As there have been additions to the libFLAC interfaces, the libFLAC version number is incremented to 14. The libFLAC++ version number is incremented to 11.

• General
  • Multithreaded encoding is now possible in libFLAC and through the flac command line tool
  • The GFDL license file is updated to version 1.3
  • The markdown tool documentation is now also converted to HTML, for bundling with systems that do not read manpages (e.g. Windows)
  • Decoding of chained Ogg FLAC files is now possible (philippe44, Martijn van Beurden)
  • Various fixes (Sam James, Miroslav Lichvar, Cristian Rodríguez, manxorist, kgroeneveld, Lee Carré, Jevin Sweval, braheezy, Wolfgang Stöggl)
  • Is is now possible in libFLAC, libFLAC++ and metaflac to write to a new file when changing metadata, instead of needing to overwrite an existing file
• flac
  • Testing mode (flac -t) now parses all metadata blocks and warns the user when ID3v1 metadata is detected
  • A warning is displayed when frame numbers do not increase correctly throughout a file
  • The explain option (-H or --explain) is now removed, use the manpage or html tool documentation instead
  • Built-in help and tool documentation are improved (H2Swine)
  • When re-encoding a FLAC file from an existing FLAC file, a check is added that the MD5 sums of both files are the same
• libFLAC and libFLAC++
  • The library interfaces have been extended. See the porting guide (part of the API documentation)
  • An error is sent when a frame is missing
  • The algorithm of the ‘loose mid side’ option has changed. Instead of checking every few frames which option is best and keeping that for the next few frames, a fast heuristic is now used. This was necessary to enable multithreading
  • Most level 0 metadata interface functions now also work with Ogg FLAC files
  • When encoding Ogg FLAC files, the callback now returns a number of samples instead of always 0 (Jesper Larsson, ziplantil)
  • When changing metadata, libFLAC now detects when an input file is a symlink, and will refuse to write data to it when an in-place rewrite of the metadata cannot happen
  • When encoding using seektable templates, unused seekpoints (with a sample number higher than the total number of samples) are converted to placeholders
• Build system
  • Fix building on Android with API version < 24 (Steve Lhomme)
  • The microbench utility has been removed
  • Enable building with emscripten (werner mendizabal)
  • Minimum CMake version required (when building with CMake) is now formally 3.12
• Testing/validation
  • Improve fuzzing of allocation failures
  • Various other fuzzing improvements
• Documentation
  • The FLAC format is now specified in RFC 9639
  • The foreign metadata storage format used by the flac command line tool is now properly documented