What is aptX? Understand the importance of the codec for your Bluetooth headset
aptX is a codec present in many smartphone models and wireless devices such as Bluetooth speakers and headsets. In its traditional version, it is capable of playing audio files of up to 384 Kb/s (Kilobits per second), 48 kHz frequency, and 16-bit resolution. However, in recent years, Qualcomm has released new versions that decrease latency (such as aptX LL) and support higher quality sound files (such as aptX HD).
However, to take advantage of them, both the source and the headset or speaker must be compatible with the version. Below you can learn more about aptX technology and how it can improve the sound quality of your Bluetooth device.
Source: https://www.techidence.com/what-is-aptx-understand-the-importance-of-the-codec-for-your-bluetooth-headset/