Transcript Product Distribution - University of North Texas

Product
Distribution
Mediums,
Strategies and
Compression
Objectives
 Define
& discuss compression
schemes for video
 Identify common distribution
mediums for video
 Discuss post-production
strategies for product
distribution
MiniDV & Digital 8
Signal Format
 DV
25
 25
million
bits/second
 5:1 ratio of
compression
 Intra-Frame
 4:1:1 Color
Two Approaches to Post
Processing

Hardware assisted
conversions





MPEG – 2
Other formats
Conversion during
capture
Conversion after
capture
More expensive
solution
Two Approaches to Post
Processing

Software conversion
after capture



Less expensive
Can be slower
without hardware
assist
Many software
CODEC’s available
Reducing File Size
Reduce Frame Size
 Reduce Frame Rate
 Reduce Audio Rate
 Apply
Compression
 Reduce time in
minutes

CODEC



Short for
“compress/decompress”
Similar to the word
modem—
modulate/demodulate
CODEC software is
mostly for compression
but may also do some
formatting
Compression

The process of
removing or
restructuring
data to decrease
file size
Compression

Compression
converts frames
and pixels to
mathematical
algorithms that
the computer
can understand
Compression
 Decompression
converts
mathematical
algorithms back
to frames and
pixels for
playback
Compression
 Compression
is the primary
function of the
CODEC
Compression
Two Types:
Lossless
Lossy
Keeps All Bits
Removes Bits
Compression
Concepts
Spatial –
Looks within the frame for
compression information (looks
“within” each frame)
 Temporal –

Looks across multiple frames for
compression information (looks
“between” frames)
Compression
Concepts
Most modern CODEC’s use a combination
of spatial and temporal compression
Frame
between
Frame
within
Frame
Frame
Frame
Compression
Concepts
Keyframe Compression
Key
Frame 1
All Saved
Delta
Frame 1
Difference
from Key
Frame
Delta
Frame 2
Delta
Frame 3
Difference
from Delta 1
Difference
from Delta 2
Compression
Concepts
New keyframe must be created at
regular basis throughout video to
have new reference points for
comparison.
 Keyframe timing can be user
defined in non-linear software

Compression
Concepts

Software
compression time
variables





CODEC
Compression Ratios
CPU horsepower
Length in minutes
Amount of change
(i.e. 30 frames to 15)
Compression
Concepts
Video
1
RLE
Sorenson
Indeo
CODECS
MPEG
Cinepac
Where to Go?
 DV
25
 25
million
bits/second
 5:1 ratio of
compression
 Intra-Frame
 4:1:1 Color
Videotape
CD-ROM
DVD
Streaming Media
Videotape
 Keep
parameters the
same!!
 Export
timeline
Print to Video
 Export to Tape

Video returns
to camera via
firewire
Videotape


Excellent way for
students to take
their work to show
off at home
Consider adding
videotapes to
school supply list
CD-ROM

Size limitation!


Approx 650 megs
Change video
parameters to fit project
on CD
Frame
size
# of frames
etc
Make Movie …
Output file
Format selection
MPEG-2 would show if
System had hardware card
Make Movie …
Make Movie …
Choose
CODEC
Make Movie …
Change Audio
Parameters
Make Movie …
Settings for finished project
DVD



Different formats
on market
Approx. 4.7 gigs
per side
Can be used to
“store” just about
anything digital
DVD

For movie-like DVD
Shoot 16X9 format
in camera
 Convert to MPEG-2
for DVD playback
 Take advantage of
stereo capabilities

NOTE: You will need a hardware-assisted card
Streaming Media
Export directly
to streaming
format if
available
 Prepare file,
then export to
streaming media

Streaming Media

Class lectures –
320X240
 15 frames
 Highest quality
compression as
possible
 Process through
Real Producer

Distribution Strategies
Pick an end medium at the
beginning of the pre-production
process!
 What will equipment allow?
 Who will your audience will be?
 Know limitations and parameters of
end medium.

Distribution Strategies
Understand
variations in
CODEC’s
 Experiment to
find optimum
solutions to
post processing

Distribution Strategies
Process one file
for one medium
 “Sharing” rarely
works
 Re post process
project file if
necessary

One Last Tip
Save all your
clips and final
project files!
 It may save you
time and effort
in the future.

content & curriculum
created by
Dr. Mark Mortensen
University of North Texas
Copyright C. Mark Mortensen 2002