SWF format - Adobe Flash

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SWF (Adobe Flash)

Adobe Flash, or simply Flash, refers to both the Adobe Flash Player, and to the Adobe Flash Professional multimedia authoring program. Adobe Flash Professional is used to create content for the Adobe Engagement Platform (such as web applications, games and movies, and content for mobile phones and other embedded devices). The Flash Player, developed and distributed by Adobe Systems (which acquired Macromedia in a merger that was finalized in December 2005), is a client application available in most common web browsers. It features support for vector and raster graphics, a scripting language called ActionScript and bi-directional streaming of audio and video. There are also versions of the Flash Player for mobile phones and other non-PC devices.

Strictly speaking, Adobe Flash Professional is an integrated development environment (IDE) while Flash Player is a virtual machine used to run, or parse, the Flash files. But in contemporary colloquial terms "Flash" can refer to the authoring environment, the player, or the application files.

Since its introduction in 1996, Flash technology has become a popular method for adding animation and interactivity to web pages; several software products, systems, and devices are able to create or display Flash. Flash is commonly used to create animation, advertisements, various web-page components, to integrate video into web pages, and more recently, to develop rich Internet applications.

The Flash files, traditionally called "Flash movies" or "Flash games", have a .swf file extension and may be an object of a web page, strictly "played" in a standalone Flash Player, or incorporated into a Projector, a self-executing Flash movie with the .exe extension in Windows. Flash Video files have a .FLV file extension and are utilized from within .swf files.

Programming language

Initially focused on animation, early versions of Flash content offered few interactivity features and thus had very limited scripting capability.

More recent versions include ActionScript, a scripting language which has syntax similar to JavaScript and so supporting JSON syntax (a variation on ECMA), but a much different programming framework and set of class libraries. ActionScript is used to create almost all of the interactivity (buttons, text entry fields, pick lists) seen in many Flash applications.

New versions of the Flash Player and authoring tool have striven to improve on scripting capabilities. Flash MX 2004 introduced ActionScript 2.0, a scripting programming language more suited to the development of Flash applications. It's often possible to save a lot of time by scripting something rather than animating it, which usually also retains a higher level of editability.

Of late, the Flash libraries are being used with the XML capabilities of the browser to render rich content in the browser. Since Flash provides more comprehensive support for vector graphics than the browser and because it provides a scripting language geared towards interactive animations, it is being considered a viable addition to the capabilities of a browser. This technology, which is currently in its nascent stage, is known as Asynchronous Flash and XML, much like AJAX, but with possibly greater potential.

Content protection

Many times, Flash authors will decide that while they desire the advantages that Flash affords them in the areas of animation and interactivity, they do not wish to expose their images and/or code to the world. However, once an .swf file is saved locally, it may then quite easily be decompiled into its source code and assets. Some decompilers are capable of nearly full reconstruction of the original source file, down to the actual code that was used during creation.

In opposition to the decompilers, SWF obfuscators have been introduced to provide a modicum of security, some produced by decompiler authors themselves. The higher-quality obfuscators use traps for the decompilers, making some fail, but none have definitively been shown to protect all content.

Flash Player on various platforms
The Adobe Flash Player is mainly optimized for the Windows 32 bit platform. There is a 32 bit version for Mac OS X; under Linux, version 7 and version 9 are both available. On other platforms, such as Solaris, there are currently no later releases than version 7. Adobe has been criticized for neglecting to optimize its products on non-Microsoft platforms. This has led to poor web surfing performance on Macintosh and Linux computers, since many websites use Flash animations for menus and advertisements. Flash Player 7 for Linux was very CPU hungry in fullscreen mode, resulting in low Frame rates.

Adobe has rewritten the bitmap drawing routines in Flash Player 8 for Mac, using OpenGL planes via Quartz to draw the surfaces. The new drawing code is reported to be actually faster than its Windows counterpart, where JPEG, TIFF or other bitmap images are composited into the animation.

Flash Player 7 for Linux had poor sound support (the sound could lag about a second behind the picture); this issue is reportedly resolved in Flash Player 9. Flash Player 8 was never released for Linux, Adobe stated that they would skip that version and instead focus on preparing Flash Player 9. This decision led to disappointment in the Linux community, with some people feeling that Adobe had abandoned the Linux market. Flash Player 9 for Linux was released in January 2007, providing platform parity once again. This version only supports the Advanced Linux Sound Architecture. In order to get sound output, users of the Open Sound System must either compile and install the abstraction layer flashsupport provided by Adobe, run the Windows Flash Player in a Windows browser through WINE, or alternatively switch to ALSA, which involves upgrading the kernel and possibly the sound card.

Adobe has yet (as of April 2007) to release a Flash Player for the x86-64 architecture on any operating system. There is to date no Linux Flash Player for non-x86 compatible processors (e.g. x86-64 native, PowerPC, ARM, etc.). Adobe employees have said the Flash implementation is very 32-bit specific and porting to 64-bit systems would require a lot of effort[citation needed]. Adobe is currently working on a 64-bit version[15]. Adobe have not yet released any of their development software for any UNIX-like operating system except Mac OS X.