LDAC (codec)
{{Short description|Digital audio encoding technology}}
{{Use dmy dates|date=November 2019}}
{{Infobox file format
| name = LDAC
| icon = 200px
| owner = Sony
| genre = Audio codec
}}
LDAC (Lossless Digital Audio Codec) is a proprietary audio coding technology developed by Sony, which allows streaming lossy audio over Bluetooth 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.{{Cite web |title=Sony Corporation - LDAC™ site for end-users {{!}} Experience Your Music in Hi-Res Audio. Bringing You A Hi-Res Audio & Wireless Music Experience with LDAC |url=https://www.sony.net/Products/LDAC/info/ |access-date=2025-04-15 |website=www.sony.net}} 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
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.{{cite web|url=https://www.themasterswitch.com/best-wireless-headphones#4.1vsaptxbluetooth|title=Best Wireless Headphones of 2018|date=2017-11-13|access-date=2018-03-09}}
LDAC utilizes a type of lossy compression{{cite web|url=https://darko.audio/2017/03/the-inconvenient-truth-about-bluetooth-audio/|title=The inconvenient truth about Bluetooth audio|last=Darko|first=John H.|date=2017-03-29|website=DAR__KO|access-date=2018-01-13}}{{cite web|url=https://www.avhub.com.au/news/sound-image/what-is-sony-ldac-and-how-does-it-do-it-408285|title=What is Sony LDAC, and how does it do it?|date=2015-08-24|website=AVHub|access-date=2018-01-13}} by employing a hybrid coding scheme based on the modified discrete cosine transform{{Cite web|url=https://android.googlesource.com/platform/external/libldac/+/master/src/ldaclib_api.c#691|title=src/ldaclib_api.c - platform/external/libldac |website=android Git repositories - Git at Google}} and Huffman coding{{Cite web|date=2017-08-22|title=What you need to know about Sony's LDAC|url=https://www.androidauthority.com/sony-ldac-codec-790690/|access-date=2021-01-08|website=Android Authority|language=en-US |first1=Robert |last1=Triggs }} 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;{{Cite web|url=https://www.soundguys.com/ldac-ultimate-bluetooth-guide-20026/|title=The ultimate guide to Bluetooth headphones: LDAC isn't Hi-res|date=2018-12-16|website=SoundGuys|language=en-US |first1=Robert |last1=Triggs |access-date=2019-09-22}} however, audio bitrate and resolution can be manually adjusted on Linux (when using PipeWire{{Cite web|title=Releases · PipeWire / pipewire|url=https://gitlab.freedesktop.org/pipewire/pipewire/-/releases|access-date=2021-06-11|website=GitLab|language=en}}), 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", LDAC is part of the Android Open Source Project, enabling every OEM to integrate this standard into their own Android devices freely.{{Cite web|url=https://android.googlesource.com/platform/external/libldac|title=platform/external/libldac |website=android Git repositories - Git at Google|language=en|access-date=2018-11-30}} The encoder library is open source and the implementation for Linux is already present in bluez-alsa,{{Cite web|url=https://github.com/Arkq/bluez-alsa/issues/104|title=LDAC support? · Issue #104 · Arkq/bluez-alsa|website=GitHub|language=en|access-date=2019-03-20}} pulseaudio-modules-bt,{{Citation|last=H.H|first=Bao|title=Adds Sony LDAC, aptX, aptX HD, AAC codecs (A2DP Audio) support to PulseAudio on Linux: EHfive/pulseaudio-modules-bt|date=2019-03-20|url=https://github.com/EHfive/pulseaudio-modules-bt|access-date=2019-03-20}}{{Cite web|url=https://eischmann.wordpress.com/2019/02/11/better-bluetooth-sound-quality-on-linux/|title=Better Bluetooth sound quality on Linux|last=eischmann|date=2019-02-11|website=Brno hat|language=en|access-date=2019-03-20}} and in PipeWire's bluez5 module.{{Cite web|url=https://gitlab.freedesktop.org/search?utf8=%E2%9C%93&snippets=false&scope=commits&repository_ref=master&search=ldac&group_id=10138&project_id=4753|title=List of commits on the PipeWire project pertaining to LDAC support|date=2020-12-31|website=freedesktop.org Gitlab|language=en|access-date=2020-12-31}}{{Cite web|url=https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/249|title=Achieve parity and/or surpass PulseAudio in Bluetooth audio support|date=2020-12-31|access-date=2020-12-31}} It is available on Fedora since Fedora 29.{{Cite web|url=https://bugzilla.redhat.com/show_bug.cgi?id=1671064|title=1671064 – Review Request: libldac - LDAC library from AOSP|website=bugzilla.redhat.com|access-date=2019-03-20}} However the decoder library is proprietary, so receiving devices require licenses.{{Cite web|title=Audio over Bluetooth: most detailed information about profiles, codecs, and devices|url=https://habr.com/en/post/456182/|website=habr.com|language=en|access-date=2020-05-09}}
On 17 September 2019, the Japan Audio Society (JAS) certified LDAC with their Hi-Res Audio Wireless certification.{{Cite web |last=Yeow |first=Goh Beng |date=2019-09-17 |title=Japan Audio Society certifies LHDC™ for "Hi-Res Audio Wireless" certification |url=https://porta-fi.com/japan-audio-society-certifies-lhdc/ |access-date=2019-09-22 |website=Porta-Fi™ |language=en-GB}} 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.{{cite web |date=2024-06-12 |title=Definition of Hi-Res Audio (Announced on June 12th 2014) |url=https://www.jas-audio.or.jp/english/hi-res-logo-en |access-date=2024-06-26 |website=Japan Audio Society}}
See also
References
{{Reflist}}
External links
- {{Official website|https://www.sony.net/Products/LDAC/}}
- [https://android.googlesource.com/platform/external/libldac LDAC codec source code] in the Android Open Source Project
{{Compression formats}}