The preservation of audiovisual materials faces challenges from technological obsolescence, analog media deterioration, and the use of proprietary  formats that lack formal open standards. While obsolescence and material degradation are widely addressed, the standardization of open, transparent, self-descriptive, lossless formats remains an important mission to be undertaken by the open source community.
 
FFV1 is a lossless video codec and Matroska is an extensible media container based on EBML (Extensible Binary Meta Language), a binary XML format. There are open source implementations of both formats, and an increasing interest in and support for use of FFV1 and Matroska. However, there are concerns about the sustainability and credibility of existing specifications for the long-term use of these formats. These existing specifications require broader review and formalization in order to encourage widespread adoption.
 
There is also a need for a lossless audio format to complement the lossless video codec and container format. FLAC is a lossless audio codec that has seen widespread adoption in a number of different applications including archival applications. While there are open source implementations of the codec, no formal standards for either the codec itself or its use in container formats currently exist. Review and formalization of the FLAC codec standard and its use in Matroska container formats is needed for wider adoption.
 
Using existing work done by the development communities of Matroska, FFV1, and FLAC, the Working Group will formalize specifications for these open and lossless formats. In order to provide authoritative, standardized specifications for users and developers, the Working Group will seek consensus throughout the process of refining and formalizing these standards. Initial specifications can be accessed here:
 
Specifications:
- FFV1: https://mediaarea.net/temp/ffv1.html
- Matroska: http://matroska.org/technical/specs/index.html
- EBML: http://matroska-org.github.io/libebml/specs.html
- FLAC: https://xiph.org/flac/format.html

Development Versions:
- FFV1: https://github.com/ffmpeg/ffv1
- Matroska: https://github.com/Matroska-Org/foundation-source/blob/master/spectool/specdata.xml
-  EBML: https://github.com/Matroska-Org/ebml-specification
 
The Working Group will seek consensus and refinements for specifications for both FFV1 and Matroska in order to provide authoritative, standardized specifications for users and developers. Backward compatibility with existing versions 0-3 of the FFV1 and Matroska specifications will be an important goal, while also reviewing and refining the current version 4 under active development. Although not encouraged, non-backwards-compatible changes to the input specifications will be acceptable if the Working Group determines that the modifications are required to meet the group's technical objectives, provided that the reasons for these changes are clearly documented. 
 
Deliverables:
- Informational specification for Matroska container format versions 1, 2 and 3 to IESG for publication
- Standards Track specification for Matroska container format version 4 to IESG for publication
- Informational specification for FFV1 video codec versions 0, 1 and 3 to IESG for publication
- Standards Track specification for FFV1 video codec version 4 to IESG for publication
- Standards Track specification for FLAC audio codec to IESG for publication