• Images include such diverse things as scanned photographs, icons, illustrations, drawings, and simple animation.

• GIF
  • Created by CompuServe.
  • Stands for Graphics Interchange Format.
  • Support 8-bit color and is the most common format.
• JPEG
  • Stands for Joint Photographers Experts Group
  • Can support either 8-bit or 24-bit color.
  • Lossy compression - each time the image is compressed into JPEG format, some of the pixels are discarded.
• PNG
  • Stands for Portable Network Graphics.
  • Supports both 8-bit and 24-bit color.
  • It uses lossless compression algorithm.
  • PNG is currently an open standard, which means that anyone is free to use it and no single body or organization has fixed all the parameters of the standard.
• PDF
  • Stands for Portable Data Format.
  • These images are created with a special software package from Adobe called Acrobat.
  • Any current browser without additional software package that called Acrobat Reader cannot read PDF images.
• TIFF
  • Stands for Tagged Image File Format
  • Commonly used to exchange documents between different computer platforms.
• BMP
  • Is a standard Microsoft Windows image format.
  • It can support 1, 4, 8, and 24 bits per pixel.
• PCX
  • Is an older image format that was developed by Zsoft for the PC Paintbrush program.

   

Image Sizes

• If the image size is large, than the download time will increase.
• 8-bit image is better than the 24-bit image.

Graphics Tips

• Simplify your graphics: Keep the image simple.
• Use the fewest color and save in GIF or JPEG format.
• Avoid dithering (blending two colors among adjacent pixels to achieve a third color).
• Divide up large pages:
• Keep pages under a 50-kilobyte maximum size, including all the graphics.
• Keep large graphics on their own page.
• Reuse the images on your page.

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MULTIMEDIA

Types of Sound Files:

• µ-law (mu-law):
  • most widely support.
  • develop for UNIX operating system.
  • Use a 2:1 compression ratio.
  • Supports only monaural (single channel)
  • File extension - *.au
• RIFF Wave:
  • Resource Interchange File Format Waveform Audio format or Wave
  • Most commonly used on Microsoft Windows products.
  • Can support monaural (single channel) and stereo (multichannel).
  • File extension - *.wav
• AIFF and AIFC:
  • Audio Interchange File Format (AIFF).
  • Use to store high-end audio data.
  • Develop by Apple.
  • AIFF Compressed Format (AIFC)
  • This compression algorithm can compress sounds up to 6:1, but it is a lossy form of compression.
• MPEG Audio:
  • Moving Picture Experts Group (MPEG).
  • This format has the best compression algorithms, which they can compress to ratio of 4:1 with almost no loss of signal quality.
  • MPEG files are usually designated with an extension of *.mp2
• RealAudio (.rm)
  • RealAudio is the predominant streaming technology currently in use on the web.
  • It requires a proprietary player, but basic versions of the player are available free.
• MIDI
  • Musical Instrument Digital Interface format is not a digitized audio format.
  • It represents notes and other information so that music can be synthesized.
  • MIDI is well supported and files are very small, but it is useful for only certain applications due to its sound quality when reproduced on PC hardware.
• RMF
• Rich Music Format as supported by Beatnik is a compact high-quality primarily download-and-play audio format growing in popularity.

Types of Video Files:

• MPEG Video:
  • Most common format for digital video files.
  • MPEG files usually have the file extensions of *.mpg on Intel platforms and *.mpeg on systems that support longer file names.
• QuickTime:
  • Developed by Apple Macintosh.
  • Usually QuickTime movies have an extension of *.qt or *.mov on all platforms.
• Video for Windows:
  • Developed for the PC by Microsoft.
  • Usually have a file extension of *.avi, which stands for Audio/Video Interleave.
• Streaming Audio/Video:
  • One of the newer forms of multimedia is the Shocked movie created with Macromedia's Director program.
  • These multimedia movie presentation s feature streaming audio and video, which means that the movie or audio clip starts as soon as the browser plug-in begins to receive the file.
• ASF
  • Microsoft's Advanced Streaming Format is delivered using their NetShow, now called Windows Media server technology.
  • A rising competitor to RealVideo, ASF files are high quality and commonly supported by Internet Explorer browsers.
• RM
  • RealVideo is the current leader in streaming video technology.
  • RealVideo files can be saved at a variety of quality levels, depending on end-user bandwidth availability.

Animation & Interactivity

• Macromedia Flash
  • Macromedia Flash is an application that developers use to produce interactive, animated movies.
  • Flash can be used to create web-based banner advertisemnts, interactive web sites and web-based applications with stunning graphics and multimedia effects.
  • An advantage Falsh has over other multimedia development applications is that Flash has provides for drawing graphics, generating animation and adding sound and video.
  • Flash movies can be embedded in web pages, placed on CD-ROMs as independent applications or converted into standalone, executable programs.
  • Another advantage of using Flash to produce interactive content is that Falsh includes tols for writing its scripting language, ActionScript.
  • ActionScript is the enabling technology for Flash interactivity. - Macromedia Flash File Formats " .fla file extension is a Flash specific extension for editable movies.
  • Movies can be viewed in their published state with the Falsh Player. Published Flash movies have the file extension .swf, which stands for Shockwave file.
  • Shockwave files are read-only, meaning that they can be viewed but not edited.

Others Animation File Formats

• Animated GIFs
  • Animated GIFs are the simplest form of animation and are supported natively by most browsers.
  • Looping and minimal timing information can be set in an animated GIF, but complex animation is beyond this format's capabilities.
• DHTML
  • DHTML (JavaScript) can be used to move objects around the screen.
  • However, DHTML-based animation tends to be choppy and is not suggested for anything beyond simple button rollover effects. And scrolling text effects.
  • Dreamweaver can add DHTML-based path animations easily to pages.
• Shockwave
  • Shockwave files are compressed Macromedia director files.
  • Their main benefit over Flash is simply that they support complex scripting.
  • However, they can be significantly larger than Flash files.
• Java
  • Java can be used for animation, but it is not suggested.
  • The only major benefit of Java-based animations is that they can be created on the fly based on a complex calculation.
  • The only major use for Java in this sense might be animations created client-side based on user inputs.
  • Java might be used for a simulation or animated graphing application.
  • Java is relatively complex, and is overkill for simple animations.

Web Structure | Web Development