BitComet Support Team's BLOG

OGG is a bitstream container format for efficient streaming and file compression. It was created in the process of developing a set of components for the coding and decoding of multimedia content which could be both freely available and freely re-implementable in software.

OGG includes a number of separate independent open source codecs for both audio and video. Due to the fact that this format is patent-free and fully open ogg's various codecs have been incorporated into a number of different free and commercial media players.

Its name originates from jargon that means to do something forcefully, possibly without consideration of the drain on future resources. At its inception the Ogg project was thought to be somewhat ambitious given the power of the PC hardware of the time.

You can use mpcstar to open files with this suffix. http://www.mpcstar.com/

Encapsulated PostScript, or EPS, is a DSC-conforming PostScript document with additional restrictions intended to make EPS files usable as a graphics file format. In other words, EPS files are more-or-less self-contained, reasonably predictable PostScript documents that describe an image or drawing, that can be placed within another PostScript document.

At a minimum, an EPS file contains a BoundingBox DSC comment, describing the rectangle containing the image described by the EPS file. Applications can use this information to lay out the page, even if they are unable to directly render the PostScript inside.

EPS, together with DSC's Open Structuring Conventions, form the basis of early versions of the Adobe Illustrator Artwork file format.

Eclipse Modeling Framework (EMF) is an Eclipse-based modeling framework and code generation facility for building tools and other applications based on a structured data model. From a model specification described in XMI, EMF provides tools and runtime support to produce a set of Java classes for the model, a set of adapter classes that enable viewing and command-based editing of the model, and a basic editor. Models can be specified using annotated Java, UML, XML documents, or modeling tools like Rational Rose, then imported into EMF. Most important of all, EMF provides the foundation for interoperability with other EMF-based tools and applications.

JPEG stands for Joint Photographic Experts Group. It is a standard method of compressing photographic images. We also call JPEG the file format which employs this compression.

The file extensions for this format are .JPEG, .JFIF, .JPG, OR .JPE although .JPG is the most common on all platforms.

JPEG/JFIF is mostly used for storing and transmitting photographs on the World Wide Web, but not as well suited for line drawings and other textual or iconic graphics because its compression method performs badly on these types of images.

Some facts about JPEG:

• JPEG is a well established standard with plenty of software available, including free software.
• JPEG is at its best on photographs and paintings of realistic scenes with smooth variations of tone and color.
• The ratios at which the downsampling can be done on JPEG are 4:4:4 (no downsampling), 4:2:2 (decimate by factor of 2 in horizontal direction), and most commonly 4:2:0 (decimate ......

JPEG 2000 is a wavelet-based image compression standard. It was created by the Joint Photographic Experts Group committee in the year 2000 with the intention of superseding their original discrete cosine transform-based JPEG standard (created about 1991). The standardized filename extension is .jp2 for ISO/IEC 15444-1 conforming files and .jpx for the extended part-2 specifications, published as ISO/IEC 15444-2, while the MIME type is image/jp2.

JPEG 2000 requires far greater decompression time than JPEG and allows more sophisticated progressive downloads, yet averages similar compression rates. JPEG 2000 becomes increasingly blurred with higher compression ratios rather than generating JPEG's "blocking and ringing" artifacts, complicating direct comparison of their respective compression rates. Images machine-judged to be of equivalent quality for both compression schemes often look better to humans in JPEG 2000 at low bitrates.

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PCD stands for Photo CD and means a high (actually the highest) resolution format for images on a CD. It was developed by Kodak. A PCD file contains five different resolution (ranging from low to high) of a slide or film negative. Due to it PCD is often used by many photographers and graphics professionals for high-end printed applications.

PCD files can be accessed in a variety of dimensions and color depths, which is quite handy, and the format is good at encoding and storing authentic color information. The PCD files are typically 4 to 6 MB in size and, therefore, take some time to transfer via the web.

Each PCD file contains five scans of the same image at the following resolutions:

192 x 128 - 73,728 bytes
384 x 256 - 294,912 bytes
768 x 512 - 1,179,648 bytes
1536 x 1024 - 4,784,128 bytes
3072 x 2048 - 19,070,976 bytes
6144 x 4096 - 75,694,080 bytes

The disadvantage is that not all CD-ROM drives can access Photo-CDs. ......

PCX is an image file format that uses a simple form of run-length encoding. It’s lossless. The ZSoft Corporation of Marietta, Georgia, USA developed it as the native file format for their PC Paintbrush graphics program, which used to be quite popular with early PCs’ users. Nowadays it has been largely replaced by GIF, JPEG and PNG which support better compression.

Because colors 0x00..0xc0 are compressed better than colors 0xc1..0xff, good palette sorting is important. It's usually (but not always) enough to move the most-common colors into palette positions 0x00..0xc0, and least-used to palette positions 0xc1..0xff. The complete algorithm for sorting the palette is to count how many times a color appears 63N+1 (for nonnegative integer N) in a row, as it's only possible in such cases to use unprefixed color values to improve compression, and move colors with higher count into indexes 0x00..0xc0, and all others to 0xc1..0xff. This is warranted to produce optimal ......

PICT(PCT,PIC) is a graphics file format introduced on the original Apple Macintosh computer as its standard metafile format. It allows the interchange of graphics (both bitmapped and vector), and some limited text support, between Mac applications, and was the native graphics format of the Quickdraw Manager.

The original version, PICT 1, was designed to be as compact as possible while describing vector graphics. To this end, it featured single byte opcodes, many of which embodied operations such as "do the previous operation again". As such it was quite memory efficient, but not very expandable. With the introduction of the Macintosh II and Colour Quickdraw, PICT was revised to version 2. This version featured 16-bit opcodes and numerous changes which enhanced its utility. PICT 1 opcodes were supported as a subset for backward compatibility.

Within a Mac application, any sequence of drawing operations could be simply recorded/encoded to the PICT......

PSD is Photoshop's native file format, sometimes it's called PDD. PSD or PDD is a widely accepted file format. PSD supports all available image modes (Bitmap, Grayscale, Duotone, Indexed Color, RGB, CMYK, Lab, and Multichannel).

The PSD format is extremely useful as it can support duotones, clipping paths and channels. Moreover, PSD offers a unique feature - it supports layers while every other format must be flattened on export. Any program that supports PSDs directly can then leverage this layer information. Saving as layered images is quite handy as it allows to edit different parts of an image at a later date far easier.

PostScript (PS) is a page description language and programming language used primarily in the electronic and desktop publishing areas.