De facto standard in the context of "Video file format"

A calendar date is a reference to a particular day, represented within a calendar system, enabling a specific day to be unambiguously identified. Simple math can be performed between dates; commonly, the number of days between two dates may be calculated, e.g., "25 December 2025" is ten days after "15 December 2025". The date of a particular event depends on the time zone used to record it. For example, the air attack on Pearl Harbor that began at 7:48 a.m. local Hawaiian time (HST) on 7 December 1941 is recorded equally as having happened on 8 December at 3:18 a.m. Japan Standard Time (JST).

A particular day may be assigned a different nominal date according to the calendar used. The de facto standard for recording dates worldwide is the Gregorian calendar, the world's most widely used civil calendar. Many cultures use religious calendars such as the Gregorian (Western Christendom, AD), the Julian calendar (Eastern Christendom, AD), Hebrew calendar (Judaism, AM), the Hijri calendars (Islam, AH), or any other of the many calendars used around the world. Regnal calendars (that record a date in terms of years since the beginning of the monarch's reign) are also used in some places, for particular purposes.

The civil calendar is the calendar, or possibly one of several calendars, used within a country for civil, official, or administrative purposes. The civil calendar is almost always used for general purposes by people and private organizations.

The most widespread civil calendar and de facto international standard is the Gregorian calendar. Although that calendar was first declared by Pope Gregory XIII to be used in Catholic countries in 1582, it has since been adopted, as a matter of convenience, by many secular and non-Christian countries, although some countries use other calendars.

In typography, the point is the smallest unit of measure. It is used for measuring font size, leading, and other items on a printed page. The size of the point has varied throughout printing's history. Since the 18th century, the size of a point has been between 0.18 and 0.4 millimeters. Following the advent of desktop publishing in the 1980s and 1990s, digital printing has largely supplanted the letterpress printing and has established the desktop publishing (DTP) point as the de facto standard. The DTP point is defined as 1⁄72 of an inch (or exactly 0.3527 mm) and, as with earlier American point sizes, is considered to be 1⁄12 of a pica.

In metal type, the point size of a font describes the height of the metal body on which that font's characters were cast. In digital type, letters of a computer font are designed around an imaginary space called an em square. When a point size of a font is specified, the font is scaled so that its em square has a side length of that particular length in points. Although the letters of a font usually fit within the font's em square, there is not necessarily any size relationship between the two, so the point size does not necessarily correspond to any measurement of the size of the letters on the printed page.

QWERTY (/ˈkwɜːrti/ KWUR-tee) is a keyboard layout for Latin-script alphabets; the name comes from the order of the first six keys on the top letter row of the keyboard: QWERTY. The design evolved for the quick typing of English on typewriters.

The QWERTY design is based on a layout included on the Sholes and Glidden typewriter sold by E. Remington and Sons from 1874. The layout became popular with the success of the Remington No. 2 of 1878 and remains in widespread use as a de facto standard on computers, as of 2025. Two prominent alternatives, Dvorak and Colemak, have been developed. In Europe, two types of modified layouts, QWERTZ and AZERTY, are used predominantly for German and French, respectively.

A video coding format (or sometimes video compression format) is an encoded format of digital video content, such as in a data file or bitstream. It typically uses a standardized video compression algorithm, most commonly based on discrete cosine transform (DCT) coding and motion compensation. A computer software or hardware component that compresses or decompresses a specific video coding format is a video codec.

Some video coding formats are documented by a detailed technical specification document known as a video coding specification. Some such specifications are written and approved by standardization organizations as technical standards, and are thus known as a video coding standard. There are de facto standards and formal standards.

An audio coding format (or sometimes audio compression format) is a encoded format of digital audio, such as in digital television, digital radio and in audio and video files. Examples of audio coding formats include MP3, AAC, Vorbis, FLAC, and Opus. A specific software or hardware implementation capable of audio compression and decompression to/from a specific audio coding format is called an audio codec; an example of an audio codec is LAME, which is one of several different codecs which implements encoding and decoding audio in the MP3 audio coding format in software.

Some audio coding formats are documented by a detailed technical specification document known as an audio coding specification. Some such specifications are written and approved by standardization organizations as technical standards, and are thus known as an audio coding standard. The term "standard" is also sometimes used for de facto standards as well as formal standards.