Normally, earphones are considered to support high-quality audio as long as they support AAC, aptX, and LDAC audio coding.
How to turn on high quality audio?
Path: Settings > Bluetooth > Click the icon to the right of earphones > Use high-quality audio
Common audio codec formats are SBC, AAC, aptX, LDAC
SBC (Sub-band coding):
The earliest format should be SBC, which is the encoding format mandatory by the A2DP (Advanced Audio Distribution Profile) protocol. All Bluetooth supports this protocol, so all Bluetooth audio chips will also support this protocol. But because the Bluetooth transfer intermediate device needs transcoding, for example, MP3 files, the transcoding process is MP3->PCM->SBC->PCM, each transcoding will lose details, resulting in SBC hearing is worse than the original P3. Bluetooth transmission does not support AAC. SBC is used for aptx transmission and the sound quality is normal.
AAC（Advanced Audio Coding):
AAC is a technology provided by Dolby Laboratories to the music community and is a high compression ratio coding algorithm. In practice, it is believed that AAC has better hearing than MP3 at the same bit rate. When Bluetooth supports AAC format files and phones also support AAC transmission, the sound quality is much better than SBC, which can be heard by ordinary people.
aptX：
Digital audio compression algorithm based on subband ADPCM (SB-ADPCM) technology. AptX in Bluetooth wireless audio transmission field has better hearing because of its low latency, good fault tolerance and high sound quality.
LDAC：
LDAC transmits about three times as much data as normal Bluetooth*1 (at a maximum transmission speed of *2 at 990 kbps), allowing you to listen to music near Hi-Res Audio*3 while listening to it wirelessly.