Lyra (codec): Difference between revisions
Note that this comparison uses the older version. |
Citation bot (talk | contribs) Add: date. | Use this bot. Report bugs. | Suggested by Whoop whoop pull up | #UCB_webform 1575/2955 |
||
| Line 13: | Line 13: | ||
== Features == |
== Features == |
||
The Lyra codec is designed to transmit speech in real-time when bandwidth is severely restricted, such as over slow or unreliable network connections.<ref name=":0">{{Cite web |last=Buckley |first=Ian |date=2021-04-08 |title=Google Makes Its Lyra Low Bitrate Speech Codec Public |url=https://www.makeuseof.com/google-lyra-speech-codec-public/ |access-date=2022-07-21 |website=MakeUseOf |language=en-US}}</ref> It runs at fixed bitrates of 3.2, 6, and 9 kbps and it is intended to provide better quality than codecs that use traditional waveform-based algorithms at similar bitrates.<ref name=":2">{{Cite web |title=Lyra: A New Very Low-Bitrate Codec for Speech Compression |url=http://ai.googleblog.com/2021/02/lyra-new-very-low-bitrate-codec-for.html |access-date=2022-07-21 |website=Google AI Blog |language=en}}</ref><ref name=":4" /> Instead, compression is achieved via a [[machine learning]] algorithm that encodes the input with feature extraction, and then reconstructs an approximation of the original using a generative model.<ref name=":0" /> This model was trained on thousands of hours of speech recorded in over 70 languages to function with various speakers.<ref name=":2" /> Because generative models are more computationally complex than traditional codecs, a simple model that processes different frequency ranges in parallel is used to obtain acceptable performance.<ref name=":1">{{Cite web |date=2021-04-09 |title=Google Duo uses a new codec for better call quality over poor connections |url=https://www.xda-developers.com/google-duo-lyra-codec-better-call-quality/ |access-date=2022-07-21 |website=XDA |language=en-US}}</ref> Lyra imposes 20 ms of latency due to its frame size.<ref name=":4" /> Google's reference implementation is available for [[Android (operating system)|Android]] and [[Linux]].<ref name=":1" /> |
The Lyra codec is designed to transmit speech in real-time when bandwidth is severely restricted, such as over slow or unreliable network connections.<ref name=":0">{{Cite web |last=Buckley |first=Ian |date=2021-04-08 |title=Google Makes Its Lyra Low Bitrate Speech Codec Public |url=https://www.makeuseof.com/google-lyra-speech-codec-public/ |access-date=2022-07-21 |website=MakeUseOf |language=en-US}}</ref> It runs at fixed bitrates of 3.2, 6, and 9 kbps and it is intended to provide better quality than codecs that use traditional waveform-based algorithms at similar bitrates.<ref name=":2">{{Cite web |title=Lyra: A New Very Low-Bitrate Codec for Speech Compression |url=http://ai.googleblog.com/2021/02/lyra-new-very-low-bitrate-codec-for.html |access-date=2022-07-21 |website=Google AI Blog |date=25 February 2021 |language=en}}</ref><ref name=":4" /> Instead, compression is achieved via a [[machine learning]] algorithm that encodes the input with feature extraction, and then reconstructs an approximation of the original using a generative model.<ref name=":0" /> This model was trained on thousands of hours of speech recorded in over 70 languages to function with various speakers.<ref name=":2" /> Because generative models are more computationally complex than traditional codecs, a simple model that processes different frequency ranges in parallel is used to obtain acceptable performance.<ref name=":1">{{Cite web |date=2021-04-09 |title=Google Duo uses a new codec for better call quality over poor connections |url=https://www.xda-developers.com/google-duo-lyra-codec-better-call-quality/ |access-date=2022-07-21 |website=XDA |language=en-US}}</ref> Lyra imposes 20 ms of latency due to its frame size.<ref name=":4" /> Google's reference implementation is available for [[Android (operating system)|Android]] and [[Linux]].<ref name=":1" /> |
||
{{Listen |
{{Listen |
||
Revision as of 15:12, 9 August 2023
 | |
| Filename extension |
.lyra |
|---|---|
| Developed by | |
| Initial release | 2021 |
| Latest release | 1.3.2 December 20, 2022 |
| Type of format | Audio codec |
| Free format? | Yes (Apache-2.0) |
Lyra is a lossy audio codec developed by Google that is designed for compressing speech at very low bitrates. Unlike most other audio formats, it compresses data using a machine learning-based algorithm.
Features
The Lyra codec is designed to transmit speech in real-time when bandwidth is severely restricted, such as over slow or unreliable network connections.[1] It runs at fixed bitrates of 3.2, 6, and 9 kbps and it is intended to provide better quality than codecs that use traditional waveform-based algorithms at similar bitrates.[2][3] Instead, compression is achieved via a machine learning algorithm that encodes the input with feature extraction, and then reconstructs an approximation of the original using a generative model.[1] This model was trained on thousands of hours of speech recorded in over 70 languages to function with various speakers.[2] Because generative models are more computationally complex than traditional codecs, a simple model that processes different frequency ranges in parallel is used to obtain acceptable performance.[4] Lyra imposes 20 ms of latency due to its frame size.[3] Google's reference implementation is available for Android and Linux.[4]
Quality
Lyra's initial version performed significantly better than traditional codecs at similar bitrates.[1][4][5] Ian Buckley at MakeUseOf said, "It succeeds in creating almost eerie levels of audio reproduction with bitrates as low as 3 kbps." Google claims that it reproduces natural-sounding speech, and that Lyra at 3 kbps beats Opus at 8 kbps.[2] Tsahi Levent-Levi writes that Satin, Microsoft's AI-based codec, outperforms it at higher bitrates.[5]
History
Lyra was first announced in February 2021,[2] and in April, Google released the source code of their reference implementation.[1] The initial version had a fixed bitrate of 3 kbps and around 90 ms latency.[1][2]
A second version (v2/1.2.0), released on September 2022, improved sound quality, latency, and performance, and permitted multiple bitrates. It uses a "SoundStream" structure as opposed to the WaveNet structure of the first version.[3]
Support
Implementations
Google's implementation is available on Github under the Apache License.[1][6] Written in C++, it is optimized for 64-bit ARM but also runs on x86, on either Android or Linux.[4]
Applications
Google Duo uses Lyra to transmit sound for video chats when bandwidth is limited.[1][5]
References
- ^ a b c d e f g Buckley, Ian (2021-04-08). "Google Makes Its Lyra Low Bitrate Speech Codec Public". MakeUseOf. Retrieved 2022-07-21.
- ^ a b c d e "Lyra: A New Very Low-Bitrate Codec for Speech Compression". Google AI Blog. 25 February 2021. Retrieved 2022-07-21.
- ^ a b c "Lyra V2 - a better, faster, and more versatile speech codec". Google Open Source Blog. Retrieved 2023-04-26.
- ^ a b c d "Google Duo uses a new codec for better call quality over poor connections". XDA. 2021-04-09. Retrieved 2022-07-21.
- ^ a b c Levent-Levi, Tsahi (2021-04-19). "Lyra, Satin and the future of voice codecs in WebRTC". BlogGeek.me. Retrieved 2022-07-21.
- ^ Google (2021). "Lyra: A Very Low-Bitrate Codec for Speech Compression". GitHub. Retrieved 21 July 2022.
External links
- Lyra: A New Very Low-Bitrate Codec for Speech Compression Google blog post with a demonstration comparing codecs
See also
- Satin (codec), an AI-based codec developed by Microsoft
- Comparison of audio coding formats
- Speech coding
- Videotelephony