This version fixes two minor bugs with 0.11 that affect the bit-stream. The quality should improve (very) slightly, but not enough to be noticeable in most cases. Several Opus-related bugs have also been fixed.
This release brings many quality improvements, mostly through better bit allocation. It also fixes many bugs and regressions, most notably with VBR support. The bit-stream is not compatible with version 0.9.x.
This release mainly focuses on quality improvements. The transient handling code has been greatly improved and high-frequency artifacts have been reduced. There have also been lots of small improvements from better tuning of various parameters.
This release fixes some bugs introduced in 0.8.0. The bit-stream remains compatible with 0.8.0, with the caveat that CELT no longer supports frame sizes that have prime factors larger than 5. This should not affect any reasonable application.