Digital Media

Question 1

JPEG Aconym and Artifacts

Answer 1

• Joint Photographic Expert Group
• block artifacts
  
  • JPEG divides the image into 8x8 blocks and if the compression is very high, you can see the block boundaries
• edge artifacts/noise
  
  • in a more-compressed version, little “noise” speckles or distortions can appear to either side of the hard edge

Question 2

Image Byte Size

Answer 2

• each pixel takes three bytes (one for each color channel)
• 400 x 300 image = 120,000 pixels x 3 bytes/pixel = 360,000 bytes = 360 KB
• 12 megapixel camera = 4000 x 3000 image

Question 3

GIF and PNG Acronymn

Answer 3

• Graphics Interchange Format
• Portable Network Graphics
• lossless image formats
• PNG performs a little better than GIF

Question 4

Audio Formats

Answer 4

• MP3 = 1 MB/minute
• AAC = modern form of MP3 with Apple
• Ogg Vorbis = free and open alternative to MP3

Question 5

Video Formats

Answer 5

• MPEG = Motion Picture Experts Group
• MPEG-4/H.264
• WebM = Google’s format
• Flash = proprietary format produced by Adobe
  
  • HTML5 will replace Flash

Question 6

What is true about the lossy image format JPEG?

Answer 6

it omits some visual detail so as to take up fewer bytes