Audio and Video

Audio

 

Basic Audio file formats

mp3 (.mp3)
  • High quality for the datarate
  • Probably the most popular audio file format
Wave (.wav) Cross-platform originally developed as the standard audio format for Windows
AIFF (.aif, .aiff) Cross-platform originally developed for Mac. Audio Interchage file format.
u-Law (.au) unix standard audio format
midi (.mid)
  • Musical Instrument Digital Interface.
  • No actual audio information.
  • Mathematical commands that describe a series of notes.
  • Small file size.
  • Quality depends on users sound card.

 

Things that effect audio file size

  1. Length of the clip
  2. Number of channels
    1. stereo or mono
  3. Sampling rate
    1. How often an audio file is sampled(measured)
    2. 44.1khz(44,100 times per second is typical and is CD Quality)
  4. Bit depth
    1. the amount of data used to store each sample
    2. usually 16bit
  5. Compression

Streaming Media

2 Protocols for streaming

  1. http: hyper text transfer protocol
  2. rtsp: real time streaming protocol

2 kinds of streaming

  1. true streaming: could be a live event
  2. fake streaming, or progressive download: media that has already been prepared but begins to play as soon as the user gets enough of the file.

Popular Audio/Video Streaming Formats

Realmedia http://www.real.com/
Windows Media http://www.microsoft.com/windows/windowsmedia/default.mspx
Quicktime http://www.apple.com/quicktime/
Flash(Youtube) http://www.youtube.com

Links for streaming media

Other Quicktime embed attributes

Other Realmedia embed atributes and instruction

Quick Steps for Streaming Clips with Realmedia

A good article on streaming Audio:
Web: Making Waves with Streaming Audio
With the Right Tools, It's Cheap and Easy to Add Sound to Your Web Site
By Jim Heid

A Good article on Streaming Video on the Internet

Embedding media into pages

Some tags for embedding media:
MS Movie Clip <IMG DYNSRC="***" START="***" LOOP=?>
MS Background Sound <BGSOUND SRC="***" LOOP=?|INFINITE>

N2 Embed Object <EMBED SRC="URL"> (insert object into page)
N2 Object Size <EMBED SRC="URL" WIDTH=? HEIGHT=?>

 

The embed tag:
<EMBED>
This tag allows different kinds of documents of varying data types to be embedded into an HTML document. It has three default attributes: SRC, WIDTH, and HEIGHT. It may also contain optional parameters that can be sent to the plug-in handling the embedded data type.

SRC=<URL>
The URL of the source document.

WIDTH=<size in pixels>
The WIDTH attribute specifies the width of the embedded document, in pixels.

HEIGHT=<size in pixels>
The HEIGHT attribute specifies the height of the embedded document, in pixels.

PARAMETER_NAME=<PARAMETER_VALUE>
Optional parameters to send to plug-ins. There can be an infinite number of parameters passed to a plug-in. Examples of parameters are PLAY_LOOP=TRUE, or CONTROLS=FALSE. Parameters are specific to each plug-in.

Examples:
<EMBED SRC="MyMovie.mov", WIDTH=150, HEIGHT=250 CONTROLS=TRUE>
<EMBED SRC="DoomGame.ids", WIDTH=400, HEIGHT=300 SPEED=SLOW LEVEL=12>