June 18, 2003

File Format Licensing Information

I've collected some information on the licensing of various file formats and how open they are as a result. The summary is that Ogg Vorbis and PDF are open, or "open enough" for our purposes, while Windows Media, RealMedia, MP3, MPEG, and Macromedia's Flash format (SWF) are not.

Ogg Vorbis: This is a new format that was defined to replace MP3 and other audio formats that have licensing issues (technically Ogg is a container format and Vorbis is a specific compression scheme). If you read the Ogg Vorbis FAQ, under "Licensing", it is made quite clear that "the Ogg Vorbis specification is in the public domain" and "there are no licensing fees for any use of the Ogg Vorbis specification."

PDF: This is Adobe's format, used in Acrobat and various other tools. Although PDF is covered by a number of Adobe patents, according to Adobe's Legal Notices page, the patents "are licensed on a royalty-free, non-exclusive basis for the term of each patent and for the sole purpose of developing software that produces, consumes, and interprets PDF files that are compliant with the Specification." Furthermore, the license can only be terminated if the terms are violated. After some discussion on the ODFI mailing list, it was decided that PDF is "open enough."

SWF: SWF is the format used to encode Macromedia Flash animations. According to the SWF license page, "No fees are required for access to the Macromedia Flash file format (SWF) or for the creation of products based on the SWF format." However, if you read the actual license, nobody is allowed to redistribute the spec (although anyone can, right now, get his or her own copy), and the license also states "You understand and agree that Macromedia may amend, modify, change, and cease distribution or production of the Specification at any time". Since Macromedia is reserving the right to effectively close the spec, it should not be considered open (despite the name of the website OpenSWF that discusses the format).

MP3/MPEG: Patents on MPEG (MP3 is short for "MPEG layer 3") are owned by the Fraunhofer Institute. According to the Licensing page, Fraunhofer has farmed the licensing out to other companies: Via Licensing for MPEG 2/4-AAC (audio), MPEG LA for MPEG-4 (video), and Thomson for MP3 (audio). The royalties vary, but are along similar schemes: PC Software royalties for the MP3 patents are 75 cents per unit (or a $50,000 one-time fee) for decoders (playback) and $2.50 per unit for encoders; MPEG-4 is 25 cents per unit for decoders and/or encoders, MPEG-2 AAC varies from 10 cents to 45 cents for decoders and/or encoders (based on unit volume), etc. Since these formats require license fees, they are not open.

Windows Media: Microsoft has its own audio and video formats used by Windows Media encoders and players; the Licensing page discusses the various royalties (and compares them to royalties for some other formats). For example, the audio format is licensed for 10 cents per decoder, 20 cents per encoder, or 25 cents per encoder/decoder. The royalties are higher on embedded systems than on PC software, and furthermore the page states that "No royalties are due on distributions of 'PC Software' versions designed to operate on versions of Windows operating systems." The format, needless to say, is not considered open.

RealMedia: This is the format used by Real's encoders and players. While the licensing page is somewhat confusing, it appears that Real does not license the format per se; it licenses binaries and even the source code in some instances (for free), but not the format itself for a set royalty. The client source code license talks about "the RealMedia File Format reader, the Real Data Transport network stack implementation, the RealNetwork Client-Server Challenge implementation" etc. which are the technologies that Real is trying to maintain control of. These are the key technologies, so the format is not open.

As an added note, the streaming done by Windows Media and Real are also not open. According to this article in Network Computing [2/19/01], open standards for streaming do exist: "RTSP (Real-Time Streaming Protocol) is an application-layer IETF protocol that allows the interaction between player and server to enable starting, pausing and transfer of information such as stream title. RTP (Real-Time Transport Protocol) is an IETF packet format for transmitting real-time media over UDP. Its companion, RTCP (Real-Time Transport Control Protocol), synchronizes media at the client and reports packet loss to the server."

However, as the article goes on to say, ""Streaming-media vendors have developed alternative proprietary protocols to handle server-to-client media transmission and server-to-server communication. Thus, RealNetworks uses Real Data Transport (RDT) instead of RTCP, and Microsoft's Windows Media Technologies relies on the Microsoft Media Server (MMS) and Media Streaming Broadcast Distribution (MSBD) protocols."

Posted by Adam Barr at June 18, 2003 11:17 AM | TrackBack