Product Distribution Mediums, Strategies and Compression

Define & discuss compression schemes for video Identify common distribution mediums for video Discuss post-production strategies for product distribution Objectives

MiniDV & Digital 8 Signal Format DV 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

Software conversion after capture Less expensive Can be slower without hardware assist Many software CODEC’s available Two Approaches to Post Processing

Reduce Frame Size Reduce Frame Rate Reduce Audio Rate Apply Compression Reduce time in minutes Reducing File Size

Short for “compress/decompress” Similar to the word modem— modulate/demodulate CODEC software is mostly for compression but may also do some formatting CODEC

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

LosslessLossy Keeps All BitsRemoves Bits Two Types: Compression

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

Frame Most modern CODEC’s use a combination of spatial and temporal compression within between Compression Concepts

Keyframe Compression Key Frame 1 Delta Frame 1 Delta Frame 2 Delta Frame 3 All Saved Difference from Key Frame 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

Software compression time variables CODEC Compression Ratios CPU horsepower Length in minutes Amount of change (i.e. 30 frames to 15) Compression Concepts

CODECS Sorenson Cinepac Indeo RLE Video 1 MPEG Compression Concepts

DV million bits/second 5:1 ratio of compression Intra-Frame 4:1:1 Color Videotape CD-ROM DVD Streaming Media Where to Go?

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

Size limitation! Approx 650 megs Change video parameters to fit project on CD CD-ROM Frame size # of frames etc

Output file Format selection MPEG-2 would show if System had hardware card Make Movie …

Choose CODEC Make Movie …

Change Audio Parameters Make Movie …

Settings for finished project Make Movie …

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 DVD

Export directly to streaming format if available Prepare file, then export to streaming media Streaming Media

Class lectures – 320X frames Highest quality compression as possible Process through Real Producer Streaming Media

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