Opus release 1.5.2

This minor release fixes several build issues that were discovered since
the 1.5 release. It also fixes a misalignment issue in the AVX2 code
that could cause crashes under Windows.

Opus release 1.5.1

Fixed meson build from Opus 1.5.
Opus 1.5 is the first release to make extended use of ML in the encoder and
decoder. Major changes since 1.4 include:
- Significant improvement to packet loss robustness using Deep Redundancy (DRED)
- Improved packet loss concealment through Deep PLC
- Low-bitrate speech quality improvements down to 6 kb/s wideband
- Improved x86 (AVX2) and ARM (Neon) optimizations
- Support for 4th and 5th order ambisonics

Opus release 1.5

Opus 1.5 is the first release to make extended use of ML in the encoder and
decoder. Major changes since 1.4 include:
- Significant improvement to packet loss robustness using Deep Redundancy (DRED)
- Improved packet loss concealment through Deep PLC
- Low-bitrate speech quality improvements down to 6 kb/s wideband
- Improved x86 (AVX2) and ARM (Neon) optimizations
- Support for 4th and 5th order ambisonics

Opus release 1.4

Opus 1.4 brings the following improvements and fixes:
- Improved tuning of the Opus in-band FEC (LBRR). See the
  https://gitlab.xiph.org/xiph/opus/-/issues/2360 for details
- Added a OPUS_SET_INBAND_FEC(2) option that turns on FEC, but does not
  force SILK mode (FEC will be disabled in CELT mode)
- Improved tuning and various fixes to DTX
- Added Meson support, improved CMake support

In addition to the improvements above, this release includes many minor
bug fixes.

Opus 1.3.1

Opus 1.3.1 is a minor release that fixes an issue with the analysis on files
with digital silence (all zeros), especially on x87 builds (mostly affects
32-bit builds). It also includes two new features:
- A new OPUS_GET_IN_DTX query to know if the encoder is in DTX mode (last frame
  was either a comfort noise frame or not encoded at all)
- A new (and still experimental) CMake-based build system that is eventually
  meant to replace the VS2015 build system (the autotools one will stay).

Opus release 1.3

Opus 1.3 is the latest major release of Opus and brings many improvements,
including:
- The spec fixes in RFC 8251 are now enabled by default
- Improvements to the VAD and speech/music classification using an RNN
- Improvements to stereo speech coding at low bitrate
- Support for ambisonics coding using mappings 2 and 3
- Making it possible to use SILK down to bitrates around 5 kb/s
- Using wideband encoding down to 9 kb/s
- Minor quality improvement on tones
- Security improvements

Notable bug fixes include:
- Fixes to the CELT PLC
- Bandwidth detection fixes

Opus release 1.3-rc2

This is a second release candidate for the upcoming 1.3 release and includes:
- Fixing an issue with bandwidth detection
- Ambisonics support now exabled by default
- Ambisonics now uses families 2 and 3 (instead of experimental 253 and 254)
- Hardening is now enabled by default

Opus release 1.3-rc

This is a release candidate for the upcoming 1.3 release and includes:
- Making it possible to use SILK down to bitrates around 5 kb/s
- Using wideband encoding down to 9 kb/s
- Improving security (including a new --enable-hardening option)
- Minor quality improvement on tones
- Improving Ambisonics support (still experimental)
- Minor bug fixes

Opus release 1.3-beta

This is a beta release towards the upcoming 1.3 release. Changes include:
- The spec fixes in RFC 8251 are now enabled by default
- Improvements to the VAD and speech/music classification using an RNN
- Improvements to stereo speech coding at low bitrate
- Added support for ambisonics projection using mapping 3 (disabled by default)
- Fixes to the CELT PLC

Opus 1.2.1 release

This fixes an issue where the encoder can misdetect that the signal is SWB
instead of FB, lowpassing the signal. This patch makes the encoder much more
careful about doing that.