digital video an introduction to the digital signal file formats acquisition ieee 1394
TRANSCRIPT
DigitalDigitalVideoVideo
AnIntroduction
to the Digital Signal
File Formats
Acquisition
IEEE 1394
ObjectivesObjectives
Identify common file formats Discuss the components of the
digital video signal Discuss acquisition strategies Investigate spec’s for MiniDV and
IEEE 1394
Digital Video Is . . .Digital Video Is . . .
Does not include video devices controlled by a computer such as a level 3 laserdisc.
Any video that plays on a computer as a digital signal.
Hardware SuggestionsHardware Suggestions
High speed Pentium Pentium II with 500MHz will work Bigger and faster is better!
Lots of RAM 128 should work 512 meg or more really improves
performance!
Hardware SuggestionsHardware Suggestions
Hard Drive – Large & Fast Average MiniDV rate is 3.5
megs/second! Firewire card Sound card Fast bus architecture
Software SuggestionsSoftware Suggestions
Modern Operating System! Win 98 has a file size limit Win 2000 or XP better for PC
Non-Linear Editing Software Graphics Software Special Effects Software Authoring Software Other Utilities as needed
Video File FormatsVideo File Formats
AVI Audio Video Interleaved Microsoft's native format
Video File FormatsVideo File Formats
AVI File format, standard, etc. Debuted in 1992 A response to Apple's QuickTime
format Both an application package and a
system architecture
Video File FormatsVideo File Formats
MOV "QuickTime" Apple's native
format
Video File FormatsVideo File Formats
MOV Also available in a Windows
compatible format Multiple versions of QuickTime
floating around!! I'm not sure what the most current
version is (5.0)
.AVI & .MOV.AVI & .MOV
Both formats are standards and relatively stable.
All formats are dependent on what CODECCODEC was used for compression.
Video File FormatsVideo File Formats
MPG Motion Picture Experts Group High expectation -- low result!
Video File FormatsVideo File Formats
MPG Uses hardware compression Compression technique is "lossy“ MPEG-2 is a common DVD format
Video File FormatsVideo File Formats
FLI "FLIC" format used by AutoDesk
Animator DVI
Digital Video Interactive Format comes and goes Some CD use
Prediction . . . .Prediction . . . .
Traditional formats based in the analog world will eventually disappear as new digital domain formats emerge as standard.
Good-bye AVI & MOVGood-bye AVI & MOV
Hello MPG!Hello MPG!
File Size CommonFile Size Common Variables Variables
Display (Picture) Size Video Rate (# of frames) Audio Rate Color Model (Depth) Compression
Compression DefinedCompression Defined
The process of removing or restructuring data to decrease file size.
Display SizeDisplay Size
640 X 480Full Screen
320 X 240 240 X 180
160 X 120
Display SizeDisplay Size
DV default screen size is
720 X 480
Display size determines overall number of pixels.
720x480
345,600 pixels
Video RateVideo Rate
Number of captured video framesdetermines overall file size.
More Frames
Larger Files
Aspect RatioAspect Ratio
NTSC
4 units
3 units
16 units
9 units
DIGITAL STANDARD
Audio Capture RateAudio Capture Rate
MoreAudioData
LargerVideoFiles
Color ModelColor Model
320 X 240
Pixel depth (color planes) alsodetermines overall files size.
YUV9 - 9 bit color
RGB24 - 24 bit color
Compression IdealCompression Ideal
Ideally, compression must achieve a balance between controlling data rate and maintaining picture quality.
Camera Compression Camera Compression for DVfor DV
DV camera CODECs apply approximately a 5:1 ratio of compression to control file size.
Video Capture RateVideo Capture Rate
Capture
Rate
SmoothPlaybac
k
FileSize
Balance
ForOptimum
Acquiring Video FilesAcquiring Video Files
Possibilities!Possibilities!
Capture from analog camera or tape sources
Transfer from digital sources (i.e. “Firewire”)
Video clip collections Other output from software packages
Animators, screen captures, etc.
Acquisition SchemesAcquisition Schemes
Analog “Tape”
Video to Capture CardAudio to Sound Card
Digitize by Card
Set screen sizeSet # of framesSet file formatSet compressionSet audio parameters
Storage
Analog “Capture”
Transfer Protocol for DVTransfer Protocol for DV
DigitalDevice
“Firewire”IEEE 1394
Transfer Card
Video FileTo Disk
Acquisition SchemesAcquisition Schemes
Digital “Tape”
Firewire to CardSource provides Digital signalsCard only transfers
Storage
Digital “Transfer”
Acquisition SchemesAcquisition Schemes
Various “Levels” Of Firewire Cards
Storage
Digital “Transfer”
Firewire to Card•Apply various formats •Some mild compression •Software attributes
Card CostsCard Costs
Analog Digital
$200 & Higher $75 and Higher
DV Format AdvantagesDV Format Advantages
High Quality Video & Sound No “generation” loss from
analog/magnetic medium combination
No capture card settings International Standards Approach
Typical Digital FormatsTypical Digital Formats
Tape Video Quality Class
MiniDV Digital
4:1:1
High Consumer,
Prosumer
Digital-8 Digital
4:1:1
High Prosumer, Industrial
DV Digital
4:2:2
High Professional
MiniDV & Digital 8 MiniDV & Digital 8 Misc. Spec’sMisc. Spec’s 400-500 +/- lines of resolution 720 X 480 frame size 29.97 frame rate Audio
4 channels of 12 bit @ 32 kHz
2 channels of 16 bit @ 44 or 48 kHz
IEEE 1394IEEE 1394
International Standard Transfer Device Only
Usually some associated software Cable and card handle two-way
transfer Picture and sound Device Control Time Code
IEEE 1394IEEE 1394
Serial Device Transfer Rates up to 400 million
bits/ Will be even faster in the future!
“Firewire” by Apple 4 to 6 connector
“I-Link” by Sony 4 to 4 connector
QualityQuality
Frame Rate & Resolution
Bigger FilesMore Bandwidth
Higher Quality Image
Less Data, Faster Renders
Tradeoff
Analog to DigitalAnalog to Digital
An analog to digital (and digital to analog) conversion can often time be made via wires!
Wrap UpWrap Up
Knowing the specifications for both audio and video formats are important as you produce and distribute final media products.
Digital video is an excellent media for creating and editing but also will monopolize hard drive space!
content & curriculumcontent & curriculumcreated bycreated by
Dr. Mark MortensenDr. Mark MortensenUniversity of North TexasUniversity of North Texas
Copyright C. Mark Mortensen 2002