研究生：李明峰指導教授：蔣依吾 博士

中山大學資訊工程學系 http://image.cse.nsysu.edu.tw/

H.264 畫框層級之快速模式決策方法

Outline

• H.264/AVC

• Mode Decision

• Frame-Based Fast Mode Decision Method

• Experimental Results

H.264/AVC

Description

Advantage & Disadvantage

H.264/AVC Description

JVT Joint Video TeamH.264/AVC

JVT Joint Video TeamH.264/AVC

ITU-TVCEG Video Coding Experts GroupH.264

ITU-TVCEG Video Coding Experts GroupH.264

ISO/IECMPEG Moving Picture Experts GroupMPEG-4 Part-10AVC Advanced Video Coding

ISO/IECMPEG Moving Picture Experts GroupMPEG-4 Part-10AVC Advanced Video Coding

MPEG-4MPEG-4MPEG-1

H.264/AVC Description

• 2003/5 final drafting completed

• 2005/3 Fidelity Range Extensions

MPEGStandards

JointITU-T/MPEG

Standards

ITU-TStandards H.261H.261 H.263 H.263+ H.263++H.263++

H.262MPEG-2

H.262MPEG-2 H.264H.264

1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

1990 2000

MPEG-1

ITU-T

ISO / IEC

H.261

MPEG-4

H.263

Part 2

Part 10

H.26L

AVCSame High level of commonality

Proprietary Real Video, WMV, On2, Divix, …

SMPTE VC-9

++ H.264

MPEG-2

H.262

JVT

H.264/AVC Description

Advantage

Resolution

Bit rates

Broadcast

DVD storage

RTP/IP packet networks

multimedia telephony systems

Good video qualityLow bit rates

Flexibility

High Profile High 10 High 4:2:2 High 4:4:4

Disadvantage • Complexity

編碼時間mv_search

block

refbuf

macroblock

rdopt

biariencode

cabac

memcpy

Mode Decision

Intra-mode decision

Inter-mode decision

Mode Decision

• Block Base

• Intra-mode

• Inter-mode

Intra-Mode Decision

Intra-Mode Decision

16*16 plane

4*4 horizontal

Intra-Mode Decision

原圖

處理後的圖

Inter-Mode Decision

Current Frame

Reference Frames

Inter-Mode Decision

方塊位置

Current Frame

Reference Frame

Motion Vector

巨區塊

B

C

B

CC

B

分成兩個 16*8 的區塊

A A A

不分割

Inter-Mode Decision

0

Sub macroblocktypes

4*4

0

1

0 1

0 1

2 3

0

8*8 8*4 4*8

0

1

0 1

0

2

1

3

16*16 16*8 8*16 8*8

Macroblocktypes

Mode Decision

Frame-Based Fast Mode Decision Method

Flow Description

The Method

前置處理

H.264 處理

演算法本體

概念圖

Current frameCurrent frame

Previous framePrevious frame

MB 的模式MB 的模式

概念圖

前置處理

H.264 處理

演算法本體

分群分群

正規化正規化

分群

最高細節度高細節度中細節度低細節度最低細節度

m4 m5 m1 m3

4*4Block SNR的平均值

4*4sub macro block

SNR

Previous framePrevious frame

Current frame

5 frames

Current frame

Previous framePrevious frame4 Pixels

5 frames

Frame DifferenceFrame DifferenceFrame DifferenceFrame DifferenceFrame Difference

5 frame differences

Frame DifferenceFrame DifferenceFrame DifferenceFrame DifferenceFrame Difference

53 54 37 42

53 47 40 36

49 44 33

47 46

38 57

63 72

59 70 74

71 60 69 75

58 68 65 70 76

41

5 frame differences

Frame DifferenceFrame DifferenceFrame DifferenceFrame DifferenceFrame Difference

53 54 37 42

53 47 40 36

49 44 33

47 46

38

41

34 67 58 83

34

57

63 72

59 70 74

71 60 69 75

58 68 65 70 76

Frame Difference

52 54 33 40

53 47 34 35

48 44 33

44 43

36

38

49

52 43

43 46 36

61 45 47 38

56 47 45 38 34

對所有值加以平均，得到 m1 值

m3

m1

m5

m4

m2

中細節度

最高細節度

高細節度

最低細節度

低細節度

Frame Difference

52 54 33 40

53 47 34 35

48 44 33

44 43

36

38

49

52 43

43 46 36

61 45 47 38

56 47 45 38 34

正規化

0

Sub macroblocktypes

4*4

0

1

0 1

0 1

2 3

0

8*8 8*4 4*8

0

1

0 1

0

2

1

3

16*16 16*8 8*16 8*8

Macroblocktypes

正規化細節

高細節

低細節

低細節

低

細節高

細節高

細節高

細節高

巨區塊

A

B

C

A

BB

C

C

A

分成兩個 16*8 的區塊

不分割

最佳解的可能性

C

輸出

高細節度

中細節度

低細節度

最高細節度

高細節度

中細節度

低細節度

最低細節度

Experimental Results

JM10.2 Fast mode decision

Compared with JM

JM10.2 Fast mode decision

• Homogeneous Regions DeterminationEdge detection (Sobel operator)

• Stationary Regions DetectionSAD (previous MB and present MB)

30

31

32

33

34

35

36

37

38

39

1 2 3 4 5 6

JM10.2

Proposed

0

500

1000

1500

2000

2500

1 2 3 4 5 6

JM10.2

Proposed

0102030405060708090

100

1 2 3 4 5 6

JM10.1

Proposed

ME timeME time

SnrYSnrY BitRateBitRate

FFMD FFMD

FFMD