UbuntuHelp:FreeFormats
来自Ubuntu中文
This document provides a short explanation of what a Free format is, along with some specific information on the range of Free formats which are available for you to use.
Warning - patent and copyright laws operate differently depending on which country you are in. Please obtain legal advice if you are unsure whether a particular patent or restriction applies to a format you wish to use in your country.
目录
What is a Free format?
Some file formats are proprietary, which means that they are owned by a company or other organisation. Sometimes, the owners of such formats charge licensing fees or impose legal restrictions on the use of their formats. This means that people may be unable to use or distribute these formats without first paying a fee or applying for a license.
A Free or open format is one which can be used by anyone, free of legal restrictions on how they use the format. Free formats are very popular - the World Wide Web is based on the open HTML standard. Ubuntu supports many free formats and the open-source community as a whole encorages their wider use.
There are a number of Free formats which are preferred over patent and copyright encumbered formats. Keep in mind that some formats (like PDF or Flash) often have public or semi-public specifications but have some restrictions imposed by their patent-holders. Some replacement formats are listed here:
|| Restricted Format || Preferred format || || MP3, AAC, WMA || Ogg Vorbis|| || WMV, AVI, MPEG-4 || Ogg Theora || || doc, xls, ppt || OpenDocument format ||
Purchasing equipment that supports free formats
Electronic equipment, such as portable audio players, often support only a handful of different formats. Often, these will be proprietary formats which the manufacturer of the device has obtained a license to use or similar. As such, it can sometimes be difficult to find a product which is able to use a chosen Free format. This section provides advice on purchasing equipment which can make use of Free formats.
Audio
If you are interested in purchasing new players (e.g. portable audio players), please refer to VorbisHardware to see what equipment is able play these formats.
Specific format / application information
This section provides information on format-specific issues and lists alternatives to popular non-free formats.
Audio
Many popular audio formats are non-free and are strongly legally protected in some countries. There are superior Free formats available, however.
MP3
MP3 is patent-encumbered, for both encoding and decoding. These patents are being actively enforced, so usage and development of MP3-programs is not encouraged. Consider using Ogg Vorbis, which is a free and higher quality alternative to MP3 (you just need to buy audio equipment more carefully).
Other free audio formats:
Video
Some video formats are also subject to strong legal restrictions in certain countries, or use copy-protection methods which are non-free.
DVD
Non-encrypted DVDs should play, however be aware that mpeg2-video is somewhat patent encumbered and the support for it is not installed by default in Ubuntu.
Full DVD-Video support requires support for the Content Scrambling System (CSS). Though the encryption is weak, using libdvdcss to avoid this is classed as a 'circumvention device' and as such is illegal in the United States and some other jurisdictions.
However, as you can read at the DeCSS information page, in most European countries DVD backup is legal. In fact, in countries such as Norway and Sweden you can legally backup anything that you own. If you do not require compatibility with a DVD player, consider encoding your videos in the Ogg Theora format.
Other free video formats:
- Dirac (another free video format in development)
Desktop publishing and graphics
- OpenDocument - This group of office document formats is seen as an excellent alternative to proprietary formats such as those used by Microsoft Office and is gaining widespread support in open-source office suites. OpenDocument recently became an International standard - ISO/IEC 26300. More information can be found on the ODF Alliance website.
- Scalable Vector Graphics (SVG) - SVG is a vector graphics format developed by the World Wide Web Consortium (W3C), which is responsible for major Web standards such as HTML, CSS and PNG. SVG is recommended as an alternative to proprietary vector graphics formats such as Adobe Illustrator (AI). A list of design tools which support this format is available. For more information, see the W3C's SVG pages.
Scribus is also a good alternative for desktop publishing.
General multimedia
Other multimedia format types are subject to legal restrictions.
Flash
There are several projects working to create a free implementation of Macromedia Flash, so that people can view Flash animations without resorting to non-free software:
Other
Other popular formats are subject to restrictions in some jurisdictions.
Java
Free implementation of Java is ongoing in many places, including GCJ, GNU Classpath, gcjwebplugin and the new Apache Harmony. Together they aim to provide a full Java platform as Free software. Current implementations are already being used to run OpenOffice.org 2's Java components, the Eclipse IDE and many other applications. Sun has recently announced that future versions of Java will be licenced under the GPL.
Additional Resources
- Wikipedia article on open formats - http://en.wikipedia.org/wiki/Open_format
- OpenFormats.org - http://www.openformats.org
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