Chapter 8 Digital Media Computer Concepts 2013 8 Section A: Digital - PDF document

12-11-27 Chapter 8 Digital Media Computer Concepts 2013 8 Section A: Digital Sound Ø Digital Audio Basics Ø Digital Audio File Formats Ø MIDI Music Ø Speech Recognition and Synthesis Chapter 8: Digital Media 2 8 Digital Audio Basics Ø Sampling a sound wave Chapter 8: Digital Media 3 1

12-11-27 8 Digital Audio Basics Ø Sampling rate refers to number of times per second that a sound is measured during the recording process Chapter 8: Digital Media 4 8 Digital Audio Basics Ø A sound card is a device that contains a variety of input and output jacks, plus audio-processing circuitry Ø Integrated audio Ø Digital signal processor Chapter 8: Digital Media 5 8 Digital Audio File Formats Ø The most popular digital audio formats include AAC, MP3, Ogg Vorbis, WAV, and WMA Ø Audio or media player software allows you to play digital audio files Ø You can embed digital audio files into a Web page using the HTML5 <audio> tag Ø Streaming audio plays as its file is downloaded Chapter 8: Digital Media 6 2

12-11-27 8 Digital Audio File Formats Ø You can use audio converter software to change audio files from one format to another Ø Ripping is a slang term that refers to the process of importing tracks from a CD or DVD to your computer’s hard disk Ø The technical term is digital audio extraction Ø Music is stored on CDs in a digital format, CDDA Ø During the ripping process, music in CDDA format is typically converted into a compressed format such as MP3, AAC, or WMA to reduce file size Chapter 8: Digital Media 7 8 Section B: Bitmap Graphics Ø Bitmap Basics Ø Scanners and Cameras Ø Image Resolution Ø Color Depth and Palettes Ø Image Compression Chapter 8: Digital Media 8 8 Bitmap Basics Ø Composed of a grid of dots Ø Color of each dot is stored as a binary number Chapter 8: Digital Media 9 3

12-11-27 8 Bitmap Basics Chapter 8: Digital Media 10 8 Scanners and Cameras Chapter 8: Digital Media 11 8 Scanners and Cameras Chapter 8: Digital Media 12 4

12-11-27 8 Scanners and Cameras Ø Digital cameras use storage medium Ø Solid state memory cards Ø Transfer images using: Ø Card readers Ø Direct cable transfer Ø Infrared port Ø Media transfer Ø Docking station Ø E-mail Chapter 8: Digital Media 13 8 Scanners and Cameras Ø Graphics software is used to modify or edit bitmap graphics Ø Modify individual pixels to: Ø Wipe out red eye Ø Erase rabbit ears Ø Retouch photographs Ø Require a bit of storage space Chapter 8: Digital Media 14 8 Image Resolution Ø When you increase the resolution of a bitmap, pixel interpolation may occur Ø Some images may appear pixilated Chapter 8: Digital Media 15 5

12-11-27 8 Color Depth and Palettes Ø Color depth is the number of colors available for use in an image Ø Monochrome bitmap Ø Increasing color depth increases file size Ø True Color bitmap (24-bit bitmap) Ø 32-bit bitmap Ø Color palettes are used to control color depth Ø Grayscale palette Ø System palette Ø Web palette Chapter 8: Digital Media 16 8 Color Depth and Palettes Chapter 8: Digital Media 17 8 Image Compression Ø Any technique that recodes data in an image file so that it contains fewer bits Ø Lossless compression Ø Lossy compression Ø Run-length encoding Ø File compression utility Chapter 8: Digital Media 18 6

12-11-27 8 Image Compression Chapter 8: Digital Media 19 8 Image Compression Chapter 8: Digital Media 20 7