Adobe Flash

Adobe Flash

File:AdobeFlashCS3OSX.png Adobe Flash CS3 under Mac OS X.
Developer(s)	Adobe Systems
Stable release	CS3 (9.0.2) / December 12 2007
Operating system	Windows (no native Windows XP Professional x64 Edition support), Mac OS X Player support only: GNU/Linux (Intel, x86) and Solaris (Intel, SPARC)[1]
Type	Multimedia Content Creator
License	Proprietary EULA
Website	Adobe.com's Flash page

Adobe Flash, also known as Shockwave 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.

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.

History

Flash grew out of a chain of thought that started in the 1980s with some ideas Jonathan Gay had at school, then at college and later while working for Silicon Beach Software and its successors. In January 1993, Charlie Jackson, Jonathan Gay, and Michelle Welsh started a small software company called FutureWave Software and created their first product, SmartSketch. A drawing application, SmartSketch was designed to make creating computer graphics as simple as drawing on paper. Although SmartSketch was an innovative drawing application, it didn't gain enough of a foothold in its market. As the Internet began to thrive, FutureWave began to realize the potential for a vector-based web animation tool that might easily challenge Macromedia's often slow-to-download Shockwave technology. In 1995, FutureWave modified SmartSketch by adding frame-by-frame animation features and re-released it as FutureSplash Animator on Macintosh and PC. By that time, the company had added a second programmer Robert Tatsumi, artist Adam Grofcsik, and PR specialist Ralph Mittman. The product was offered to Adobe and used by Microsoft in its early (MSN) work with the Internet. In December 1996, Macromedia acquired the vector-based animation software and later released it as Flash 1.0.

• Macromedia Flash 2 (1997) Features: Support of stereo sound, enhanced bitmap integration, buttons, the Library, and the capability to tween color changes.
• Macromedia Flash 3 (1998) Features: Brought improvements to animation, playback, and publishing, as well as the introduction of simple script commands for interactivity. Macromedia ships its 100,000th Flash product this year, as well.
• Macromedia Flash 4 (1999) Features: Achieved 100 million installations of the Flash Player, thanks in part to its inclusion with Microsoft Internet Explorer 5. Flash 4 saw the introduction of streaming MP3s and the Motion Tween. Initially, the Flash Player plug-in was not bundled with popular web browsers and users had to visit Macromedia website to download it, but as of year 2000, the Flash Player was already being distributed with all AOL, Netscape and Internet Explorer browsers. Two years later it shipped with all releases of Windows XP. The install-base of the Flash Player reached 92% of all Internet users.
• Macromedia Flash 5 (2001) Features: Flash 5 was a major leap forward in capability, with the evolution of Flash's scripting capabilities as released as ActionScript. Flash 5 also saw the ability to customize the authoring environment's interface.
• Macromedia Generator was the first initiative from Macromedia to separate design from content in Flash files. Generator 2.0 was released in April 2001 and featured real-time server-side generation of Flash content in its Enterprise Edition. Generator was discontinued in 2002 in favor of new technologies such as Flash Remoting, which allows for seamless transmission of data between the server and the client, and ColdFusion Server.
• In October 2000, usability guru Jakob Nielsen wrote a polemic article regarding usability of Flash content entitled "Flash 99% Bad". (Macromedia later hired Nielsen to help them improve Flash usability.)
• In September 2001, a survey made for Macromedia by Media Metrix showed that out of the 10 biggest websites in the United States, 7 were making use of Flash content.
• Macromedia Flash MX was released on March 15 2002, with the new Macromedia Flash Player 6 with support for video, application components, shared libraries, and accessibility.
• Macromedia Flash Communication Server MX, also released in 2002, allowed video to be streamed to Flash Player 6 (otherwise the video could be embedded into the Flash movie).
• Macromedia Flash MX 2004 was released in September 2003, with features such as faster runtime performance up to 8 times with the enhanced compiler and the new Macromedia Flash Player 7, ability to create charts, graphs and additional text effects with the new support for extensions (sold separately), high fidelity import of PDF and Adobe Illustrator 10 files, mobile and device development and a forms-based development environment. ActionScript 2.0 was also introduced, giving developers a formal Object-Oriented approach to ActionScript. V2 Components replaced Flash MX's components, being rewritten from the ground up to take advantage of ActionScript 2.0 and Object-Oriented principles. Flash MX 2004 was the first release of Flash to be segmented into "Basic" and "Professional" versions. The Basic version was targeted at traditional Flash animators while the Professional version brought more advanced capabilities that developers would use, for example the data components.
• In 2004, the "Flash Platform" was introduced. This expanded Flash to more than the Flash authoring tool. Flex 1.0 and Breeze 1.0 were released, both of which utilized the Flash Player as a delivery method but relied on tools other than the Flash authoring program to create Flash applications and presentations. Flash Lite 1.1 was also released, enabling mobile phones to play Flash content.
• Macromedia Flash 8 (2005) is touted by Macromedia as the most significant upgrade to Flash since Flash 5. New features included filter effects and blending modes, bitmap caching, a new video codec called On2 VP6, an enhanced type rendering engine called FlashType, an emulator for mobile devices, and several enhancements to the ActionScript 2.0 spec, such as the BitmapData class, several geometric classes, and the ConvolutionFilter and DisplacmentMapFilter classes.
• Macromedia Flash Lite 2 was also released in 2005, which brought its capabilities in line with Flash Player 7.
• On December 3 2005, Adobe Systems acquired Macromedia and its product portfolio (including Flash).
• Adobe Flash Player 9 was released for Windows and Mac OS in 2006, which marked the first time a Flash Player major release occurred without a simultaneous Flash authoring program major release. Flex 2.0 was released in conjunction with Flash Player 9, and the player will be continued when Flash Authoring 9 is released in 2007. For the first time in the history of Flash, the Flash Player will have had an opportunity to become widely installed before the release of the equivalent Flash program.
• Adobe Flash Player 9 was released for Linux in January 2007.
• Adobe Flash 9 Public Alpha was released in 2006, and was a preview of ActionScript 3.0.
• Adobe Flash CS3 in 2007, originated from Flash 9 Public Alpha with several updates for integrating into other Adobe products, is released as a bundled software of the Adobe Creative Suite 3. This currently-newest version also brings ActionScript 3.0 and a new xml engine to the Flash authoring tool. Also has an improved and optimized GUI like the rest of the CS3 suite.

History (authoring tool)

• FutureSplash Animator (Spring 10 April 1996) – initial version of Flash with basic editing tools and a timeline
• Macromedia Flash 1 (November 1996) – a Macromedia re-branded version of the FutureSplash Animator
• Macromedia Flash 2 (June 1997) – Released with Flash Player 2, new features included: the object library
• Macromedia Flash 3 (31 May 1998) – Released with Flash Player 3, new features included: the movieclip element, JavaScript plug-in integration, transparency and an external stand alone player
• Macromedia Flash 4 (15 June 1999) – Released with Flash Player 4, new features included: internal variables, an input field, advanced Actionscript, and streaming MP3
• Macromedia Flash 5 (24 August 2000) – Released with Flash Player 5, new features included: ActionScript 1.0 (based on ECMAScript, making it very similar to JavaScript in syntax), XML support, Smartclips (the precursor to components in Flash), HTML text formatting added for dynamic text
• Macromedia Flash MX (ver 6) (15 March 2002) – Released with Flash Player 6, new features included: a video codec (Sorenson Spark), Unicode, v1 UI Components, compression, ActionScript vector drawing API
• Macromedia Flash MX 2004 (ver 7) (9 September 2003) – Released with Flash Player 7, new features included: Actionscript 2.0 (which enabled an object-oriented programming model for Flash), behaviors, extensibility layer (JSAPI), alias text support, timeline effects
• Macromedia Flash MX Professional 2004 (ver 7) (9 September 2003) – Released with Flash Player 7, new features included all Flash MX 2004 features plus: Screens (forms for non-linear state-based development and slides for organizing content in a linear slide format like PowerPoint), web services integration, video import wizard, Media Playback components (which encapsulate a complete MP3 and/or FLV player in a component that may be placed in a SWF), Data components (DataSet, XMLConnector, WebServicesConnector, XUpdateResolver, etc) and data binding APIs, the Project Panel, v2 UI components, and Transition class libraries.
• Macromedia Flash Basic 8 (released on 13 September 2005) – A less feature-rich version of the Flash authoring tool targeted at new users who only want to do basic drawing, animation and interactivity. Released with Flash Player 8, this version of the product has limited support for video and advanced graphical and animation effects.
• Macromedia Flash Professional 8 (released on 13 September 2005) – Released with the Flash Player 8, Flash Professional 8 added features focused on expressiveness, quality, video, and mobile authoring. New features included Filters and blend modes, easing control for animation, enhanced stroke properties (caps and joins), object-based drawing mode, run-time bitmap caching, FlashType advanced anti-aliasing for text, On2 VP6 advanced video codec, support for alpha transparency in video, a stand-alone encoder and advanced video importer, cue point support in FLV files, an advanced video playback component, and an interactive mobile device emulator.
• Adobe Flash CS3 Professional (as version 9, released on 16 April 2007) – Flash CS3 is the first version of Flash released under the Adobe name. CS3 features full support for ActionScript 3.0, allows tweens to be converted into ActionScript, adds better integration with other Adobe products such as Adobe Photoshop, and also provides better Vector drawing behavior, becoming more similar to Adobe Illustrator and Adobe Fireworks.

Future developments

Adobe Labs (previously Macromedia Labs) is a source for early looks at emerging products and technologies from Adobe-Macromedia, including downloads of the latest software and plugins. Flash 9, Flex 2, and ActionScript 3.0 are discussed on the labs.adobe.com website.

An important new development in Flash (as of 2007) is its increasing use in providing the presentation layer in handheld devices. Adobe is aggressively courting cell phone and PDA vendors, and partnering to deploy Flash Lite as the user interface.

A project currently (Nov 2007) in development at Adobe Labs is the Adobe AIR Project[2] which is a cross-OS runtime that allows developers to reuse their existing web development skills (Flash, Flex, HTML, Ajax) to build and deploy desktop Rich Internet Applications (RIAs).

The next version of Flash will have two additional components designed for large scale implementation. Adobe is adding in the option to require an ad to be played in full before the main video piece is played. This would be most useful for large scale video sites. Also, Adobe has announced plans to add DRM into the new version of Flash. This way Adobe can give companies the option to link an advertisement with content and make sure that both are played and that they are not changed.

Programming language

Main article: ActionScript

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, an implementation of the ECMAScript standard which therefore has the same syntax as JavaScript, but in a different programming framework with a different associated 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 strived 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 is 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.

This technology can be used in players like those on MySpace and YouTube, to provide protection for the content that the Flash calls, like MP3s and videos. The content called is streamed through the Flash files, and provides a untraceable file for most people, though programs like Firebug can trace the XML files.

Content protection

Often, 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.

Competition

Format and plug-in

Compared to other plug-ins such as Java, Acrobat Reader, QuickTime or Windows Media Player, the Flash Player has a small install size, quick download time, and fast initialization time. However, care must be taken to detect and embed the Flash Player in (X)HTML in a W3C compliant way. A simple and widely used workaround is provided below:

<object data="movie.swf" type="application/x-shockwave-flash" width="500" height="500">
    <param name="movie" value="movie.swf" />
</object>

More Information on how to detect and embed Flash Objects in a W3C compliant way is provided in the xSWF description.

The use of vector graphics combined with program code allows Flash files to be smaller, or streams to use less bandwidth, than the corresponding bitmaps or video clips. For content in a single format (such as just text, video or audio) other alternatives may provide better performance and consume less CPU power than the corresponding Flash movie, for example when using transparency or making large screen updates such as photographic or text fades.

In addition to a vector-rendering engine, the Flash Player includes a virtual machine called the ActionScript Virtual Machine (AVM) for scripting interactivity at run-time, support for video, MP3-based audio, and bitmap graphics. As of Flash Player 8, it offers two video codecs: On2 Technologies VP6 and Sorenson Spark, and run-time support for JPEG, Progressive JPEG, PNG, and GIF. In the next version, Flash is slated to use a just-in-time compiler for the ActionScript engine.

Flash as a format has become very widespread on the desktop market. According to a NPD study, 98% of US Web users have the Flash Player installed, with 45%–56% (depending on region) having the latest version. Numbers vary depending on the detection scheme and research demographics.

Flash players exist for a wide variety of different systems and devices. Flash content can run consistently on Microsoft Windows, Mac OS, and Linux (Macromedia has created or licensed players for the following operating systems: Windows, Mac OS 9/X, Solaris, HP-UX, Pocket PC, OS/2, QNX, Symbian, Palm OS, BeOS, and IRIX). See also Macromedia Flash Lite for Flash compatibility on other devices.

Open standard alternatives

A full end-to-end implementation of the W3C SVG and SMIL specifications would offer close competition for most of the features of Flash in an open, standard way. Adobe used to develop and distribute the 'Adobe SVG Viewer' client plug-in for MS Internet Explorer, but has recently announced its discontinuation. It has been noted by industry commentators that this is probably no coincidence at a time when Adobe has moved from competing with Macromedia's Flash, to owning the technology itself. Meanwhile, Opera has supported SVG since version 8, and Firefox's built-in support for SVG continues to grow.

libavg is a high-performance open source alternative for media-rich applications that aren't browser-based.

Third-party implementation

Specifications

In October 1998, Macromedia disclosed the Flash Version 3 Specification to the world on its website. It did this in response to many new and often semi-open formats competing with SWF, such as Xara's Flare and Sharp's Extended Vector Animation formats. Several developers quickly created a C library for producing SWF. February 1999 saw the launch of MorphInk 99, the first third party program to create SWF files. Macromedia also hired Middlesoft to create a freely available developers' kit for the SWF file format versions 3 to 5.

Macromedia made the Flash Files specifications for versions 6 and later available only under a non-disclosure agreement, but it is widely available from various sites.

In April of 2006, the Flash SWF file format specification was released with details on the then newest version format (Flash 8). Although still lacking specific information on the incorporated video compression formats (On2, Sorenson Spark, etc.), this new documentation covered all the new features offered in Flash v8 including new ActionScript commands, expressive filter controls, and so on. The file format specification document is offered only to developers who agree to a license agreement that permits them to use the specifications only to develop programs that can export to the Flash file format. The license forbids the use of the specifications to create programs that can be used for playback of Flash files. The Flash 9 specification was made available under similar restrictions.

Playback

Since Flash files do not depend on an open standard such as SVG, this reduces the incentive for non-commercial software to support the format, although there are several third party tools which use and generate the SWF file format. IrfanView is capable of playing SWF files. There is a large and vibrant open source community. Flash Player cannot ship as part of a pure open source, or completely free operating system, as its distribution is bound to the Macromedia Licensing Program and subject to approval.

There is, as of late 2007, no complete free software replacement which offers all the functionality of the latest version of Adobe Flash Player. Gnash, based on GameSWF, is a Flash player replacement that is under development and has the support of the Free Software Foundation, see High Priority Free Software Projects. Gnash supports Flash 7 and below, but not files that require version 8 or 9 features. Swfdec is another open-source flash player available for Linux and FreeBSD.

Authoring

Open Source projects like Ajax Animator, and UIRA aim to create a flash development environment, complete with a graphical user environment. Alternatively, programs such as swfmill, SWFTools, and MTASC provide tools to create SWF files, but do so by compiling text, actionscript or XML files into Flash animations. It is also possible to create SWF files programmatically using the Ming library, which has interfaces for C, PHP, C++, Perl, Python, and Ruby.

Many shareware developers produced Flash creation tools and sold them for under US$50 between 2000 and 2002. In 2003 competition and the emergence of free Flash creation tools, most notably OpenOffice.org Impress, had driven many third-party Flash-creation tool-makers out of the market, allowing the remaining developers to raise their prices, although many of the products still cost less than US$100 and support ActionScript. As for open source tools, KToon can edit vectors and generate SWF, but its interface is very different from Macromedia's. Another, more recent example of a Flash creation tool is SWiSH Max made by an ex-employee of Macromedia. Toon Boom Technologies also sells traditional animation tool, based on Flash - Toon-Army. Anime Studio is a 2D animation software specialised for character animation which creates SWF files.

Adobe wrote a software package called Adobe LiveMotion, designed to create interactive animation content and export it to a variety of formats, including SWF. LiveMotion went through two major releases, but failed to gain any notable user base. Cartoon Man X Studios is one of the studios that uses this software.

In February 2003, Macromedia purchased Presedia, which had developed a Flash authoring tool that automatically converted PowerPoint Files into Flash. Macromedia subsequently released the new product as Breeze, which included many new enhancements. Since that time, Macromedia has seen competing PowerPoint-to-Flash authoring tools from PointeCast (not to be confused with PointCast) and PresentationPro among others. In addition, (as of version 2) Apple's Keynote presentation software also allows users to create interactive presentations and export to SWF.

Criticisms

Simple animation in Flash 6.0; a square moving across the screen in a motion tween, one of the basic functions of Flash.

File:Flash alerts.jpg

Typical error message with Flash. A. Your computer may need a newer version of Flash that it can support. B. CPU usage may disable slower computers. C. Security concerns.

Usability

Many usability concerns regarding Flash are due to the fact that Flash breaks with many of the conventions associated with normal HTML pages. Things like selecting text, scrollbars, form control and right-clicking act in a different way than with a regular HTML webpage, and it is argued that this contributes to a usability issue. The usability expert Jakob Nielsen publish an Alertbox in 2000 entitled, Flash: 99% Bad which listed many of these issues. Much of the criticism of Flash in these rergards is due to poor implementation. For example, bookmarking and selecting text are something that many Flash pages do not handle, but is something that is often not implemented due to time, cost or lack of knowledge.

Webpages which make heavy use of Flash can also cause difficulties for some users, such as those using old hardware or who cannot install or use Flash Player. As Flash elements often include a lot of graphics and sound, dial-up internet users are also affected by higher page load times, although there is a more general trend toward larger websites as high-speed internet becomes more common.

Accessibility issues

The US Justice Department has stated in regard to the Americans with Disabilites Act:

"Covered entities under the ADA are required to provide effective communication, regardless of whether they generally communicate through print media, audio media, or computerized media such as the Internet. Covered entities that use the Internet for communications regarding their programs, goods, or services must be prepared to offer those communications through accessible means as well."

Currently, businesses are able to sidestep this mandate to a great degree because the increased cost and complexity associated with providing content to sight-challenged viewers.

Although long since fixed with accessibility functions since Flash Player 6, Internet users who are visually-impaired, and who may rely on a screen reader, braille display, or using larger text sizes and/or high-contrast color schemes may find sites that make extensive use of Flash difficult or impossible to use.

Using Flash to restrict access to content

Many content producers use Flash as a way to limit user's access to the media displayed in their browsers, and/or gain clicks by forcing extra steps to display. For example, in Windows, Shockwave/Flash (.swf) files cannot be right-clicked and saved. Famously, YouTube furnishes all video in flash video format (.flv), requiring users to turn to third-party solutions to store the content locally. The usage is now spreading to photo sharing websites such as Webshots. A Flash overlay exists over the initial photo displayed, requiring a second click to retrieve the photo, slowing the experience considerably. However, if Flash is not installed, the image displays normally.

Local Shared Objects

Main article: Local Shared Object

Flash Players from version 6 can store and retrieve persistent data without offering any visible signs to the user—in a manner similar to that of cookies. It is possible to clear the temporary files that Flash stores on your computer either through the Flash website, or by clearing the files manually. The default storage location for LSOs is operating-system dependent. For Windows XP, the location is within each user's Application Data directory, under Macromedia\Flash Player\#SharedObjects. For Windows Vista it is in each user's AppData directory under Roaming\Macromedia\Flash Player\#SharedObjects. For Mac OS X the location is in each users Library directory under Preferences/Macromedia/Flash Player/#SharedObjects. On Linux the location is in each users directory: ~/.macromedia/Flash_Player/#SharedObjects.

Security issues

Specially crafted files have been shown to cause Flash applications to malfunction, by allowing the execution of malevolent code. Users who have not updated their Flash Player to the most recent version may be vulnerable to such an attack.

In addition to entries in the Open Source Vulnerability Database, security advisories published in August 2002, December 2002, and November 2005 highlight three examples of reports about various Flash Player versions that allowed remote code execution.

Flash Player on various platforms

The Adobe Flash Player is mainly optimized for the Windows 32 bit platform. 32 bit editions of version 9 are also available for Mac OS X, Linux, and Solaris. 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 with Flash prior to version 9, 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.

The Linux version of the Flash Player requires the Advanced Linux Sound Architecture (ALSA) to output sound. ALSA was introduced in Linux 2.5 and can only be used with recent sound hardware. Users of the legacy 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 switch to ALSA, which may involve recompiling or upgrading the kernel and/or installing additional drivers. However, it is questionable how many of the Linux users would be able to identify this problem. On Flash Player 7 for Linux, the sound could lag about a second behind the picture; this issue was 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. On Linux, it is generally not possible to scroll a web page while the mouse cursor is held over a flash animation (On some distributions, it is possible by using the arrow keys after a mouse click on the page outside the flash). Long news sites may be a pain to scroll through, as they often contain flash animations spread out all over, so that one must slalom the cursor around the flash content while scrolling.

Adobe has yet (as of November 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. Adobe is currently working on a 64-bit version. Adobe has not yet released any of their development software for any UNIX-like operating system except Mac OS X.

Search engine indexability

Flash files are binary data, and as a result are not as easily indexable as other document formats. Also, due to their dynamic nature, often it's not possible for a search engine to link to a specific section in an all-Flash site.

Some method have emerged to try deal with this problem. Adobe have a Flash Search Engine SDK, and Flash CS3 creates addition meta information that is indexable by search engines. One approach which has become popular is creating a base HTML page with indexable content, and adding an additional flash layer. This method of 'progressive enhancement' has become more popular in recent years.

Digital rights management

The latest iteration of Flash allows copyright holders to embed ads within videos, as well as control how those videos are used. With this latest piece of software, companies will be able to quickly remove any video that they feel violates copyright and force advertisements to play prior to the start of the video.

Market share

According to a Millward Brown survey, conducted June 2007, Adobe claims Flash reaches 99.3% of desktop Internet users. Independent market share data is not available because the several companies who periodically gather browser usage data (see Usage share of web browsers) do not measure Flash penetration.

Related file formats and extensions

Ext.	Explanation
.swf	.swf files are completed, compiled and published files that cannot be edited with Adobe Flash. However, many '.swf decompilers' do exist. Attempting to import .swf files using Flash allows it to retrieve some assets from the .swf, but not all.
.fla	.fla files contain source material for the Flash application. Flash authoring software can edit FLA files and compile them into .swf files.
.as	.as files contain ActionScript source code in simple source files. FLA files can also contain Actionscript code directly, but separate external .as files often emerge for structural reasons, or to expose the code to versioning applications. They sometimes use the extension .actionscript
.swd	.swd files are temporary debugging files used during Flash development. Once finished developing a Flash project these files are not needed and can be removed.
.asc	.asc files contain Server-Side ActionScript, which is used to develop efficient and flexible client-server Macromedia Flash Communication Server MX applications.
.flv	.flv files are Flash video files, as created by Adobe Flash, ffmpeg, Sorenson Squeeze, or On2 Flix.
.f4v	.f4v files are standard mp4 files that can be played back by Flash Player 9 Update 3 and above.
.f4p	.f4p files are mp4 files protected with digital rights management.
.f4a	.f4a files are mp4 files that contain only audio streams.
.f4b	.f4b files are mp4 audio book files.
.swc	.swc files are used for distributing components; they contain a compiled clip, the component's ActionScript class file, and other files that describe the component.
.jsfl	.jsfl files are used to add functionality in the Flash Authoring environment; they contain Javascript code and access the Flash Javascript API.
.swt	.swt files are 'templatized' forms of .swf files, used by Macromedia Generator
.flp	.flp files are XML files used to reference all the document files contained in a Flash Project. Flash Projects allow the user to group multiple, related files together to assist in Flash project organization, compilation and build.
.spl	.spl files are FutureSplash documents.
.aso	.aso files are cache files used during Flash development, containing compiled ActionScript byte code. An ASO file is recreated when a change in its corresponding class files is detected. Occasionally the Flash IDE does not recognize that a recompile is necessary, and these cache files must be deleted manually. They are located in %USERPROFILE%\Local Settings\Application Data\Macromedia\Flash8\en\Configuration\Classes\aso on Win32 / Flash8.
.lmv	.lmv files is the equivalent to .fla file. These files are also the source material for the open-source program Liveswif, which can also compile them into .swf files.

Video in web pages

Flash is increasingly used as a way to display video clips on web pages, a feature available since Flash Player version 6. As a video format, Flash is liked for its ability to be displayed inside browser windows, and not for its relatively limited platform compatibility. While there are other video file types that can be played on more platforms, typically 'out of the box' on the majority of operating systems, their browser plugins are limited in distribution. In contrast, the Adobe Flash Player is a dedicated browser plugin, but also available as standalone player. It is available for many popular platforms, including Windows, Mac OS X and Linux. Flash is used as the basis for many popular video sites, including YouTube and Google Video. One major flaw with multimedia embedded through Flash, however, is the considerable performance penalty placed on playback hardware as compared with a proper multimedia playback system. Many files that drop frames and skip audio when embedded within Flash play without any issues using normal multimedia formats on the same hardware.

Flash Video (.flv files) is a container format, meaning that it is not a video format in itself, but can contain other formats. The video in Flash is encoded in H.263, and starting with Flash player 8, it may alternatively be encoded in VP6. The audio is in MP3. The use of VP6 is common in many companies, because of the large adoption rates of Flash Player 8 and Flash Player 9.

On August 20, 2007, Adobe announced on its blog that with Update 3 of the Flash Player (currently in beta), Flash Video will also support the MPEG-4 international standard. Specifically, Flash Player will have support for video compressed in H.264 (MPEG-4 Part 10), audio compressed using AAC (MPEG-4 Part 3), the MP4, M4V, M4A, 3GP and MOV multimedia container formats (MPEG-4 Part 14), 3GPP Timed Text specification (MPEG-4 Part 17) which is a standardized subtitle format and partial parsing support for the 'ilst' atom which is the ID3 equivalent iTunes uses to store metadata. Adobe also announced that they will be gradually moving away from the proprietary FLV format to the standard MP4 format owing to functional limits with the FLV structure when streaming H.264. The final release of the Flash Player supporting MPEG-4 is expected to be available in Fall 2007.

See also

• Actionscript
• Flash animation
• Adobe Flash Lite
• Adobe Flex
• Adobe AIR
• Macromedia Shockwave
• OpenLaszlo

External links

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