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Adobe Flash
Web Design & Development Guide
Adobe Flash
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Adobe Flash |
|
Adobe Flash CS3 under Mac OS X. |
Developer: |
Adobe Systems |
Latest release: |
CS3 (9.0) /
April 16, 2007 |
OS: |
Windows (no native Windows XP Professional x64 Edition support), Mac
OS X, 32-bit Intel compatible GNU/Linux and Solaris (Intel, SPARC)[1] |
Genre: |
Multimedia Content Creator |
License: |
Proprietary EULA |
Website: |
Adobe.com's Flash page |
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.
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.[1] 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, an artist Adam Grofcsik, and a 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 (2000) 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 2000 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.
- On March 15, 2002, Macromedia announced the availability of Macromedia Flash MX and
Macromedia Flash Player 6, with support for video, application
components, shared libraries, and accessibility.
- 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).
- 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.
- 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).[2]
- 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.[3]
- Adobe Flash CS3 in 2007, originated from Flash 8 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)
Adobe Flash CS3 Professional
- FutureSplash Animator (Spring
10 April 1996) - initial
version of Flash with basic editing tools and a timeline
- Flash 1 (November 1996) - a Macromedia re-branded version of the
FutureSplash Animator
- Flash 2 (June 1997) - Released with Flash Player 2, new features
included: the object
library
- 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
- Flash 4 (15 June 1999) - Released with Flash Player 4, new
features included: internal variables, an input field, advanced
Actionscript, and
streaming MP3
- 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
- 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
- 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
- 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.
- 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.
- 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.
- 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.
The important new development in Flash 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 in development at Adobe Labs is the
Apollo 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). While features of Apollo are still being fully
defined, the project aims to be made available in public beta form in early
2007, with final release planned for later that year.
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.
[4]
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, 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, 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.
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,[5]
with 45%-56%[6]
(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.
Adobe offers the specifications of the Flash file format (excluding
specifications of related formats such as AMF) 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.
Free software alternatives
There is, as of late 2006, no complete free software replacement which offers
all the functionality of the latest version of Adobe Flash. Gnash, based on
GameSWF, is a Flash player replacement that is under development and has the
support of Free Software Foundation (FSF). Gnash supports Flash 7 and below, but not
files that require version 8 or 9 features. Open Source projects aim to create a
flash development environment.
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.[7]
It has been noted by industry commentators[3]
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,[8]
and Firefox's
built-in support for SVG continues to grow.[9]
Third-party software
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.
Authoring
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.
Today, several open and free libraries and tool sets exist to generate and
manipulate SWF files on many platforms. These include the Ming library, SWFTools,
and the combination of swfmill and MTASC.
Macromedia has 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.
Many shareware developers produced Flash creation tools and sold them for
under $50 USD 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 $100 USD 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 Boom Studio.
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.
In April of 2006, the Macromedia 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 covers all the new features
offered in Flash v8 including new ActionScript commands, expressive filter
controls, and so on. The file format specification document is typically
obtainable by subscribing to Macromedia's membership system and license
restrictions (which include a prohibition against using these specifications to
develop a free
alternative).
Microsoft Silverlight
Formally released at the
National Association of Broadcasters (NAB) 2007 and formerly under the code
name Windows Presentation Foundation/Everywhere or WPF/E, Silverlight appears to
be Microsoft's entry into the digital delivery of interactive content. A benefit
for Microsoft is that they can push the player down to the majority of their
users through the automatic update feature of their current operating systems.[10]
Criticisms
Simple animation in Flash 6.0; a square moving across the screen in
a motion tween, one of the basic functions of Flash.
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.
Usage
Due to the increase in the use of Flash in aggressive—and even
intrusive—online advertising, tools have emerged that restrict Flash content in
some or all websites by temporarily or permanently turning Flash Player off
depending on user requirements. Examples of such tools are Flashblock and
Adblock for the Mozilla Firefox browser, Internet Explorer browser, Safari browser, all of which are commonly used in conjunction with each
other to allow users to control what Flash content they see.
Many websites rely on Flash being available by default on a user's web
browser and will not check to see if it is available. If Flash is not installed,
users may be unable to access some Flash-dependent websites or site features.
These sites sometimes depend on a fast internet connection, especially a highly
complex website or one with music. While it is possible to see Flash-based sites
with a slower form of internet, such as dial-up, or a slow form of DSL, it may be frustrating for the user. Blocking tools generally do alert the end user
to the fact that Flash content is present on the site, allowing the user to view
it if they wish.
Flash stores its content in a binary file that is not easily accessible by
search engine crawlers. However, this problem can be alleviated with coding
techniques to detect if a client is capable of viewing the flash content and
showing standard markup code if it is not.
Like most new technologies that are easy to learn, Flash Developers will have
trouble developing content that is innovative, yet intuitive enough for novice
users. Over the years, more Flash Developers have learned to appreciate customer
focus while creating content that takes advantage of the latest features.
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
Flash Players from version 989 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 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.
Application flaws
Specially crafted files have been shown to cause Flash applications to
malfunction, by allowing the
execution of malevolent code. The Flash Player has a long history of
security flaws that expose computers to remote attacks. However, exploitation of
these flaws has remained at the proof-of-concept stage and has not escalated
into a real-world problem.
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.
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. However, the same argument cannot be made about those
with ADHD, since the advertisers are actively interfering with an already
accessible website.
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.[11]
While later versions (Flash Player 6 and onwards) support accessibility
functions, site designers may not necessarily design the Flash content with
these considerations in mind.
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 and Linux. 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.[12][13] 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 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 involves upgrading the kernel and typically the sound
card. 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).
Adobe has yet (as of April 2007) to release a Flash Player for the x86-64
architecture on any operating system[14]. 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[15].
Adobe have not yet released any of their development software for any
UNIX-like
operating system except Mac OS X.
Although the myth is that Flash content cannot be indexed properly by search
engine "bots" the problem has been corrected, or at least alleviated, with Flash
CS3. Users can publish Flash CS3 with meta tags that index individual Flash
movie content, such as links, which can be used by search engine bots to
properly categorize the information. In addition, with the implementation of XML
and other external scripting languages (like PHP) flash can now run websites at
greater speeds than their graphic-heavy counterparts (some applications can run
on as few as 50K; about the size of one image).
Digital Rights Management
According to a recent article from BBC News, the latest iteration of Flash
allows copyright holders to embed ads within videos, as well as control how
those videos are used.
[4] 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 March 2007, Adobe claims
Flash reaches 98.7% of desktop Internet users.[5]
Independent market share data is not available because the several companies who
periodically gather browser usage data 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. |
.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. |
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 7. As a video format, Flash is
liked for its ability to be displayed inside browser windows, not for its in
this sense 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
(also available as standalone player) and offers very good platform
compatibility compared to other browser plugins. It is available for many
popular platforms, including Windows, Mac OS X and, to some extent, Linux. Flash
is used as the basis for many popular video sites, including YouTube and Google
Video.
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.[16]
See also
References
External links
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This guide is licensed under the GNU
Free Documentation License. It uses material from the Wikipedia.
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