LDAC (Lossless Digital Audio Codec) is a proprietary

audio coding An audio coding format (or sometimes audio compression format) is a content representation format for storage or transmission of digital audio (such as in digital television, digital radio and in audio and video files). Examples of audio coding f ...

technology developed by

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

, which allows streaming

lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...

audio over

Bluetooth Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is li ...

connections at up to 990 kbps at 32 bits/96 kHz. Despite this, Sony markets LDAC as "lossless" and "high-resolution," declaring the quality to be better than true lossless, high-resolution audio. It is used by various products, including

headphones Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an ...

earphones Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an ...

smartphones A smartphone is a mobile phone with advanced computing capabilities. It typically has a touchscreen interface, allowing users to access a wide range of applications and services, such as web browsing, email, and social media, as well as mult ...

, 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

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. LDAC utilizes a type of

compression by employing a hybrid coding scheme based on the

modified discrete cosine transform The modified discrete cosine transform (MDCT) is a transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where s ...

and

Huffman coding In computer science and information theory, a Huffman code is a particular type of optimal prefix code that is commonly used for lossless data compression. The process of finding or using such a code is Huffman coding, an algorithm developed by ...

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; however, audio bitrate and resolution can be manually adjusted on Linux (when using PipeWire), 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. Starting from Android 8.0 "

Oreo Oreo (; stylized in all caps) is an American brand of sandwich cookie consisting of two cocoa biscuits with a sweet fondant filling. Oreos were introduced in 1912 by Nabisco, and the brand has been owned by Mondelez International since its me ...

", LDAC is part of the

Android Open Source Project Android is an operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen-based mobile devices such as smartphones and tablets. Android has historically been developed by ...

, enabling every OEM to integrate this standard into their own Android devices freely. The ''encoder'' library is open source and the implementation for Linux is already present in bluez-alsa, pulseaudio-modules-bt, and in PipeWire's bluez5 module. It is available on Fedora since Fedora 29. However the ''decoder'' library is proprietary, so receiving devices require licenses. On 17 September 2019, the Japan Audio Society (JAS) certified LDAC with their Hi-Res Audio Wireless certification. 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.

References

External links

*
LDAC codec source code
in the

{{Compression formats Audio codecs

Audio coding

See also

References

External links