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{{Short description|Digital audio encoding technology}}
{{more footnotes|date=December 2017}}
{{Use dmy dates|date=November 2019}}
{{Infobox file format
{{Infobox file format
| icon = [[Image:LDAC_logo.tiff|200px]]
| name = LDAC
| icon = [[File:LDAC_logo.tiff|200px]]
| owner = [[Sony]]
| owner = [[Sony]]
| genre = [[Audio codec]]}}
| genre = [[Audio codec]]
}}
'''LDAC''' ('''L'''ossless '''D'''igital '''A'''udio '''C'''odec) is a [[proprietary software|proprietary]] [[audio codec|audio coding]] technology developed by [[Sony]], which allows streaming [[high-resolution audio]] over [[Bluetooth]] connections at up to 990 kbps at 32 bits/96 kHz. 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.
'''LDAC''' is an [[audio codec|audio coding]] technology developed by [[Sony]], which allows streaming audio over [[Bluetooth]] connections up to 990 kbit/s at 24bit/96khz (also called [[High-resolution audio]]). It is used by various Sony products, including headphones, smartphones, portable media players, active speakers and home theaters. LDAC is a [[Lossy audio compression|lossy]] codec<ref name="Darko 2017">{{cite web | last=Darko | first=John H. | title=The inconvenient truth about Bluetooth audio | website=DAR__KO | date=2017-03-29 | url=http://www.digitalaudioreview.net/2017/03/the-inconvenient-truth-about-bluetooth-audio/ | access-date=2018-01-13}}</ref><ref name="AVHub 2015">{{cite web | title=What is Sony LDAC, and how does it do it? | website=AVHub | date=2015-08-24 | url=http://www.avhub.com.au/news/sound-image/what-is-sony-ldac-and-how-does-it-do-it-408285 | access-date=2018-01-13}}</ref>, which employs a hybrid coding scheme based on the [[MDCT]]<ref name="libldac source code">{{cite web | title=libldac android source code | url=https://android.googlesource.com/platform/external/libldac/+/master/src/ldaclib_api.c#691}}</ref> to provide more efficient data compression. Its main competitor is Qualcomm's [[AptX#aptX-HD|aptX-HD]] technology. While not directly competitive in terms of bitrate, [[Advanced Audio Coding|AAC]] is used by Apple for its flagship mobile phones and is supported on their Mac branded personal computers. <ref>{{cite web | title="Best Wireless Headphones of 2018" | date=2017-11-13 | url=https://www.themasterswitch.com/best-wireless-headphones#4.1vsaptxbluetooth | access-date=2018-03-09}}</ref>


==Audio coding==
Starting from [[Android 8.0]] '[[Android version history#Android 8.0 Oreo (API 26)|Oreo]]', LDAC is part of the [[Android Open Source Project]], enabling every OEM to integrate this standard into their own Android devices freely.<ref>{{cite web|url=http://www.androidauthority.com/sony-ldac-codec-790690/|title=What you need to know about Sony's LDAC|date=22 August 2017|publisher=}}</ref>
LDAC is an alternative to [[Bluetooth Special Interest Group|Bluetooth SIG]]'s [[SBC (codec)|SBC]] codec. Its main competitors are Huawei's L2HC, Qualcomm's [[AptX#aptX HD|aptX-HD]]/[[AptX#aptX Adaptive|aptX Adaptive]] and the [[HWA Union]]/[[Savitech]]'s [[LHDC (codec)|LHDC]].<ref>{{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}}</ref>

LDAC utilizes a type of [[lossy audio compression|lossy]] compression<ref name="Darko 2017">{{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}}</ref><ref name="AVHub 2015">{{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}}</ref> by employing a hybrid coding scheme based on the [[modified discrete cosine transform]]<ref name="libldac source code">{{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}}</ref> and Huffman coding<ref name="androidauthority">{{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 }}</ref> to provide more efficient data compression. By default, LDAC audio bitrate settings are set to Best Effort, which switches between discrete bitrate steps ([[Constant bitrate|CBR]]) 330/660/990 kbps depending on connection strength;<ref name="soundguys">{{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}}</ref> however, audio bitrate and resolution can be manually adjusted on Linux (when using PipeWire<ref>{{Cite web|title=Releases · PipeWire / pipewire|url=https://gitlab.freedesktop.org/pipewire/pipewire/-/releases|access-date=2021-06-11|website=GitLab|language=en}}</ref>), 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.<ref name="soundguys"/> Lossless audio transmission can be achieved by manually configuring the codec's resolution to 44.1 kHz, 16 bits and selecting 'Sound quality preferred' for high bitrate streaming at 909 kbps. This setup is identical to a wired audio or an Audio-CD sound quality.{{Citation needed|date=April 2024}}

Starting from [[Android 8.0]] "[[Android version history#Android 8.0 Oreo (API 26)|Oreo]]", LDAC is part of the [[Android Open Source Project]], enabling every OEM to integrate this standard into their own Android devices freely.<ref name="androidauthority" /><ref>{{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}}</ref> The ''encoder'' library is open source and the implementation for Linux is already present in bluez-alsa,<ref>{{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}}</ref> pulseaudio-modules-bt,<ref>{{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}}</ref><ref>{{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}}</ref> and in PipeWire's bluez5 module.<ref>{{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}}</ref><ref>{{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}}</ref> It is available on Fedora since Fedora 29.<ref>{{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}}</ref> However the ''decoder'' library is [[Proprietary software|proprietary]], so receiving devices require licenses.<ref>{{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}}</ref>

On 17 September 2019, the Japan Audio Society (JAS) certified LDAC with their Hi-Res Audio Wireless certification.<ref>{{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}}</ref> As of June 2024, the codecs certified by the JAS to bear the Hi-Res Audio Wireless logo are [[LHDC (codec)|LHDC]], LDAC, [[SCL6]], [[LC3 (codec)#LC3plus|LC3plus]], SHDC, and [[aptX Adaptive]].<ref>{{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}}</ref>

== See also ==
* [[Lossy data compression]]
* [[List of codecs]]


==References==
==References==
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== External links ==
== External links ==
* {{Official website|https://www.sony.net/Products/LDAC/}}
* {{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]]
* http://www.sony.com.au/microsite/hiresaudio/ldac.html


{{Compression formats}}
{{Compression formats}}


[[Category:Audio codecs]]
[[Category:Audio codecs]]
{{multimedia-software-stub}}

Latest revision as of 03:49, 17 December 2024

LDAC
Developed bySony
Type of formatAudio codec

LDAC (Lossless Digital Audio Codec) is a proprietary audio coding technology developed by Sony, which allows streaming high-resolution audio over Bluetooth connections at up to 990 kbps at 32 bits/96 kHz. 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]

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.[1]

LDAC utilizes a type of lossy compression[2][3] by employing 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 discrete bitrate steps (CBR) 330/660/990 kbps depending on connection strength;[6] however, audio bitrate and resolution can be manually adjusted on Linux (when using PipeWire[7]), 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.[6] Lossless audio transmission can be achieved by manually configuring the codec's resolution to 44.1 kHz, 16 bits and selecting 'Sound quality preferred' for high bitrate streaming at 909 kbps. This setup is identical to a wired audio or an Audio-CD sound quality.[citation needed]

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.[5][8] The encoder library is open source and the implementation for Linux is already present in bluez-alsa,[9] pulseaudio-modules-bt,[10][11] and in PipeWire's bluez5 module.[12][13] It is available on Fedora since Fedora 29.[14] However the decoder library is proprietary, so receiving devices require licenses.[15]

On 17 September 2019, the Japan Audio Society (JAS) certified LDAC with their Hi-Res Audio Wireless certification.[16] 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.[17]

See also

[edit]

References

[edit]
  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. ^ "src/ldaclib_api.c - platform/external/libldac". android Git repositories - Git at Google.
  5. ^ a b Triggs, Robert (22 August 2017). "What you need to know about Sony's LDAC". Android Authority. Retrieved 8 January 2021.
  6. ^ a b Triggs, Robert (16 December 2018). "The ultimate guide to Bluetooth headphones: LDAC isn't Hi-res". SoundGuys. Retrieved 22 September 2019.
  7. ^ "Releases · PipeWire / pipewire". GitLab. Retrieved 11 June 2021.
  8. ^ "platform/external/libldac". android Git repositories - Git at Google. Retrieved 30 November 2018.
  9. ^ "LDAC support? · Issue #104 · Arkq/bluez-alsa". GitHub. Retrieved 20 March 2019.
  10. ^ 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
  11. ^ eischmann (11 February 2019). "Better Bluetooth sound quality on Linux". Brno hat. Retrieved 20 March 2019.
  12. ^ "List of commits on the PipeWire project pertaining to LDAC support". freedesktop.org Gitlab. 31 December 2020. Retrieved 31 December 2020.
  13. ^ "Achieve parity and/or surpass PulseAudio in Bluetooth audio support". 31 December 2020. Retrieved 31 December 2020.
  14. ^ "1671064 – Review Request: libldac - LDAC library from AOSP". bugzilla.redhat.com. Retrieved 20 March 2019.
  15. ^ "Audio over Bluetooth: most detailed information about profiles, codecs, and devices". habr.com. Retrieved 9 May 2020.
  16. ^ Yeow, Goh Beng (17 September 2019). "Japan Audio Society certifies LHDC™ for "Hi-Res Audio Wireless" certification". Porta-Fi™. Retrieved 22 September 2019.
  17. ^ "Definition of Hi-Res Audio (Announced on June 12th 2014)". Japan Audio Society. 12 June 2024. Retrieved 26 June 2024.
[edit]
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