- Mac change default app for file type how to#
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However, the GIF patent expired in the US in mid-2003, and worldwide in mid-2004.ĭifferent operating systems have traditionally taken different approaches to determining a particular file's format, with each approach having its own advantages and disadvantages. This has resulted in a significant decrease in the use of GIFs, and is partly responsible for the development of the alternative PNG format. For example, using compression with the GIF file format requires the use of a patented algorithm, and though the patent owner did not initially enforce their patent, they later began collecting royalty fees. Although patents for file formats are not directly permitted under US law, some formats encode data using patented algorithms.
Patent law, rather than copyright, is more often used to protect a file format.
Both strategies require significant time, money, or both therefore, file formats with publicly available specifications tend to be supported by more programs. The latter approach is possible only when a formal specification document exists.
Mac change default app for file type how to#
If the developer of a format doesn't publish free specifications, another developer looking to utilize that kind of file must either reverse engineer the file to find out how to read it or acquire the specification document from the format's developers for a fee and by signing a non-disclosure agreement. Not all formats have freely available specification documents, partly because some developers view their specification documents as trade secrets, and partly because other developers never author a formal specification document, letting precedent set by other already existing programs that use the format define the format via how these existing programs use it. 4.1 Unstructured formats (raw memory dumps)įile formats often have a published specification describing the encoding method and enabling testing of program intended functionality.3.3.8 File content based format identification.3.3.5 PRONOM unique identifiers (PUIDs).
Mac change default app for file type mac os x#
3.3.2 Mac OS X uniform type identifiers (UTIs).
Mac change default app for file type software#
Some file formats, such as HTML, scalable vector graphics, and the source code of computer software are text files with defined syntaxes that allow them to be used for specific purposes. A text file can contain any stream of characters, including possible control characters, and is encoded in one of various character encoding schemes. Other file formats, however, are designed for storage of several different types of data: the Ogg format can act as a container for different types of multimedia including any combination of audio and video, with or without text (such as subtitles), and metadata. Some file formats are designed for very particular types of data: PNG files, for example, store bitmapped images using lossless data compression. File formats may be either proprietary or free and may be either unpublished or open. It specifies how bits are used to encode information in a digital storage medium. A file format is a standard way that information is encoded for storage in a computer file.
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