Flash

[ Overview ] [ Why Flash? ] [ Vector vs Bitmapped ] [ Sound and Music ]

Overview

• first introduced as a vector-based program in 1997 when Macromedia purchased the rights to a program called FutureSlash Animator
• now used to create interactive web sites and multimedia at reduced file size
• used by web designers, programmers, educators and students
• graphics and text are created using the drawing tools and animated along the timeline
• bitmapped images, video and audio can be imported
• Actionscript is used to add interactivity to and control movie flow
• editing is done in the main workspace and the results can be tested using Flash Player
• the final product is published as SWF (Flash's native format - Shockwave Flash) or exported as a Quicktime file, a sequential file format , a self-playing movie.
• Flash has its own plug-in that interprets the code of SWF files

Why Flash?

• can be used to create web pages
• can be used to create games that can be played over the Internet
• brings together active elements but is not as complicated or time-consuming as Java and other related programming environments
• is moviemaking software
• is streaming technology which by definition means that while part of the movie is playing on the web the rest is downloading in the background (no need to wait for the entire movie to download prior to viewing)
• generates low-bandwidth files which serves as a benefit for individuals using slower connections because of reduced time to see the movie because of background downloading.
• produces movies that are of high quality
• vector based images saved as Flash files and embedded in the Flash Player file (SWF) and imported into an HTML page are crisp and scalable
• has the ability to antialias image - mathematically blending surrounding pixels to create the illusion of a smoother edge
• can work with bitmapped images
• Flash player files printed from a browser also appear crisp and clear.
• offers greater cross-browser consistency
• the viewer has some control over how the Flash file appears on the web, can zoom in and out of the image and has the ability to change the resolution of an image from high to medium to low.
• is an inbetweening tool that draws all the necessary frames between the key frames
• tweens motion and changes in shape (morphing)
• layered animation
  • can have as many layers as the designer wants
  • used to show depth
  • can focus on one element at a time and still see everything else

   

Vector-Based and Bitmapped Graphics

• Vector-based
  • graphics created with drawing tools
  • no real world images
  • are drawn using mathematical formula
  • resizing a graphic means the image is redrawn by changing one or more of the parameters of the original formula
  • images maintain scale even when enlarged many times - no distortion (a big vector is going to look the same as a small vector)
  • smaller file size
  • plug-ins required to view images
  • suited to creating animation
  • images created in programs such as Macromedia Freehand, Adobe Illustrator, Corel Draw and Flash
• Bitmapped (raster art)
  • best suited for the display of real world images
  • images are comprised of pixels (tiny dots of color) that are assembled to create an image
  • not easy to edit
  • images are resolution dependent and when the size of the image (scaling) is changed pixels are added to or subtracted from the original with the result being distortion (enlarged images may appear "blocky" while smaller images tend to blur)
  • web images are usually bitmap and the two main formats are GIF and JPEG
  • not great for animation
  • larger file size
  • images created in programs such as Adobe Photoshop, Corel's Photo-Paint or Macromedia's Fireworks

Sound and Music

• sound files are considered large and require alot of memory
• digital sound is considered to be sampled sound - recorded by taking samples of a sound every fraction of a second and storing it in bits and bytes.
• sounds cannot be created in Flash - all sounds must be imported

Sample Rate and Sample Size

• sample rate indicates the number of times the samples are stored and is measured in hertz (Hz) or kilohertz (kHz) - a higher sample rate results in better sound resoultion
  • 44.1 kHz - CD quality and best quality
  • 22.05 kHz - recommended sound setting for use on the web
  • 11.025 kHz - AM quality or voice quality
• sample size is information stored on the sound and is referred to as bit resolution - the higher the bit rate the clearer the sound
  • an 8-bit sample size uses 256 units of data to describe a current sound level
  • a 16-bit sample size uses approximately 65,000 data units to describe the same current sound
• an optimal setting of 22kHz with 8-bit mono sound is recommended (mono sound cuts the file size in half). For example:
  • using a 60 second sound and 16-bit stereo the sample size
    • at 44.1 kHz would be 10.5 MB in size
    • at 22.1 kHz would be 5.25 MB in size
  • using a 60 second sound and 16-bit mono the sample size
    • at 44.1 kHz would be approximately 5.25 MB in size
    • at 22.1 kHz would be approximately 2.625 MB in size
  • using a 60 second sound and 8-bit mono the sample size at 22.1 kHz would 1.3 MB in size
• if sound is sampled as a loop the sound file size can be keep down without sacrificing too much sound. By definition looping refers to the extraction of a small amount of sound and visually matching the beginning and end of the sound wave which results in a continuous sound when played.

Sound File Types

• the following sound file formats can be imported:
  • the most popular
    • WAV (.wav) - pronounced "wave" and created by Microsoft and IBM is the standard sound format for Windows and can be read by Macs with Quicktime 4.
    • AIFF (.aif) - Audio Interchange File Format created by Apple Computer is the standard Mac sound format. and can be read by Windows machines with Quicktime 4.
    • MP3 (.mp3) - the most effective and efficient sound file compression (reduces file size while retaining good sound quality) and is both Macs and Windows compatible.
  • the following can be imported if Quicktime 4 or higher is installed on the computer
    • Sun AU - Mac
    • Sound Only Quicktime Movies - Mac and Windows systems
    • System 7 Sounds - Mac
    • Sound Designer II - Mac