MEDIA RELATED FILE TYPES Data Everything on your computer is a form of data or information and is ultimately reduced to a binary language of ones and zeros. If all data stayed as ones and zeros the information would be overwhelming in size. This raw data can be expressed more efficiently with the use of mathematical equations. Each codec (definition below) uses different equations for specific types of information. File Type/Format A file type mostly refers to a container or wrapper that stores different types of data. It also dictates what application(s) handle the file. For example, the file type/format JPEG labeled filename.jpeg can be opened on the web but will not open with audio software such as Adobe Audition. Each platform, such as the web, DVD, or mobile technology supports only select file types. Pixel A single unit of measurement used in rasterized graphics (definition below). A pixel is like a single dot in an image. Images, videos, websites, computer monitors and even flat screen televisions use pixels and each supports a limited amount of pixels. Bits The raw data, the ones and zeros, of all files. Could be considered the binary building blocks. Bit Depth The amount of bits found in a single unit of measurement such as a pixel for graphics or a sample for audio. For example, a 1-bit pixel can be only black or white (0 or 1), 2-bit images can support 4 colors (00, 01, 10, or 11), 4-bit images can support 16 colors, and 8-bit images support 256 colors. Most common bit depths found in technology today range from 8-bits to 64-bits. Color Space In graphics, colors are combined or mixed to create a spectrum of colors. The most common color spaces are RGB and CMYK (definitions below). Each color/color channel has its own bit depth, for example, some software will refer to 24-bit image as an 8-bit RGB image (8-bits for red + 8-bits for green + 8-bits for blue = 24 bits). Each color channel will have a separate value ranging from 1 to 256, for RGB there will be 3 different numbers whereas CMYK will have 4. RGB The color space used in nearly all electronic technology made up of red, green, and blue. CMYK The color space used in offset print technology based on the colors cyan, magenta, yellow, and black. Layers Nearly all graphics and audio software is based on the stacking of layers, also referred to as a composite. Similar to traditional image composites like collages or paintings, most graphics software treats the top layer as the front. Layers in software 2012 Adobe Foundation 1
are stacked, may be reordered, and can even interact with each other to create advanced composites. Alpha or Alpha Channel Also referred to as transparency, an Alpha is essentially invisible pixels. Found in video, still images, animation, and interactive media, this information allows for vast amounts of flexibility in combining layers from different sources. Codec A codec refers to a compressor and a de-compressor. All data must be wrapped up and unwrapped codecs act as the algorithm or equation (mathematical and visual) and are used to compress a file, making it more usable in a variety of production scenarios. It is important to distinguish between a file format and a codec. A codec performs the encoding and decoding of the raw data while the data itself is stored in a file. Some codecs are versatile, while others are known to be best for specific situations. Compression The process of reducing the size of files. image and data compression is combined together to analyze redundancies, then, usually controlled by the user, an ideal threshold is achieved where there is an optimized balance between quality and file size. Lossless A term used to describe a type of compression where there is no loss, usually meaning data compression without image compression or compromising quality. Vector A translation of graphics where images are reduced to paths and shapes therefore rendered as math and not pixels. Because they are not based in pixels (rasterized), vector graphics are infinitely scalable and small in file size. Vector graphics are mostly used to design crisp imagery like a logo built in Adobe Illustrator. Rasterized Graphics A raster is a grid of and Y and, in this case, a grid of pixels. Rasterized Graphics are still or moving images captured, for example, with a scanner or digital camera. They are usually larger in file size than vector graphics and cannot be scaled without some loss of information or resolution. Anti Aliasing Edge pixels in graphics like in an image of red shape on a green background, can result in aliasing, an inaccurate representation of the edge where it is jagged and not smooth. Anti aliasing gives the edges a more smooth appearance. Project Files A project file is a file that stores active data about projects like a timeline in Premiere or a project in After Effects. Some applications like Photoshop, Illustrator, Flash and Acrobat don t use project files because they store everything in one file like a PSD, AI, or PDF; this includes the content and the information about formatting. Applications like Premiere, Soundbooth, InDesign and Encore do not attempt to manage all your source files and instead just create a project file that s used as a recipe to describe how to display all your source media. This means that for a project to function properly, you must maintain links to the source media. 2012 Adobe Foundation 2
Image Files Type of file General use Compression Vector Alpha Layered JPG or JPEG TIFF GIF, PNG, TGA PSD RAW EPS AI Probably the most common of all file types used throughout production, but because of the compression and limitations it should mainly be used as a final output to the web or mobile device, not as a source file in high resolution works. Mostly used as a high-resolution source file in video, print, and web productions, but rarely found on the web due to its high file size. All 3 are very common on the web and TGA/ PNG is often used in videos as a sequence of image files with an alpha channel. A PSD is the basis of Photoshop. A versatile production file that contains all layers and editable adjustments that can be accessed via many Adobe applications including Premiere and After Effects. A fairly new format, now popular as the standard in high quality photography and digital cameras. The only limitation is its massive file size. A multilayered vector file used in print and as a part of most productions that require crisp designs and scale-able image sizes. Not used in photography as it supports only vector data. Much like a PSD, native to Illustrator, an AI is the basis of vector projects and is supported by most Adobe applications, notably Flash and InDesign. Light None None None None 2012 Adobe Foundation 3
Audio Files Type of file General use Compression Mac/PC WAVE or WAV AIFF or AIF MP3 MP4 and M4A MIDI or MID Video Files A commonly used file type originally created only for windows computers but now also supported by Mac. Wav makes a great file type for use in audio software but not ideal for the web. An uncompressed file type much like a WAV but developed by apple for use primarily on the Mac. An MP3 (MPEG Layer-3) has become one of the most popular formats for storing music. Its heavy compression is done by eliminating inaudible frequencies and makes it ideal for the web and for consumer music but not ideal for use in software. MP4 and M4A refer to MPEG 4 Audio, the successor to MP3. In most cases, there are no significant differences between the two. MIDI stands for Musical Instrument Digital Interface. A protocol developed as a way to contain musical information like pitch, velocity, and sustain without storing recorded sounds. MIDI information is used to tell a musical synthesizer what notes to play and how to play them. Light Light None Type of file General use Compression Alpha MOV or QT AVI and WMV MPEG or MPG FLV 3GP, 3GPP, 3G2 Originally developed by Apple, a QuickTime file is probably the most common of all video file types used throughout productions. It s ideal for use in software, but can support several codecs that also makes it useful on the web. video formats created for the Windows platform. Windows Media is also a good format for software, but is not great for the web and generally limited to PC only. MPEG refers to a moving version of JPEG (known originally as Motion JPEG). There are many versions of MPEG, from MPEG-1 to MPEG-4. MPEG is not an ideal production format but makes a great format for finishing DVD s. Flash Video is a newer format and has set many new standards for video on the web. Its heavy compression makes very compact files that you ll find on sites like YouTube.com or Blip.tv. It s also the native format to Adobe Flash and is therefore useful in interactive graphics. An obscure format used mainly with mobile phones. Varies Varies Medium to Medium to Mac Limited to the animation codec Limited to the animation codec 2012 Adobe Foundation 4
Document files Type of file TT and RTF DOC or DOC LS and CSV PDF HTML or HTM TTF General use Just about the most basic of all, a TT (text) file or an RTF (rich text) file contains only text in its most basic form. Developed by Microsoft as the standard for Word and now as a DOC (open DOC) is supported by other software. A file used in spreadsheet software like Microsoft Excel. The Portable Document File (PDF) was developed by Adobe as a standard for forms and published documents. A PDF is also known for its security control and permissions. Makes a great format for legal docs and docs that incorporate images, fonts and text. HyperText Markup Language is the predominant language of the web and is where most web pages store content. It can also be used to describe layout, formatting, and functionality. A TTF is a True Type Font, a file format that contains a font that can be loaded to you system and used throughout most applications. 2012 Adobe Foundation 5