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Free Lossless Audio Codec

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: The IESG <>,,,,,,
Subject: Protocol Action: 'Free Lossless Audio Codec' to Proposed Standard (draft-ietf-cellar-flac-14.txt)

The IESG has approved the following document:
- 'Free Lossless Audio Codec'
  (draft-ietf-cellar-flac-14.txt) as Proposed Standard

This document is the product of the Codec Encoding for LossLess Archiving and
Realtime transmission Working Group.

The IESG contact persons are Murray Kucherawy and Francesca Palombini.

A URL of this Internet-Draft is:

Ballot Text

Technical Summary

   This document defines the Free Lossless Audio Codec (FLAC) format and
   its streamable subset.  FLAC is designed to reduce the amount of
   computer storage space needed to store digital audio signals without
   losing information in doing so (i.e., lossless).  FLAC is free in the
   sense that its specification is open and its reference implementation
   is open-source.  Compared to other lossless (audio) coding formats,
   FLAC is a format with low complexity and can be coded to and from
   with little computing resources.  Decoding of FLAC has seen many
   independent implementations on many different platforms, and both
   encoding and decoding can be implemented without needing floating-
   point arithmetic.

Working Group Summary

The WG is very small (6-8 active participants), but pretty much the entire
active part of the WG was involved in the consensus for this document, and the
GitHub repo for this specification shows 11 people who have contributed text to
the document, and discussion of issues and pull requests usually involves 3-5
participants. More WG members spoke than were silent.

Document Quality

There are two independent implementations (libFLAC and libavcodec), plus a list
of implementations, all described in the document.

It's worth noting that one of the challenges for this draft was collecting the
long and broad FLAC implementation history, to minimize the amount of
incompatibility this spec introduces. To give some idea of this constraint,
Windows, Android, MacOS/iOS, and SerinityOS all include FLAC libraries, and
FLAC can be implemented on bare hardware, so incompatibility is not taken

An early media type review was solicited and feedback was addressed.


   The Document Shepherd for this document is Spencer Dawkins. The
   Responsible Area Director is Murray Kucherawy.

RFC Editor Note