Related Research Articles
In computer graphics, alpha compositing or alpha blending is the process of combining one image with a background to create the appearance of partial or full transparency. It is often useful to render picture elements (pixels) in separate passes or layers and then combine the resulting 2D images into a single, final image called the composite. Compositing is used extensively in film when combining computer-rendered image elements with live footage. Alpha blending is also used in 2D computer graphics to put rasterized foreground elements over a background.
JPEG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality. Since its introduction in 1992, JPEG has been the most widely used image compression standard in the world, and the most widely used digital image format, with several billion JPEG images produced every day as of 2015.
Portable Network Graphics is a raster-graphics file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF)—unofficially, the initials PNG stood for the recursive acronym "PNG's not GIF".
The BMP file format or bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device, especially on Microsoft Windows and OS/2 operating systems.
RGBA stands for red green blue alpha. While it is sometimes described as a color space, it is actually a three-channel RGB color model supplemented with a fourth alpha channel. Alpha indicates how opaque each pixel is and allows an image to be combined over others using alpha compositing, with transparent areas and anti-aliasing of the edges of opaque regions.
Smacker video is a video file format developed by Epic Games Tools, and primarily used for full-motion video in video games. Smacker uses an adaptive 8-bit RGB palette. RAD's format for video at higher color depths is Bink Video. The Smacker format specifies a container format, a video compression format, and an audio compression format. Since its release in 1994, Smacker has been used in over 2300 games. Blizzard used this format for the cinematic videos seen in its games Warcraft II, StarCraft and Diablo I.
QuickTime Animation format is a video compression format and codec created by Apple Computer to enable playback of RGB video in real time without expensive hardware. It is generally found in the QuickTime container with the FourCC 'rle '. It can perform either lossless or lossy compression and is one of the few video codecs that supports an alpha channel. Supported color depths are 1-bit (monochrome), 15-bit RGB, 24-bit RGB, 32-bit ARGB, as well as palettized RGB. As a result of reverse-engineering of the format, a decoder is implemented in XAnim as well as an encoder and decoder in libavcodec.
S3 Texture Compression (S3TC) is a group of related lossy texture compression algorithms originally developed by Iourcha et al. of S3 Graphics, Ltd. for use in their Savage 3D computer graphics accelerator. The method of compression is strikingly similar to the previously published Color Cell Compression, which is in turn an adaptation of Block Truncation Coding published in the late 1970s. Unlike some image compression algorithms, S3TC's fixed-rate data compression coupled with the single memory access made it well-suited for use in compressing textures in hardware-accelerated 3D computer graphics. Its subsequent inclusion in Microsoft's DirectX 6.0 and OpenGL 1.3 led to widespread adoption of the technology among hardware and software makers. While S3 Graphics is no longer a competitor in the graphics accelerator market, license fees have been levied and collected for the use of S3TC technology until October 2017, for example in game consoles and graphics cards. The wide use of S3TC has led to a de facto requirement for OpenGL drivers to support it, but the patent-encumbered status of S3TC presented a major obstacle to open source implementations, while implementation approaches which tried to avoid the patented parts existed.
FXT1 is a texture compression scheme for 3D graphics, invented by the hardware vendor 3dfx Interactive and offered as an open source rival standard to S3TC in September 1999, a year after S3TC had been adopted by Microsoft as part of DirectX. Limited vendor hardware support has been a barrier to its acceptance. Notably, despite being open source, FXT1 was not adopted by Nintendo for the GameCube, nor by Sony for the PlayStation 3, in both cases losing out to the established S3TC standard. Another possible reason for its lack of adoption is that the CC_MIXED mode probably infringes the S3TC patent.
Microsoft Video 1 or MS-CRAM is an early lossy video compression and decompression algorithm (codec) that was released with version 1.0 of Microsoft's Video for Windows in November 1992. It is based on MotiVE, a vector quantization codec which Microsoft licensed from Media Vision. In 1993, Media Vision marketed the Pro Movie Spectrum, an ISA board that captured video in both raw and MSV1 formats.
The Apple Icon Image format (.icns) is an icon format used in Apple Inc.'s macOS. It supports icons of 16 × 16, 32 × 32, 48 × 48, 128 × 128, 256 × 256, 512 × 512 points at 1x and 2x scale, with both 1- and 8-bit alpha channels and multiple image states. The fixed-size icons can be scaled by the operating system and displayed at any intermediate size.
Silicon Graphics Image (SGI) or the RGB file format is the native raster graphics file format for Silicon Graphics workstations. The format was invented by Paul Haeberli. It can be run-length encoded (RLE). FFmpeg and ImageMagick, among others, support this format.
JPEG XR is an image compression standard for continuous tone photographic images, based on the HD Photo specifications that Microsoft originally developed and patented. It supports both lossy and lossless compression, and is the preferred image format for Ecma-388 Open XML Paper Specification documents.
Texture compression is a specialized form of image compression designed for storing texture maps in 3D computer graphics rendering systems. Unlike conventional image compression algorithms, texture compression algorithms are optimized for random access.
PVRTC and PVRTC2 are a family of lossy, fixed-rate texture compression formats used in PowerVR's MBX, SGX and Rogue technologies. The PVRTC algorithm is documented in Simon Fenney's paper "Texture Compression using Low-Frequency Signal Modulation" that was presented at Graphics Hardware 2003.
CineForm Intermediate is an open source video codec developed for CineForm Inc by David Taylor, David Newman and Brian Schunck. On March 30, 2011, the company was acquired by GoPro which in particular wanted to use the 3D film capabilities of the CineForm 444 Codec for its 3D HERO System.
Adaptive scalable texture compression (ASTC) is a lossy block-based texture compression algorithm developed by Jørn Nystad et al. of ARM Ltd. and AMD.
Apple Video is a lossy video compression and decompression algorithm (codec) developed by Apple Inc. and first released as part of QuickTime 1.0 in 1991. The codec is also known as QuickTime Video, by its FourCC RPZA and the name Road Pizza. When used in the AVI container, the FourCC AZPR is also used.
QuickTime Graphics is a lossy video compression and decompression algorithm (codec) developed by Apple Inc. and first released as part of QuickTime 1.x in the early 1990s. The codec is also known by the name Apple Graphics and its FourCC SMC. The codec operates on 8-bit palettized RGB data. The bit-stream format of QuickTime Graphics has been reverse-engineered and a decoder has been implemented in the projects XAnim and libavcodec.
The Quite OK Image Format (QOI) is a specification for lossless image compression of 24-bit or 32-bit color raster (bitmapped) images, invented by Dominic Szablewski and first announced on 24 November 2021.
References
- ↑ iPACKMAN: High-Quality, Low-Complexity Textures Compression for Mobile Phones -- Jacob Ström (Ericsson Research), Tomas Akeinine-Möller (Lund University)
- ↑ PACKMAN: Texture Compression for Mobile Phones -- Jacob Ström (Ericsson Research), Tomas Akeinine-Möller (Lund University).
- 1 2 "Sample code for handling alpha channels in ETC1 from ARM". Archived from the original on 2011-10-27. Retrieved 2011-11-03.
- ↑ OES_compressed_ETC1_RGB8_texture, A description of the ETC1- compression algorithm and texture format in OpenGL ES extension registry
- ↑ Release notes for Android 2.2 Archived 2010-10-11 at the Wayback Machine , (Froyo)
- ↑ Paper about ETC2: Texture Compression using Invalid Combinations
- ↑ "OpenGL ES Version 3.0 Specification" (PDF). Archived from the original (PDF) on 2016-03-06. Retrieved 2012-08-07.
- ↑ OpenGL Version 4.3 Specification
- ↑ Ericsson ETCPACK on Github