COM 597. Streaming Media Lecture 1. June 21, 2007. What the heck is today’s drill?. My background Definition of Streaming A little data to get you started A discussion of terms Why compress media Workshop setup. The class website can be found here:
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June 21, 2007
Definition of Streaming
A little data to get you started
A discussion of terms
Why compress media
Review the Syllabus
Data that is transferred in an orderly and logical fashion.
For this class it will be defined as audio and video media that is interpreted in real time by a player application on a computer.
This will also include media that is handled in something called a “progressive download”
Streaming is often confused with media that is downloaded to a hard drive for later use. That is just saving a file.
Cost effective way of communicating
Faster time to market
Create more options for communication
Tracking and profiling
Use infrastructure more efficiently
Some Personal Favorites:
Yes, even my kids
Communications and journalism
Business leaders interested in new opportunities
Variables to consider when considering a compression strategy:
Platform --- how will it play on older processors
Portability and cross-platform compatibility
Licensing for tools
Digital rights management
Labor costs (time and money)
If you think about it, Thomas Edison created a media player that transformed the peaks and valleys in the groove of a wax cylinder into electronic signals that moved a speaker, creating pressure waves we could hear. The principal is essentially the same with today’s players.
The Melon Patch Schottische
A snappy band number from 1895, The Melon Patch Schottische,
played by the 23rd Regiment Band of New York
How are on-demand media devices such as the TiVo/DVR and the iPod, along with Video On Demand and other digital media delivery platforms, continuing to alter the traditional media landscape?
Content producers will need to track the “Heavy” on-demand media consumers closely. The growth in this arena are showing that these new broadcasting platforms are not just a fad.
As media becomes ever more portable and flexible, it will require new advertising approaches. Shorter spots, testing of new approaches
Video on demand is ever expanding and approaching critical mass
More information at:
A Codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word "codec" is a portmanteau of any of the following: 'Compressor-Decompressor', 'Coder-Decoder', or 'Compression/Decompression algorithm'
It is the software and/or hardware that squeezes video and audio down and then expands it back out so it can be viewed on playback.
Make the file as small as possible with the least quality loss. But this is a judgment call, and just like art, somewhat subject to interpretation what is best.
What follows are some common terms we will need to commit to memory:
Thousands of Millions
Millions of millions
Thousands of terabytes
Bits per second
Thousands of bits per second (“kila-bits”)
Millions of bits per second (“mega-bits”)
Thousands of millions of bits per second (“giga-bits”)
Sound is measured in tenths of Bels, better known as decibels.
(frames per second)
Super 8 is 16 fps
Film is 24 fps
European standard definition video is 25 fps
North American standard definition video is 29.976 fps
High definition video can be 23.9, 24, 25, 29.976, 30, 59.9 or 60 fps
(inches per second)
Used for analog audio tape
Magnetic tape speeds are commonly an even fraction of 30 ips:
30 ips: The highest professional speed.
15 ips: The most common professional and studio speed for reel to reel including multitrack.
7 1⁄2 ips: The lowest professional speed, The most common speed for pre-recorded reel to reel tapes.
3 ¾ ips: Used on later single speed domestic machines
1 7/8 ips: The standard speed for compact cassettes
dots per inch
dots per millimeter
Some codecs that we will review have several names for the same thing.
Exhibit A: MPEG-4 part 10 This is usually referred to a H.264, but can also be called AVC (Advance Video Coding)
Exhibit B: Windows Media 9 or WM9 The format started life as WM6.5, then WM7, then WM8 before landing on WM9. Because it is becoming a standard for more than just Microsoft products (HDVD) it is officially known as VC1.
MPEG-1 The first compression codec in this family
MPEG-2 Probably the most popular. This is what a DVD is made of
MPEG-4 part 2 The first of the MPEG 4 standards. Supports an alpha channel
MPEG-4 part 10 A more recent standard, and a significant improvement in compression
More than just keeping files small
It is about optimizing throughput on a network.
from 40,000 feet up (the big picture)
Video is basically a three-dimensional array of color pixels. Two dimensions serve as spatial (horizontal and vertical) directions of the moving pictures, and one dimension represents the time domain.
A frame is a set of all pixels that (approximately) correspond to a single point in time.
Compression in simple terms is reducing the data used to display an image, play an audio file or present video. It is used throughout the industry.
Data can not be put back once it has been removed.
Points are usually described with Cartesian values (X-Y)
With temporal compression only the changes from one frame to the next are encoded as often a large number of the pixels will be the same on a series of frames
Low motion example 276 Kbps
Medium motion example 344 Kbps
Fast motion example 354 Kpms
You (your client or boss) have to decide what is an acceptable level of compression based upon the variables we will be discussing in class.