Matroska uses a few open source initiative approved open source licenses to enable availability of source code and to accept contributions from individuals and corporations.Contributor License Grants
All individual contributors of ideas, code, or documentation to Matroska will be required to complete, sign, and submit an Individual Contributor License Grant. The agreement clearly defines the terms under which intellectual property has been contributed to the Matroska. This license is for your protection as a contributor as well as the protection of the project; it does not change your rights to use your own contributions for any other purpose.
For a corporation that has assigned employees to work on Matroska, a Corporate Contributor License Grant is available. This version of the Grant allows a corporation to authorize contributions submitted by its designated employees and to grant copyright and patent licenses. Note that a Corporate Contributor License Grant does not remove the need for any developer to sign their own Individual Contributor License Grant as an individual, to cover any of their contributions which are not owned by the corporation signing the Corporate Contributor License Grant.