2005/12/06 1

Fast Intermode Decision in H.264/AVC Video Coding

D. Wu , F. Pan , K. P. Lim , S. Wu , Z. G. Li ,

X. Lin , S. Rahardja , and C. C. Ko

老師 : 楊士萱 博士學生 : 陳柏源 碩二

22005/12/06

Outline (1/1) H.264 encoder configuration Macroblock Partition Intermode Decision in H.264/AVC Fast Intermode Decision method Fast Intermode Decision Algorithm Experimental Results Reference

ave. Timesaving : 30%ave. PSNR loss : 0.03 dB

32005/12/06

H.264 encoder configuration (1/1)

Figure 1. Encoder configuration

Fn(current)

F'n-1(reference)

ME

MC

Intraprediction

ChooseIntra

predition

F'n(reconstructed)

Filter

T Q ReorderEntropyencode

T -1 Q -1

Dn X

D'n

Inter

Intra

P

uF'n

NAL

(1 or 2 previouslyencoded frames)

42005/12/06

Macroblock Partition (2/1)

Figure 2. Frame partitions Figure 3. Macroblock partitions

16

16

8x16 16x8 8x8

8x8

16x16

4x8 8x4 4x4

52005/12/06

Macroblock Partition (2/2)-blocksize selection={16x16 , 8x16 , 16x8 , 8x8 , 4x8 , 8x4 , 4x4}

Figure 4. QCIF ( News)

Figure 5. CIF (Paris)

62005/12/06

Intermode Decision in H.264/AVC (3/1) -blocksize selection={16x16 , 8x16 , 16x8 , 8x8 , 4x8 , 8x4 , 4x4}

Fn(current)

F'n-1(reference)

ME

MC

Intraprediction

ChooseIntra

predition

F'n(reconstructed)

Filter

T Q ReorderEntropyencode

T -1 Q -1

Dn X

D'n

Inter

Intra

P

uF'n

NAL

(1 or 2 previouslyencoded frames)

Figure 6. Encoder configuration

72005/12/06

Intermode Decision in H.264/AVC (3/2)

MV : )(.))(,(),( pmRmcsSADmJMOTIONMOTION

reference fram

search area

current frame

current macroblockbest match

Figure 7. Motion Estimation

Table 1. MPEG4 Motion VectorDifference (MVD)

82005/12/06

Intermode Decision in H.264/AVC (3/3)

Lagrangian Function :

SSD :

Lunda :

R(s,c,MODE|QP) : Number of bits (MODE & QP)

)|,,(.)|,,(),|,,( QPMODEcsRQPMODEcsSSDQPMODEcsJMODEMODE

8,8

1,1

28,8

1,1

2

16,16

1,1

2

])|,,[],[(])|,,[],[(

])|,,[],[()|,,(

yxVV

yxUU

yxYY

QPMODEyxyxQPMODEyxyx

QPMODEyxyxQPMODEssSSD

cscs

cs

PMODE

QP

PMODEx

QP

x

,

3

,))

6,4min(,2max(

85.0 2 For P-fram

For B-fram

92005/12/06

Method (3/1)-Homogenity (Sobel edge detection)

Edge vector : Vertical :

Horizontal :

Amplitude :

Homogeneous decision :

ppppppdx jijijijijijijixx

1,11,1,11,11,1,1,22

ppppppdyjijijijijijiji

xx1,1,11,11,1,11,1,

22

-1 0 1

-2 0 2

-1 0 1

-1 -2 -1

0 0 0

1 2 1dydxD jijijiAmp

,,,)(

NxNjiHji

NxNjiHji

cr

THdD

THdDH

Ampif

Ampif

,,

,,

,

)(,0

)(,1

},{,,, dydxD jijiji

102005/12/06

Method (3/2)-Stationary

Sum of absolute diff. :

Stationary :

16,16

1,1

]),[],[(ji

jiNjiMabsDiff

TT

S

S

Diffif

DiffifStationary

....,0

....,1

112005/12/06

Method (3/3) -blocksize selection={16x16 , 8x16 , 16x8 , 8x8 , 4x8 , 8x4 , 4x4}

Figure 8. QCIF ( News)

Figure 9. CIF (Paris)

122005/12/06

Algorithm (1/1)16x16 : THdH=20,0008x8 : THdH=5000

Ts=200

8x16 16x8 8x8

8x8

16x16

4x8 8x4 4x4

Category Corresponding Modes

MD 1

MD 2

MD 3

16X 16 , 16X 8 , 8X 16

8x8 , 8x4 , 4x8 , 4x4

8x8

16X16

MD 4

Decompose into four 8-by-8 subblocks

All four subblocksare checked ?

END

Best(MD2,3,4) Best(MD2)

YES

NO

YES

YES

YESNO

NO

No

MB is homogeneous ?

MB zero motion ?

MB , Diff <Ts ?

8x8 is homogenous ?

No

YES

YES

Best(MD1)Best(MD3)Best(MD4)

Save(MD2)

Edge detection , histogram

Start

132005/12/06

Experimental Results (4/1)

SeuqenceTime(%

)

Psnr(%)

Bits(%)

Foreman(QCIF) -25.18 -0.062 1.28

News(QCIF) -42.62 -0.065 1.18

Container(QCIF) -36.25 -0.012 0.3

Silent(QCIF) -45.16 -0.022 0.47

Paris(CIF) -31.9 -0.04 0.87

Mobile(CIF) -9.97 -0.005 0.13

Stefan(CIF) -17.37 -0.015 0.33

SeuqenceTime(%

)Psnr(%) Bits(%)

Foreman(QCIF) -24.61 -0.05 1.15

News(QCIF) -40.52 -0.029 0.54

Container(QCIF) -39.05 -0.027 0.45

Silent(QCIF) -45.92 -0.055 1.21

Paris(CIF) -26.54 -0.04 0.91

Mobile(CIF) -9.21 -0.002 0.06

Stefan(CIF) -16.31 -0.015 0.35

TABLE IIResults For IBBP Sequences

TABLE IResults For IPPP Sequences

142005/12/06

Experimental Results (4/2)

QP TypeTime(%

)

Psnr(%)

Bits(%)

28 IPPP -10.96 -0.01 -0.01

32 IPPP -10.04 -0.01 -0.02

36 IPPP -9.26 0.01 0.17

40 IPPP -9.54 0.00 0.28

TABLE IIIResult For “Mobile” (IPPP)

TABLE IVResult For “Mobile” (IBBP)

QP TypeTime(%

)

Psnr(%)

Bits(%)

28 IBBP -10.19 -0.02 0.03

32 IBBP -9.07 -0.01 0.04

36 IBBP -8.85 -0.01 -0.72

40 IBBP -8.66 0.00 -0.08

152005/12/06

Experimental Results (4/3)

Figure 10. News (IPPP) Figure 11. Mobile (IPPP)

162005/12/06

Experimental Results (4/4)

Figure 12. News (IBBP) Figure 13. Mobile (IBBP)

172005/12/06

Reference

D. Wu , F. Pan , K. P. Lim , S. Wu , Z. G. Li , X. Lin , S. Rahardja , and C. C. Ko, “ Fast Intermode Decision in H.264/AVC Video Coding “, IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 15, NO. 6,JULY 2005