Bluetooth audio is gaining a lot of followers today. The disappearance of the mini-jack ports for headphones on some smartphones, such as the iPhone, has led to audio companies producing high quality wireless devices. Among bluetooth audio technology, the Qualcomm aptX code is in a privileged place.

What is a bluetooth codec?

The word codec, when we talk about wireless audio, means the software’s method to encode a stream of audio information that is sent wirelessly between two devices. In other words, it is the process by which zeros and ones, of binary digital data, acquire format. It is used to transmit stereo audio through a source device, such as a telephone, a computer, television etc …, to a receiver, such as wireless speakers or headphones.
Different codecs send the audio information using different formats, they can also introduce their own compression technologies to maintain a balance between the sound quality and the information package of the audio files. Compression may sound negative for lovers of high quality audio, but it is necessary if we are going to send heavy files wirelessly.
This means that the variants between bluetooth codecs are compatible with different audio devices, in addition to providing different connection and sound qualities. All bluetooth devices support the standardized SBC (Low Complexity Subband Coding) codec, but SBC implementations have varied in quality throughout the history of this technology. To offer greater consistency to users of bluetooth products, several companies have developed their own bluetooth codecs, and then offer the license to other producing houses. AAC is one of these formats, the successor of MP3, used by Apple and others. Sony has its LDAC codec and Qualcomm offers aptX.

AptX, SBC and AAC codecs, which one is the best?

The codecs are coding algorithms that compress audio to handle sound packets and thus achieve fast wireless transmission. The effectiveness of the codec determines the quality of the audio information that will be sent. The SBC code is the standard algorithm for most bluetooth devices. However, this codec has a relatively high latency and can be somewhat noisy. The three main codecs, which most users will encounter, are SBC, AAC and aptX:

SBC

It is the code found in most wireless devices and with which all the bluetooth headphones that have the A2DP (Advance Distribution Profile) profile have. It is capable of transmitting up to 328kbps with sample rates of 44.1 Khz. It provides very decent quality audio and does not require much processing. However, audio may be inconsistent in some situations. This is notable especially when using cheap bluetooth transmitters.

AAC

Similar to SBC but provides better sound quality. This codec is very popular thanks to the Apple iTunes platform. As against, we must mention that it is not very comfortable to find it in headphones.

aptX

Ideal for demanding audio applications as it encodes audio more efficiently and accepts more information than the SBC. It has additional variations, such as aptX (LL) and aptX (HD), which drastically reduce latency in the wireless connection and improve sound quality. However, it is somewhat limiting because both the transmitter and the receiver must have the aptX capability for this codec to work.