Back أوبوس Arabic Opus (àudio) Catalan Opus (kompresní formát) Czech Opus (lydformat) Danish Opus (Audioformat) German Opus (códec) Spanish Opus (audio kodeka) Basque اپاس Persian Opus (äänenpakkaus) Finnish Opus Interactive Audio Codec French

Opus (audio format)

Opus
Filename extension
.opus[1]
Internet media typeaudio/ogg[2]
audio/opus (RTP)[3]
Developed byIETF codec working group
Initial releaseSeptember 11, 2012 (2012-09-11)
Type of formatLossy audio
Contained byOgg, Matroska, WebM, MPEG-TS, ISOBMFF, CAF
Extended fromSILK, CELT
StandardRFC 6716
Open format?Yes
Free format?Yes
Websiteopus-codec.org
libopus
Developer(s)Xiph.Org Foundation
Initial releaseAugust 26, 2012 (2012-08-26)
Stable release
1.5.2 / April 12, 2024 (2024-04-12)
Written inC89
PlatformCross-platform
TypeAudio codec, reference implementation
License3-clause BSD license
WebsiteOpus codec downloads

Opus is a lossy audio coding format developed by the Xiph.Org Foundation and standardized by the Internet Engineering Task Force, designed to efficiently code speech and general audio in a single format, while remaining low-latency enough for real-time interactive communication and low-complexity enough for low-end embedded processors.[4][5] Opus replaces both Vorbis and Speex for new applications, and several blind listening tests have ranked it higher-quality than any other standard audio format at any given bitrate until transparency is reached, including MP3, AAC, and HE-AAC.[6][7]

Opus combines the speech-oriented LPC-based SILK algorithm and the lower-latency MDCT-based CELT algorithm, switching between or combining them as needed for maximal efficiency.[4] Bitrate, audio bandwidth, complexity, and algorithm can all be adjusted seamlessly in each frame. Opus has the low algorithmic delay (26.5 ms by default)[8] necessary for use as part of a real-time communication link, networked music performances, and live lip sync; by trading off quality or bitrate, the delay can be reduced down to 5 ms. Its delay is exceptionally low compared to competing codecs, which require well over 100 ms, yet Opus performs very competitively with these formats in terms of quality per bitrate.[9]

As an open format standardized through RFC 6716, a reference implementation called libopus is available under the New BSD License. The reference has both fixed-point and floating-point optimizations for low- and high-end devices, with SIMD optimizations on platforms that support them. All known software patents that cover Opus are licensed under royalty-free terms.[10] Opus is widely used as a voice over IP (VoIP) codec in applications such as Discord,[11] WhatsApp,[12][13][14] and the PlayStation 4.[15]

  1. ^ "MIME Types and File Extensions". XiphWiki.
  2. ^ Terriberry, Timothy; Lee, Ron; Giles, Ralph (April 2016). "Content Type". Ogg Encapsulation for the Opus Audio Codec. IETF. p. 30. sec. 9. doi:10.17487/RFC7845. RFC 7845. Retrieved 2016-04-30.
  3. ^ Spittka, Julian; Vos, Koen; Valin, Jean-Marc (2015-06-30). "Opus Media Type Registration". RTP Payload Format for the Opus Speech and Audio Codec. IETF. p. 9. sec. 6.1. doi:10.17487/RFC7587. ISSN 2070-1721. RFC 7587. Retrieved 2015-06-30.
  4. ^ a b "Opus Codec". Opus (Home page). Xiph.org Foundation. Retrieved July 31, 2012.
  5. ^ Bright, Peter (2012-09-12). "Newly standardized Opus audio codec fills every role from online chat to music". Ars Technica. Retrieved 2014-05-28.
  6. ^ Cite error: The named reference testsummary was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference 96kListeningTest was invoked but never defined (see the help page).
  8. ^ Jean-Marc Valin; Gregory Maxwell; Timothy B. Terriberry; Koen Vos (October 17–20, 2013). "High-Quality, Low-Delay Music Coding in the Opus Codec" (PDF). www.xiph.org. New York, NY: Xiph.Org Foundation. p. 2. Archived from the original (PDF) on 14 July 2018. Retrieved 19 August 2014. CELT's look-ahead is 2.5 ms, while SILK's look-ahead is 5 ms, plus 1.5 ms for the resampling (including both encoder and decoder resampling). For this reason, the CELT path in the encoder adds a 4 ms delay. However, an application can restrict the encoder to CELT and omit that delay. This reduces the total look-ahead to 2.5 ms.
  9. ^ Chen, Raymond (April 1, 2011). "Opus Testing" (PDF). Retrieved 2016-01-02.
  10. ^ Cite error: The named reference OpusLicense was invoked but never defined (see the help page).
  11. ^ "What Features Does Discord Have?". Discord. Retrieved 2017-10-29.
  12. ^ Cite error: The named reference Register was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Srivastava was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Hazra was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference playstation was invoked but never defined (see the help page).
From Wikipedia, the free encyclopedia · View on Wikipedia

Developed by Tubidy