audio knowledge, compresses them to cut back the dimensions, encodes in a format for transmission. The identical codec decodes the format on the receiver and makes the information playable for the person.

Each codec has its distinctive algorithm to compress audio knowledge. Compression includes decreasing audio knowledge with out decreasing high quality considerably. That’s the reason there are numerous Bluetooth audio codecs obtainable out there. We are going to talk about them intimately within the following sections.

Terminology For Bluetooth Audio Codec

Earlier than going into the totally different Bluetooth audio codecs, we have to talk about the associated terminologies on your higher understanding.

1. Pattern Fee

This refers back to the variety of knowledge factors current in an audio file per second. In easy phrases, it refers back to the frequency of the analog sign that’s transmitted. It’s measured in Hz.

2. Bit Depth

This refers back to the variety of bits per audio pattern. It’s a measurement of the audio decision and high quality. It’s represented in bits. You will note DVDs giving 24-bit whereas CDs giving 16-bit.

3. Bit Fee

This refers back to the variety of bits processed per second. It’s represented by the kilobits per second(kbps) or megabits per second(mbps).

4. Information Fee

It refers back to the knowledge transmitted per second.

5. Sampling Depth

It refers back to the decision of the audio knowledge within the file.

6. Latency

It refers back to the lag between the transmission and reception of the audio sign.

Totally different Sorts of Bluetooth Audio Codecs

1. SBC (Sub-Band Codec)

It’s the most typical codec you can see in nearly all wi-fi headphones. Nevertheless, its compression results in heavy lack of audio high quality. Its bit fee reaches a most of 345 kbps whereas its pattern fee reaches a most of 45KHz.

The explanation for the huge utilization of SBC is that it’s appropriate for transmitting adequate audio high quality at medium bit fee. Subsequently, there can be no streaming points, and the switch charges can be simply manageable. The underside line is that if a headphone comes with SBC solely, the audio high quality is not going to be superior.

2. AAC (Superior Audio Codec)

You’ll find this codec on iPhones and iPads. It’s appropriate with Android as effectively. The codec helps 320 kbps bit fee at 24-bit depth and 96Khz pattern fee. It makes use of a psychoacoustic mannequin in its compression algorithm.

iOS machine house owners are advisable to buy AAC-supported headphones for the perfect audio high quality. The favored Bose Noise Cancelling Headphones 720 has this superior audio codec and you know the way highly effective and high-quality audio output it produces.

3. AptX (Audio Processing Know-how)

The codec is designed by Qualcomm, and it ensures higher audio high quality. You’ll find it beneath totally different labels similar to AptX, AptX HD, AptX LL. They’ve totally different bit fee, pattern fee, and bit depth.

In AptX HD, the utmost bit fee is 567 kbps with pattern fee of 48 Khz and bit depth of 24-bit. In AptX, the utmost bit fee is 384 kbps with pattern fee of 48 Khz and bit depth of 16-bit. Nevertheless, each of them have latency of 170 and 270 milliseconds, respectively.

This latency drawback is solved in AptX LL the place the latency is lowered to 40 milliseconds solely. When you go for a gaming headset, you need to have low latency and therefore, AptX LL is a greater codec selection. Nevertheless, Apple doesn’t assist AptX LL.

4. AptX Lossless

AptX Lossless is likely one of the newest codecs designed by Qualcomm. It was launched within the second half of 2021. It affords a pattern fee of 44.1KHz at 16-bit depth. It’s completely appropriate for premium audio streaming because the lack of audio high quality is minimal. Nevertheless, the supply and the vacation spot have to assist the codec to make it perform correctly.

5. AptX Adaptive

AptX Adaptive got here out because the successor of AptX, nevertheless it has not achieved the recognition as anticipated. You’ll find the codec in chosen headphones solely. It’s higher than AptX, and you’ve got numerous benefits over the opposite AptX variations.

The latency is comparatively low, and therefore, it’s appropriate for avid gamers and film watchers. It may possibly obtain a most bit fee of 420 kbps, and the latency is round 80 milliseconds. The codec has backward compatibility as effectively.

6. LDAC (Lossless Digital to Analog Converter)

The codec is designed by Sony, and they’re a pioneer within the audio machine trade. The codec focuses on decreasing the lack of audio high quality throughout transmission and streaming. The utmost bit fee is 990 kbps with a pattern fee of 48KHz and a bit depth of 16 bits.

There are a great deal of units that assist LDAC codec, and also you get true HD audio high quality. Nevertheless, in the event you apply it to an Apple machine, you’ll not discover the standard variations as a result of the bit fee is toned down routinely.

There are three totally different modes obtainable – 990 kbps, 660 kbps, and 330 kbps. By default, smartphones use 330 kbps, however you’ll be able to improve it to the opposite two choices. It’s important to use high-end headphones to get the perfect of LDAC.

7. LHDC (Low-Latency and Excessive-Definition Audio Codec)

This codec is current in some high-end headphones, such because the OnePlus Buds Professional. The utmost bit fee is 900 kbps with a pattern fee of 96KHz and bit depth of 24 bits. Though it has very low latency, it’s but to make a widespread software apart from flagship headphones.

8. LC3

The newest Bluetooth model comes with LC3 codec, which ensures superior audio high quality at a low pattern fee. It’s a dream come true codec for audio geeks. You possibly can think about this to be the newest Bluetooth audio codec out there.

The codec can be delivering audio to folks utilizing listening to aids which are Bluetooth-enabled. They’ll stream any audio and nonetheless concentrate on their environment. You possibly can stream audio to a number of Bluetooth units from a single supply.

Comparability Amongst Totally different Codecs

Codec Max Bitrate Bit Depth Pattern Fee Launched Yr
SBC 320 kbps 16 bit 48.0 kHz 2003
AAC 264 kbps 16 bit 44.1 kHz 2015
aptX 352 kbps 16 bit 48.0 kHz 2009
aptX HD 576 kbps 24 bit 48.0 kHz 2016
aptX LL 352 kbps 16 bit 44.1 kHz 2016
LDAC 990 kbps 24 bit 96.0 kHz 2015
LC3 N/A N/A N/A 2020


Shopping for a Bluetooth-enabled audio machine with the newest codec might not at all times be the correct selection. It is because compatibility is necessary, and the supply machine shouldn’t tone down the audio parameters routinely. Subsequently, you need to at all times purpose for optimum audio high quality with much less necessary parameters on your understanding and simple decision-making.


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