Transcript PowerPoint presentation

Adventures in Information
Adding Video to Your Web Site
February 24, 1999
Eileen Flick
Information Services Division
Today’s Overview
Why ?
What ?
How ?
The goal for today is that you leave here with enough
knowledge to be able to start adding video to your
website.
Why Add Video?
• Only one reason . . .
–MOTION!
Why Motion?
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Visual information / learning
Sense of “being there”
Create a mood
Excite the viewer!
Hold interest
Types of Use
• Video Programs
• Distance Learning
• Archives
Examples Page
What is the Technology?
• Digitizing
• Compressing
• Streaming
Digitizing
• “Regular” video is an analog signal
• Computers use digital data
• Use a ‘digitizing’ or ‘capture’ card to
convert the signal into data
• Just like digitizing audio
• Except it’s video :)
Compression
– Uncompressed video is approximately:
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640 x 480 resolution
24 bit color
7,372,800 bits per frame
30 frames per second
Compression
• Occurs while digitizing and when
preparing clips for streaming
• Reducing the quality reduces the amount of
information that must be compressed
– 320x240, 24 bit, 15fps = 26.37 Mbps
• Want to recompress as few as times as
possible
• Most used compressed sizes:
– 320x240 and 160x120
Codecs (Types of Compression)
• Intel Indeo
– PC platform, not compatible w/Quicktime
– doesn’t maintain video quality well
• MPEG
– best compression
– only use if end result will be an MPEG file
• Sorenson
– good compression & quality
– requires Quicktime 3
• Animation
– okay if source is computer-generated, not good with
videotape source
Video File Formats
• Quicktime 3 - Mac standard
– Cross-platform, good compression (Sorenson)
– Must flatten movie for the Web (default Quicktime has
two forks, data & resource)
– movies can stream
• AVI - PC (Windows) standard
– Audio & video interleaved for better quality
– Macs need special apps to play or convert to QT
• MPEG - UNIX standard
– very high compression, good quality
– special encoding tools needed for max use
– more info: http://www.mpeg.org/
Streaming
• Data is played back as it arrives
• Non streamed clips must download
completely before playing back
• The Analogy …
– Streaming is like watching television
– Non-Streaming is like renting a movie
Streaming is Good
• Faster time to initial start of playback
• Almost no storage space is needed on client
computer
• Random access to stream
• Capability to send live streams
Streaming is bad
• Generally lower quality
• Can be more susceptible to the quality of
the network connection
• Requires more time to encode to get the
best quality
• Requires a special server to get all the
benefits of streaming video
True Streaming
Request for meta file
Web Server
Web Browser
pnm meta file
pnm
meta
file
Request for stream
RealPlayer
RealServer
Stream
Pseudo-Streaming
Request for meta file
Web Browser
http meta file
Web Server
Request for media file
http
meta
file
RealPlayer
media file
How Does One Do All This?
• Step 1 - Capture/Digitize the Video
• Step 2 - Encode/Compress it
• Step 3 - Publish it on the web
Step 1a - Capture the Video
- The Hardware On a PC:
• First - Video capture card
• Recommend Osprey 100 or 1000
• Miro DC30 is a poor choice for most users
• Video cards recommended by Real Networks:
http://www.real.com/devzone/library/stream/vidcard.html
• Second - Enough disk space
• Recommend 4+ GB drive
• Third - The Computer
• As fast as possible
• 200+ MHz Processor
Capturing the Video - cont’d
On a Mac:
• AV-capable Mac (7600+ or an AV model)
• 4GB+ hard drive
• Fast processor (pre-Power PC okay, but verrrry
slow)
• Lots of RAM (at least 64MB, more better)
• Note on Firewire:
– New technology for using peripheral devices, including
digitizing video, new G3s use this method
– For more info: http://www.apple.com/firewire/
Step 1b - Capture the Video
- The Software • Only basic functionality is needed
• Most bundled software is fine
• On the Mac, that means Apple Video Player:
Capturing Video - software cont’d
• Use Adobe Premiere if more capabilities are
needed (editing, filters, etc)
– Available in user rooms for PCs and Macs
• Other software possibilities: Avid Cinema, Strata
VideoShop
• For real media, can also encode directly (live, as in
webcasts)
• More on capturing video:
– Real Media:
http://www.real.com/devzone/library/stream/videohints.html
– Quicktime 3:
http://www.apple.com/quicktime/authors/auth-docs.html
Step 2 - Encode the video
• Must make the Stream vs. Non-Stream
decision
• Non-Stream
– QuickTime vs. AVI
– QuickTime is more universal
– Use Premiere if it’s necessary to re-encode the
clip
Step 2 - Encode the Video
• Streaming Video
– RealMedia is recommended solution
– Use RealEncoder to encode
http://www.real.com/products/tools/producer/
– One or multiple versions?
• Who is your audience?
– Use Premiere to prepare clips as necessary
• Add titles, soundtrack, filters
Step 3 - Publish to the Web
• Non-Streaming
– Almost identical to publishing any other
document
• Upload to server then link it in HTML
– QuickTime 3 now cross-platform, can be
streaming or non-streaming
http://www.apple.com/quicktime
Step 3 - Publish to the Web
Linking the Clip
• Simple link
– File downloads, then plays
– <A HREF=“movie.mov”>link the clip</A>
– Let people know format and size: (1.3MB, QT)
• Embedded link
– <EMBED SRC=“movie.mov” autoplay=false
width=160 height=120></EMBED>
– Controller & window appear in page
– Clip plays while downloading
Step 3 - Publish to the Web
Real Media
• True Streaming
– Requires access to RealServer
– Move files to content directory
• At USC, that means the CWIS server
– Create meta-files using pnm URL’s
– Embed or link to meta-files
Step 3 - Publish to the Web
Linking Real Media
• Reference file in local directory points to a
metafile:
– <A HREF=“movie.ram”>real video clip</A>
• Movie.ram file contain actual clip location:
– pnm://www.usc.edu/dept/real/movie.rm
– .ram file is simple text, contains no HTML tags
CWIS Issues
• RealServer is only available on CWIS
• Open to any CWIS user/dept
• Fill out agreement form
http://www.usc.edu/uscweb/authoring/RealMedia
– Agree to 200 MB limit
– Agree to not hog streams
• HTTP Pseudo-streaming available from any
web server
How to Get Setup
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HTTP Pseudo Stream has no setup!
Create content directory
Turn in agreement form
Link is created to your directory
Start streaming!
Use video on your website ...
… not because it is hard ...
… but because it is easy!
–For more information, and an excellent tutorial,
check out:
–http://builder.com/Graphics/Video/ss02.html