Multimedia File Formats
Published by Emil Abraham,
File Standards
File standards refer to established guidelines and specifications that define the structure, format, and encoding of files used in digital media. These standards ensure consistency and compatibility across different software applications, platforms, and devices.
In multimedia production, adherence to file standards is crucial for seamless data exchange, interoperability, and the preservation of data integrity.
Communication Protocols
Communication protocols are a set of rules and conventions that govern the exchange of data between devices or systems in a network.
In multimedia production, communication protocols play a vital role in facilitating the transfer of multimedia files between different components, such as cameras, computers, and servers. These protocols ensure that data is transmitted reliably and efficiently.
Compression
The development of new ways to compress audio and video signals is critical to the new digital multimedia age. Research in signal processing and coding for digital video has been key to the success of the MPEG-2 digital video compression standard, which allows the transmission of high-quality video and audio signals over limited bandwidth.
The technology conserves bandwidth by eliminating redundant information, such as backgrounds that do not change, thus reducing the amount of data storage or transmission required to reproduce video sequences.
Video compression will always be necessary for storage and transmission, even when enormous quantities of bandwidth are available. Experts see a future in which emphasis on content will create the next revolution in multimedia technology, enhancing human communications in every context by empowering people to convey complex ideas simply and easily through digital storytelling.
Data compression is the process of encoding data using a representation that reduces the overall size of data. This reduction is possible when the original dataset contains some type of redundancy. Data compression, also called compaction, the process of reducing the amount of data needed for the storage or transmission of a given piece of information, typically by the use of encoding techniques. Multimedia compression is employing tools and techniques in order to reduce the file size of various media formats.
Decompression is the process of restoring compressed data to its original form. Data decompression is required in almost all cases of compressed data, including lossy and lossless. compression. Decompression is widely used in data communications, multimedia, audio, video and file transmissions.
The need of lossless compression techniques is required in many applications such in medical data there were no loss of information.
Lossy vs. Lossless Compression
Lossless compression reduces storage space without degrading image and time needed for computational will also decrease. The Lossless image compression algorithm for different application like medical image, Lossless inter frame coding for MRI image, Ultra sound image, Capsule Endoscopy (CE).
In information technology, lossy compression or irreversible compression is the class of data encoding methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size for storing, handling, and transmitting content.
The following is an outline of current file formats used for the production and delivery of multimedia.
Authoring vs. Editing Tools
An authoring tool assists you in creating digital content. The tool could be something as simple as Google documents, or as complex as a video production suite.
The basic tools set for building multimedia project contains one or more authoring systems and various editing applications for text, images, sound, and motion video. A few additional applications are also useful for capturing images from the screen, translating file formats and tools for the making multimedia production easier.
In the context of images, a authoring commonly refers to software that helps to create digital drawings and pictures. While an editing tool works on an existing image to alter, combine, modify or enhance it. The main job of authoring tool is to make developing content more efficiently, and open up possibilities that would be infeasible, or too time consuming to develop without a dedicated tool.
Image authoring tools: Adobe Illustrator, CoreDraw, Adobe Photoshop, GIMP
Image editing tools: Adobe Photoshop, Adobe Lightroom, PicMonkey, Pixlr, Snapseed.
File Formats
(i) Text Formats
(a) RTF (Rich Text Format)
RTF is a proprietary document file format with published specification developed by Microsoft Corporation in 1987 for Microsoft products and for cross-platform document interchange.
(b) Plain text
Plain text files can be opened, read, and edited with most text editors. Examples include Notepad (Windows), edit (DOS), ed, emacs, vi, vim, Gedit or nano (Unix, Linux), SimpleText (Mac OS), or TextEdit (Mac OS X). Other computer programs are also capable of reading and importing plain text. Plain text is the original and ever popular method of conveying e-mail. HTML formatted e-mail messages often include an automatically-generated plain text copy as well, for compatibility reasons.
(ii) Image Formats
(a) TIFF (Tagged Image File Format)
This format is common in desktop publishing world, and almost all software packages support it. Recent versions of TIFF allow for image compression, and the format is handy for moving large files between computers.
(b) BMP (Bitmap)
This format came into use with Windows 3.1. It is uncompressed and can be quite large. For this reason, BMP is seldom used for the large or high- resolution images.
(c) DIB (Device Independent Bitmap)
This format is similar to BMP, allows files to be displayed on a variety of devices.
(d) GIF (Graphics Interchange format)
GIF is a compressed image format developed by CompuServe, an online information service. Most computer colour images and backgrounds are GIF files. This compact file format is ideal for graphics that use only few colours, and it was once the most popular format for online colour photos. The GIF format uses an 8-bit Colour Look Up Table to identify its colour values. This format is widely supported by several shareware viewers and converters.
(e) JPEG (Joint Photographic Experts Group)
This format was designed for maximum image compression. JPEG uses loosy compression, which refers to a compression scheme that actually looses some of the data needed to reconstruct the image. It works well on photographs, naturalistic artwork, and similar material but does not work well on lettering, simple cartoons, or live drawings. The rationale behind loosy compression is that the human eye does not miss the lost information.
(f) TGA (Tagra)
This was the first popular format for high-resolution images. The name comes from the original Targa board, the first true-colour video board. Most video-capture boards support TGA, as do most high-end paint programs.
(g) PNG (Portable Network Graphics)
An extensible file format for the loss less, portable, well compressed storage of raster images. PNG provides a patent free replacement for GIF and can also replace many common uses of TIFF. PNG is designed to work well in online viewing applications, such as the worldwide web, so it is fully streamable with a progressive display option. PNG files are commonly used to store web graphics, digital photographs, and images with transparent backgrounds.
(iii) Digital Audio File Formats
(a) WAV (Waveform Audio File Format)
The most popular audio file format used mainly in windows for storing uncompressed sound files. It can be converted to other file formats like MP3to reduce the file size.
(b) MP3 (MPEG Layer-3 Format)
MPEG Layer-3 format is the most popular format downloading and storing music. The MP3 files are compressed to roughly one-tenth the size of an equivalent WAV file.
(c) OGG
A free, open source container format that can be compared to MP3 files in terms of quality.
(d) AU
It is a standard audio file format used by Sun, Unix and Java. The audio in AU file format can be compressed.
(e) AIFF (Audio Interchange File Format)
A standard audio file format used by Apple which is like a WAV file for the Mac.
(f) WMA (Windows Media Audio)
It is a popular windows media audio format owned by Microsoft and designed with Digital Right Management (DRM) abilities for copy protection.
(g) RA (Real Audio Format)
Real Audio format is designed for streaming audio over the Internet.
The digital audio resources are usually stored as a computer file in computer‟s hard drive or CD-Rom or DVD. There are multitudes of audio file formats, but the most common formats are wave files (.WAV) and MPEG Layer-3 files (.MP3), WMA and RA. Following are the commonly used digital audio file formats (Rajashekharan & Nafala, 2009).
(iv) Digital Video File Formats
(a) AVI (Audio/Video Interleave)
AVI is the file format used by Video for Windows, one of three video technologies used on personal computers. In AVI, picture and sound elements are stored in alternate interleaved chunks in the file.
(b) MPEG (Moving Picture Experts Group)
MPEG is a group of people that meet under the International Standards Organization (ISO) to generate standards for digital video and audio compression. Established in 1988, the group has produced MPEG-1, the standard on which Video CD and MP3 are based, MPEG-2, the standard on which such products as Digital Television set top boxes and DVD are based, MPEG-4, the standard for multimedia for the fixed and mobile web and MPEG-7, the standard for description and search of audio and visual content. Work on the new standard MPEG-21 "Multimedia Framework" has started in June2000. Technically speaking MPEG is not a storage format but standards for digital video and audio compression.
A video file format is a standard for encoding digital video, audio and some auxiliary information into a file. In contrast to audio and image formats, most video file formats allow a variety of codecs, both audio and video to be used.
Layers
In graphics software, a layer is the term used to describe the different levels at which you can place an object or image file. In the program you can stack, merge or define layers when creating a digital image. Layers can be partially obscured allowing portions of images within a layer to be hidden or shown in a translucent manner within another image, or you can use layers to combine two or more images into a single digital image. For the purpose of editing, working with layers allows you to go back and make changes within a layer as you work.
Layers are used in digital image editing to separate different elements of an image. A layer can be compared to a transparency on which imaging effects or images are applied and placed over or under an image. Today they are an integral feature of image editors.
Colour systems
There are two major colour systems in the digital and print design industries: the RGB color system and the CMYK color system.
In short:
- RGB = Red, Green, Blue. Use for digital designs.
- CMYK = Cyan, Magenta, Yellow, and Key. Use for anything printed.
RGB stands for Red, Green, and Blue. It’s used exclusively in the digital design industry because it represents the same colors used in computer screens, TV screens, as well as mobile device screens.
It’s an additive color system which means that the primary colors are added together in various combinations to produce a much wider spectrum of colors. These colors are produced by blending light itself by superimposing the red, green, and blue light beam. Without any intensity, each of those colors will be perceived as black, while full intensity will make them appear white.
It’s also worth mentioning that different intensities of each color will produce the hue of a particular color. The resulting color will also appear more or less saturated depending on the difference between the most and the least intensive color.
As a general rule of thumb, the RGB color system should be used only in digital designs, most commonly when designing for the web. This includes designing websites and imagery and graphics for use on websites and social media.
CMYK stands for Cyan, Magenta, Yellow, and Key (Black). Black, in this case, is referred to as key because it is used in the key plate which is responsible for adding the contrast and the detail for the final image.
The CMYK color system is a subtractive colour system and is most commonly referred to as the four-color process because it uses four different colors to produce different hues. The black color here is used because the other three colors combined cannot produce a fully saturated black.
In subtractive color method, a new color is created by combining colored media such as paints or ink that absorb (or subtract) some parts of the color spectrum of light and reflect the others back to the eye. Subtractive color is the process used to create color in printing. The printed page is made up of tiny halftone dots of three primary colors, cyan, magenta and yellow (CMY).
CMYK is the recommended color system for any material that will be printed. This includes business cards, brochures, letterheads, and any other business collateral.
Brightness refers to the absolute value of colors (tones) lightness/darkness.
Increasing brightness of an image will light out all colors so the original light ones will become up to white.
Reversely, decreasing brightness will darken all colors so the original shaded ones will become up to black.
Contrast is the distinction between lighter and darker areas of an image, and it rerefersto making more obvious the objects or details within an image.
Increasing contrast on an image will increase the difference between light and dark areas so light areas will become lighter and dark areas will become darker.
Reversely, decreasing the contrast will make lighter and darker areas stay approximately the same but the overall image becomes more "flat" and starts looking as if it were "washed out".
Slicing: If the file is large it will take a long time to load, especially for users with a slower connection. You can reduce the file size with compression but you can only go so far before image quality will begin to suffer.
The solution to your problem is to use image slicing – it will cut the image into smaller sections. These images will be saved as a separate file and optimized using the Save for Web command.
In addition, Photoshop creates the HTML or CSS necessary to display the sliced image. When used in a web page, each image will be reassembled in the browser using the HTML or CSS mentioned earlier to create a smooth result.
Contrast ratio: The ratio of the brightest white to the darkest black on a TV or computer monitor. The larger the number, the greater the extremes; for example, car headlights can appear brilliant next to the pitch black of the night sky. Contrast ratio is an important criterion in screen quality.
The ratio is derived by the brightest luminance divided by the darkest luminance in candelas per square meter (cd/m2). [base unit of luminous intensity] For example, if white is 98 cd/m2 and black is 0.02, the ratio is 4900:1.
Aspect ratio: The aspect ratio of an image describes the proportional relationship between its width and its height. It is commonly expressed as two numbers separated by a colon, as in 16:9.
The most common aspect ratios used today in the presentation of films in cinemas are 1.85:1 and 2.39:1. Two common videographic aspect ratios are 4:3 (1.3:1), the universal video format of the 20th century, and 16:9 (1.7:1), universal for high-definition television and European digital television. Other cinema and video aspect ratios exist, but are used infrequently.
In still camera photography, the most common aspect ratios are 4:3, 3:2, and more recently found in consumer cameras, 16:9. Other aspect ratios, such as 5:3, 5:4, and 1:1 (square format), are used in photography as well, particularly in medium format and large format.
Greyscale: Grayscale is a range of shades of gray without apparent color. The darkest possible shade is black, which is the total absence of transmitted or reflected light. The lightest possible shade is white, the total transmission or reflection of light at all visible wavelengths.
Filters: Filters are integral image processing tools used to modify or enhance images by applying various effects. They come in different types, including color filters for adjusting tones and hues, blur filters for softening edges, sharpen filters for enhancing details, and noise reduction filters for reducing unwanted graininess. These tools find applications in photography, where they are used to create artistic effects or correct imperfections, as well as in graphic design to enhance digital artwork. Adobe Photoshop, GIMP, and Lightroom are examples of software that offer a wide range of filter options for image manipulation.
Blending Tools: Blending tools play a crucial role in seamlessly combining different elements of an image or graphic. They encompass various techniques such as opacity blending, which adjusts the transparency of layers for smooth transitions, blend modes that alter how layers interact with each other, and gradient blending to blend colors smoothly across an image. These tools are extensively used in photo editing for merging multiple images or layers and in digital art to create depth and texture. Adobe Photoshop, Procreate, and Corel Painter are popular software that provides robust blending capabilities.
Image Enhancing & Designing Techniques: Image enhancing and designing techniques encompass a broad spectrum of methods aimed at improving the visual quality and aesthetics of images. These techniques include color correction for adjusting color balance and saturation, retouching for removing imperfections, adding effects like shadows and glows, and compositing to combine multiple images or elements. They find applications in various domains such as advertising, where images are enhanced to create visually appealing advertisements, and web design, where designers use these techniques to create engaging website visuals. Software like Adobe Photoshop, Lightroom, and Affinity Photo offer powerful tools for implementing these techniques effectively.