LDAC (codec)

LDAC is a proprietary audio coding technology (encoder is open under Apache 2.0 license) developed by Sony, which allows streaming high-resolution audio over Bluetooth connections at up to 990 kbps at 32 bit/96 kHz. It is used by various Sony products, including headphones, smartphones, portable media players, active speakers and home theaters.

LDAC (codec)
Developed bySony
Type of formatAudio codec

LDAC is an alternative to Bluetooth SIG's SBC and LC3 codecs. Its main competitors are Qualcomm's aptX-HD/aptX Adaptive and the HWA Union/Savitech's LHDC.[1]

LDAC is a lossless and lossy codec,[2][3] which employs a hybrid coding scheme based on the Modified discrete cosine transform[4] and Huffman coding[5] to provide more efficient data compression. By default, LDAC audio bitrate settings are set to Best Effort, which switches between 330/660/990 kbps depending on connection strength,[6] however, audio bitrate and resolution can be manually adjusted on some Android platforms, Sony 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. When the codec is set to 16 bits/44.1kHz at 909 kbps (or 16 bits/48kHz at 990 kbps) LDAC can stream lossless audio that is identical in quality to (or slightly higher than) Audio CD or standard resolution uncompressed audio.[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.[8][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 is a work in progress in the PipeWire bluez5 module.[13][14] It is available on Fedora with RPM Fusion since Fedora 30.[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. Currently the only codecs with the Hi-Res Audio Wireless certification are LDAC and LHDC.[17]

See also

References
  1. "Best Wireless Headphones of 2018". 13 November 2017. Retrieved 9 March 2018.
  2. Darko, John H. (29 March 2017). "The inconvenient truth about Bluetooth audio". DAR__KO. Retrieved 13 January 2018.
  3. "What is Sony LDAC, and how does it do it?". AVHub. 24 August 2015. Retrieved 13 January 2018.
  4. "libldac android source code".
  5. "What you need to know about Sony's LDAC". Android Authority. 22 August 2017. Retrieved 8 January 2021.
  6. "The ultimate guide to Bluetooth headphones: LDAC isn't Hi-res". SoundGuys. 16 December 2018. Retrieved 22 September 2019.
  7. "The ultimate guide to Bluetooth headphones: LDAC isn't Hi-res". SoundGuys. 16 December 2018. Retrieved 7 January 2021.
  8. "What you need to know about Sony's LDAC". 22 August 2017.
  9. "platform/external/libldac - Git at Google". android.googlesource.com. Retrieved 30 November 2018.
  10. "LDAC support? · Issue #104 · Arkq/bluez-alsa". GitHub. Retrieved 20 March 2019.
  11. H.H, Bao (20 March 2019), Adds Sony LDAC, aptX, aptX HD, AAC codecs (A2DP Audio) support to PulseAudio on Linux: EHfive/pulseaudio-modules-bt, retrieved 20 March 2019
  12. eischmann (11 February 2019). "Better Bluetooth sound quality on Linux". Brno hat. Retrieved 20 March 2019.
  13. "List of commits on the PipeWire project pertaining to LDAC support". freedesktop.org Gitlab. 31 December 2020. Retrieved 31 December 2020.
  14. "Achieve parity and/or surpass PulseAudio in Bluetooth audio support". 31 December 2020. Retrieved 31 December 2020.
  15. "1671064 – Review Request: libldac - LDAC library from AOSP". bugzilla.redhat.com. Retrieved 20 March 2019.
  16. "Audio over Bluetooth: most detailed information about profiles, codecs, and devices". habr.com. Retrieved 9 May 2020.
  17. Yeow, Goh Beng (17 September 2019). "Japan Audio Society certifies LHDC™ for "Hi-Res Audio Wireless" certification". Porta-Fi™. Retrieved 22 September 2019.
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