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- John H. Krantz
- Hanover College
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- Slideshows
- Why
- Presenting Using Redirects
- Video (if interested)
- Background
- Delivering in a Webpage
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- Example 1
- Indicate sequence of events
- Carries sense of change
- From Billy – sense of momentum in photo
- Original Loftus Eye Witness testimony was done this way
- How?
- One easy way – use redirects
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- Avi is ~5 meg uncompressed, a t 161 kb compressed but louse image
quality images are ~35 kb each
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- Here are the work of previous students
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- <html>
- <head>
- <title>Image Sequence</title>
- <META HTTP-EQUIV="refresh" CONTENT="3;
URL=page01.html">
- Number is number of seconds before redirect
- </head>
- <body>
- <p>
- This will change in 3 seconds, about</p>
- <p align = "center">
- <img border="0" src="Bobby0000.jpg"
width="512" height="384"></p>
- </body>
- </html>
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- Edit in Text editor
- Just edit new page for link
- Change image shown
- Use Save as
- Remove meta tag for last image
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- Frame rates of monitors far exceed what is needed for movement update
- NTSC video: 30 updates per second
- Movies: 24 updates per second
- Most web video 10 to 15 frames/sec
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- Most Update rates are 10-15 frames/sec
- 5 fps 10 fps 15 fps
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- Critical threshold of flicker rates is about 60 Hz in the fovea
- But gets higher for larger stimuli
- Recommended flicker rates between 66 Hz and 120 Hz (Bridgeman, 1998)
- Most monitors are adequate in this value
- Notice difference between flicker and frame update rate.
- Wagon wheel effect.
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- Pixels are not on continuously during a frame
- In part this is necessary for clean motion
- Typical CRT phosphors last about 4 msec. (Bridgeman, 1998)
- On LCD and other technologies, persistence is longer
- Makes motion less clean but flicker less noticeable
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- Image size
- Keep it small
- 320 x 240 is not uncommon
- Image color depth
- Video Length
- The shorter the better
- This file is ~ 5.5 meg in QuickTime and it is 17 seconds
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- Frame rate: recall difference between apparent motion and flicker
- 10 to 15 is really fine for most cases
- And best you can expect on web
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- Find format of your video camera
- Can use digital zoom
- original camera images are much larger than movie images so will be
shrunk down
- And digital zoom is before movie image
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- Hold camera still or not?
- Movies are limited in duration
- mine is 30 sec or size of disk for 320x240
- Image quality is reasonably good if presented in original size
- But image quality may be reduced to get on web
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- Open more than one
- Basics
- Opens MOV, mpg, avi, mp3, etc.
- Get Movie Information on Movie Menu (ctrl-j in Windows)
- Tracks: separate slices of information: played at same time as other
tracks
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- Selecting a region to edit
- Use guides at bottom
- Called In and Out Markers
- Selected region is darkened
- Arrow keys to fine tune
- Cut and Paste operation
- Paste is at playback head
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- Copy as before
- Use Edit: Add – adds the video track
- Use Edit: Extract Tracks
- Then Edit: Add
- Can extract sound this way to a movie
- Can add scaled so new track is not length of old movie
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- Use Edit: Delete Tracks
- Remove any unwanted sound from video
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- Adding text to beginning
- Make any graphic
- Resize to movie size so know how it will look
- Select al (ctrl-A)
- Then cut and paste to beginning
- Another paste for each additional frame
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- Overlaying Text
- Use a gif file with a transparent background
- Use a text file
- File: Import
- Any .txt
- Press Option button
- Select keyed text
- Change background to white and foreground to text color
- I like changing it to bold
- Add tracks as before
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- Filtering portions of movie
- Delete regions do not want to filter
- Use the export function
- Click on Options
- Click on Filter
- Pick pattern
- Use cut and paste to reassemble
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- Format:
- You must compress
- Uncompressed files will be very large
- Lead very slow download
- Duration
- For same reason, keep videos short
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- Steaming
- Starts sooner
- Can be large files
- Can stop
- Relatively lower quality and quality depends on connection
- General Protocol RTP/RTSP
- Regular Delivery
- Wait for entire file
- Keep to small files
- Keeps Speed
- Relatively better quality, but quality depends upon monitor and format
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- HTTP Fast Start is a feature of QuickTime
- Allows playing after part of file downloaded
- Fewer stops
- No special software
- Still keep files relatively small
- Some loss of image quality
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- <p align="center">
- <OBJECT
CLASSID="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B"
- WIDTH="480" HEIGHT="376“
- CODEBASE="http://www.apple.com/qtactivex/qtplugin.cab">
- <PARAM NAME="src" VALUE="start.mov">
- <PARAM NAME="controller" VALUE="false">
- <PARAM NAME="target" VALUE="myself">
- <PARAM NAME="href" VALUE=“clip.mov">
- <EMBED WIDTH="480" HEIGHT="376"
CONTROLLER="false" TARGET="myself"
HREF=“clip.mov"
- SRC="start.mov"
BGCOLOR="FFFFFF" BORDER="0"
PLUGINSPAGE="http://www.apple.com/quicktime/download/indext.html">
- </EMBED>
- </OBJECT>
- </p>
- Example: http://ati.fullerton.edu/jkrantz/session3/video/
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