Older/Historic Releases
libopus 1.0.1-RC3
This is a third release candidate for the upcoming 1.0.1 release. This release includes documentation fixes, portability improvements, and build file fixes, including a generic Makefile.unix.
- Source code: opus-1.0.1-rc3.tar.gz
libopus 1.0.1-RC2
This is a second release candidate for the upcoming 1.0.1 release. This release includes documentation fixes, and it should now be possible to build on Windows.
- Source code: opus-1.0.1-rc2.tar.gz
libopus 1.0.0-RC
This is a release candidate for the final 1.0 release. Other than the RFC number in the comments, this code is expected to be the same as the final RFC and 1.0 release.
- Source code: opus-1.0.0-rc.tar.gz
libopus 1.0.1-RC
This is a release candidate for the upcoming 1.0.1 release. The release includes minor updates (mostly related to the build system) that did not make it to the upcoming RFC.
- Source code: opus-1.0.1-rc.tar.gz
libopus 0.9.14
This version matches version -14 of the draft and fixes minor issues brought up before the upcoming IETF last call. There is no change to the bit-stream.
- Source code: opus-0.9.14.tar.gz
- Internet-Draft: draft-ietf-codec-opus-14.txt
Libopus versions 0.9.11-0.9.13 were skipped to synchronize release and draft numbering.
opus-tools 0.1.4
This release fixes several resampling bugs and greatly increases resampler performance. It also provides working Unicode filename and tag support for Windows (Unicode worked for Mac and *nix previously).
- Source code: opus-tools-0.1.4.tar.gz
opus-tools 0.1.3
This release adds proper multichannel WAV output from opusdec, disables the non-working '--stereo' and '--mono' mixdown switches, and uses linear predictive coding to generate padding on the final frame to reduce the risk of clicking with gapless playback.
- Source code: opus-tools-0.1.3.tar.gz
opus-tools 0.1.2
Numerous small fixes including piped audio on Windows and clicking on resampled audio.
- Source code: opus-tools-0.1.2.tar.gz
libopus 0.9.10
This version matches version -12 of the draft and fixes minor issues brought up before the upcoming IETF last call. There is no change to the bit-stream.
- Source code: opus-0.9.10.tar.gz
- Internet-Draft: draft-ietf-codec-opus-12.txt
libopus 0.9.9
This version matches version -11 of the draft. The bit-stream has not changed, except for some corner cases that are unlikely to happen in the real world.
- Source code: opus-0.9.9.tar.gz
- Internet-Draft: draft-ietf-codec-opus-11.txt
libopus 0.9.8
This version matches version -10 of the draft and fixes several glitches caused by mode switching and other corner cases. This required breaking the bit-stream for the SILK-only stereo and hybrid stereo modes. Fortunately, these modes are not often used, so few users should be affected. This release also implements a CBR mode for SILK mode. This release includes a much better test suite and has been extensively tested in multiple configurations. See the Jenkins build system and the resulting floating-point coverage and fixed-point coverage. Now that the analysis and documentation of the code has been completed, further changes to the bit-stream until the final freeze are unlikely.
- Source code: opus-0.9.8.tar.gz
- Internet-Draft: draft-ietf-codec-opus-10.txt
libopus 0.9.6
This is a cleanup release for version -08 of the draft. The bit-stream remains tentatively frozen.
- Source code: opus-0.9.6.tar.gz
- Internet-Draft: draft-ietf-codec-opus-08.txt
libopus 0.9.5
This is a cleanup release for version -07 of the draft. The bit-stream is tentatively frozen. It will not change unless a major issue is found or if for some reason the Working Group decides something needs to be change.
- Source code: opus-0.9.5.tar.gz
- Internet-Draft: draft-ietf-codec-opus-07.txt
libopus 0.9.2
Opus libopus 0.9.2 adds support for glitchless switching between the voice and audio mode. Also, the encoder now defaults to a new "automatic" mode and bandwidth selection and attempts to select the optimal mode and bandwidth considering the bit-rate and voice content. Several bugs were also fixed and the codec and test tools should be more robust in general.
- Source code: opus-0.9.2.tar.gz
- Internet-Draft: draft-ietf-codec-opus-04.txt
libopus 0.9.1
Opus libopus 0.9.1 fixes a few minor bugs that were found in version libopus 0.9.0. Unfortunately, this has required slight changes to the bit-stream, which is thus not compatible with libopus 0.9.0. This release adds support for forward error correction (FEC), which improves performance under packet loss.
- Source code: opus-0.9.1.tar.gz
- Internet-Draft: draft-ietf-codec-opus-03.txt

