Video Compression Lecture # 5 6 Shahab Baqai LUMS Outline Image - - PowerPoint PPT Presentation

CS 584 / CMPE 584 Multimedia Communication

Video Compression

Lecture # 5 – 6

Shahab Baqai LUMS

2

Outline Image compression

– Transform, uniform quantization, Huffman coding

Video compression

– Exploit temporal dimension of video signal – Motion-compensated prediction – Generic (MPEG-type) video coder/decoder architecture

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Video Compression

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Temporal Processing

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Video Compression

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Temporal Processing

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Temporal Processing: Motion Estimation

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Block-Matching Motion Estimation

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Block Matching: Determining the Best Matching Block

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Example of Fast Search: 3-Step (Log) Search

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Motion Vector Precision?

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Practical Half-Pixel Motion Estimation Algorithm

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Example: MC-Prediction for Two Consecutive Frames

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Example: MC-Prediction for Two Consecutive Frames (cont.)

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Block Matching Algorithm: Summary

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Bi-Directional MC-Prediction

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MC-Prediction and Bi-Directional MC-Prediction (P- and B-frames)

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Video Compression

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Example Use of I-,P-,B-frames: MPEG Group of Pictures (GOP)

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Summary of Temporal Processing

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Basic Video Compression Architecture

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Example Video Encoder

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Example Video Decoder

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Blocks & Macro Blocks

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Blocks & Macro Blocks (4:2:2) & (4:4:4) Formats