LDAC (codec)
| LDAC | |
|---|---|
| File:LDAC logo.tiff | |
| Internet media type | {{#property:P1163}} |
| Developed by | Sony |
| Type of format | Audio codec |
LDAC is a proprietary, lossy audio coding technology developed by Sony,[1] designed for streaming audio over Bluetooth connections at up to 990 kbps at 32 bits/96 kHz.[citation needed] It is used by various products, including headphones, earphones, smartphones, portable media players, active speakers, and home theaters.
The encoder of LDAC is open-source under Apache License 2.0, so that any device can be coded to transmit LDAC streams without patent or licensing issues. The decoder design remains proprietary.
Audio coding
[edit | edit source]LDAC is an alternative to Bluetooth SIG's SBC codec. Its main competitors are Huawei's L2HC, Qualcomm's aptX-HD/aptX Adaptive and the HWA Union/Savitech's LHDC.[2]
LDAC utilizes a type of lossy compression[3][4] by employing a hybrid coding scheme based on the modified discrete cosine transform[5] and Huffman coding[6] to provide more efficient data compression. By default, LDAC audio bitrate settings are set to Best Effort, which switches between discrete bitrate steps (CBR) 330/660/990 kbps depending on connection strength;[7] however, audio bitrate and resolution can be manually adjusted on Linux (when using PipeWire[8]), some Android platforms (which generally requires access to the "Developer Settings" menu), and Sony's own smartphones and Walkman devices at the following rates; 330/660/990 kbps at 96/48 kHz and 303/606/909 kbps at 88.2/44.1 kHz with depth of 32, 24 or 16 bits.[7]
Starting from Android 8.0 "Oreo", LDAC is part of the Android Open Source Project, enabling every OEM to integrate this standard into their own Android devices freely.[6][9] The encoder library is open source and the implementation for Linux is already present in bluez-alsa,[10] pulseaudio-modules-bt,[11][12] and in PipeWire's bluez5 module.[13][14] It is available on Fedora since Fedora 29.[15] However the decoder library is proprietary, so receiving devices require licenses.[16]
On 17 September 2019, the Japan Audio Society (JAS) certified LDAC with their Hi-Res Audio Wireless certification.[17] As of June 2024, the codecs certified by the JAS to bear the Hi-Res Audio Wireless logo are LHDC, LDAC, SCL6, LC3plus, SHDC, and aptX Adaptive.[18]
See also
[edit | edit source]References
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