Introduction to Multimedia SMDC Staff Training 6/9/06

Goals Understand how Multimedia is represented within a computer Become familiar with some core multimedia concepts and terms Be able to find Multimedia on the Internet Begin thinking of your own Multimedia project

What is Multimedia?

The Multi PartMulti Combine media elements with: Synchronization Navigation Interactivity Metadata

Multimedia Files –Contains one of more media elements and metadata regarding how to decode and possibly decompress it. –Singe accessible unit on a computer Frameworks –Pull together multiple files for presentation and navigation –Points to other files rather than contains them

Digital Information In a computer all digital information is stored in the same format – binary.binary It’s how you encode and decode the binary that determines what the information is. 1 digit = bit (b), 8 bits = Byte (B) (1 kB = 1024 Bytes)1 kB = 1024 Bytes Many systems to store: 0/1, On/Off, +/-, Up/Down

Black and White Pixels █1███111█11█1██11█1█ █1█1█1██1█1█1██1█1█1 █1█1██1█1█1█1█1██1█1 █1█1█1█1█1█1█1█1█1█1 █1█1111█1█1█111██1█1 █111█1█1█1█11█1██1█1 ██1███1██11█1██11███ ████████████████████ ████████████████████ ████████████████████ ████████████████████ ████████████████████ ████████████████████ ████████████████████

Color Depth 8-bit grayscale: –I byte (8 bits) describe one pixel –Amount of grey from – bit color: –3 bytes describe one pixel –Red, Blue Green make up one pixel, blended like light, not paint (Additive Color)Additive Color – –Red (92,5C), Green (192,C0), Blue (92,5C)

Resolution Dots per Inch (DPI)Dots per Inch Image Resolution (A x B)Image Resolution Same Image Resolution, Different DPI

Resolution Dots per Inch (DPI)Dots per Inch Image Resolution (A x B)Image Resolution Same Image Resolution, Different DPI

Resolution Dots per Inch (DPI)Dots per Inch Image Resolution (A x B)Image Resolution Same DPI, Different Image Resolution

Resolution Dots per Inch (DPI)Dots per Inch Image Resolution (A x B)Image Resolution Same DPI, Different Image Resolution

Examples Flickr – Creative Commons –

Video Video is a series of still images – like a flip book Frames per Second (FPS), Frame Rate 24 FPS – Film 29.9 FPS – Video/TV

1 Frame Per Second

5 Frames Per Second

10 Frames Per Second

15 Frames Per Second

24 Frames Per Second

Examples Internet Archive – Video Podcast – iTunes: tore.woa/wa/viewPodcast?id= tore.woa/wa/viewPodcast?id=

How Do You Get 1’s & 0’s? Many of our senses are analog Sight – light waves Touch – continuous motion Hearing – sound waves Think of a graph of something changing over time

Viewing Sound Waves Audacity – free audio recording utility Launch AudacityAudacity

Some Analog to Digital Terms Amplitude Sampling Rate Sampling Bits

Sampling

Interactive Multimedia UD Microscope: po?oid= po?oid= Pipeline:

Compression This will be another day, but… Most audio-visual data files are huge Compression makes files smallerCompression Lossless compression does so without changing the informationLossless compression Lossy compression throws information away to make files smallerLossy compression

Compression Artifacts Uncompressed tiff 319,808 bytes

Compression Artifacts Compressed tiff 3,213 bytes

Compression Artifacts 100% Quality JPG 5,738 bytes

Compression Artifacts 50% Quality JPG 2,874 bytes

Compression Artifacts 25% Quality JPG 2,333 bytes

Compression Artifacts 1% Quality JPG 1,319 bytes

Video Compression Artifacts

Codec Compressor/Decompressor Coder/Decoder Tells computer what the binary 1’s and 0’s are

Finding (Legal) Free Multimedia UD Library Multimedia Resources Library of Congress Internet Archive Merlot Creative Commons

Key Terms Multimedia Synchronization Metadata Digital Binary Encode Decode Analog Codec Compression Pixel Resolution DPI

References and Attributions Iguana Photo (slides 9-12) ©2005 Aaron Logan, used under Creative Commons Attribution 2.5 license Commons Attribution 2.5 license “Pipeline” by Steven H. Silberg - presented with permission of the artisthttp://pipeline.shsarts.com Satellite dish footage from the Internet Archives Prelinger Collection, used under the Creative Commons Public Domain license Audio test files from Fred Nachbaur,

Free Software Used the produce these Materials XNview – Image editing: Audacity – audio recording/editing: TMPGEnc – MPEG Editor/Converter: