10 10.1 10.2 10.3 10.4 H.26110.5 H.2632010-2*

10.1 2010-2* - (, ) .

.

: , .

.

10.2 2010-2* .

(temporal redundancy) . () , .

(MC: Motion Compensation) 1. ( )2. 3. , ,

2010-2* NN (macroblocks) .

N = 16. 4:2:0 , N = 8.

.

(Target frame) . / ()( (Reference frame)() ) . MV . 10.1 , (forward prediction) .

2010-2* 10.1: MV [-p, p] .

(2p+1)(2p+1) .

10.3 (MAD: Mean Absolute Difference) :

N - ,k l - ,i j - ,C(x+k, y+l) - ,R(x+i+k, y+j+l) - .

MAD(i, j) , MV = (u, v) (i, j) .2010-2*

2010-2* (sequential search): (2p+1)(2p+1) .( (Full search) )

, MAD (10.1) .

MAD (i, j) MV(u, v) .

. (, , ) . (2p+1)(2p+1) N2 3 O(p2N2).

2010-2* 10.1 :

2 2010-2* (logarithmic search): .

2 .

10.2 , 9 MAD- ; 1 .

MAD , , -(step-size)((offset)) .

, 9 2 . .

2010-2* 10.2: 2

10.2 : 2 2010-2*

, :2010-2*

2010-2* (: multiresolution) .

10.3: 0 3- , 1 2 2 , 2 .

, p , .

2010-2* 10.3: 3-

() k (uk, vk) , k-1 (2uk ,2vk) 33 . (uk-1, vk-1) k-1 :

( , ) k . ( , ) :

2010-2* 10.3 :

2010-2* 10.1

10.4 H.2612010-2*H.261: , .

, ISDN .

p64kbps , p 1 30 .( p64 )

150msec , .

ITU & H.261 2010-2*H.261 ITU .

1. H.221 64 1,920kbps (audiovisual) .

2. H.230 .

3. H.242 .

4. H.261 p64kbps (encoder)/(decoder).

5. H.320 p64kbps (narrow-band) .

2010-2* 10.2 H.261

2010-2* 10.4: H.261

H.261 2010-2* : -(I-) -(P-):

I- . JPEG I- . .P- : .( P- I- )P- (temporal redundancy removal) , I- (spatial redundancy removal) . , I- .

H.261 15 . , P=15.

(I-)2010-2* Y 1616 . Cb Cr 4:2:0 88 . 88 4 Y , 1 Cb , 1 Cr . 88 DCT . DCT . 10.5: I-

(P-) 2010-2* 10.6 H.261 P- :

, .

, (difference macroblock) .

88 DCT, , , .

P- ( ) .

, . , .

( ), (non-motion compensated) .

MVD :2010-2*

2010-2* 10.6: H.261 P-

2010-2*H.261 H.261 DCT , _(step_size) .

DCT DCT QDCT , DC :

:

scale [1, 31]

H.261 2010-2* 10.7 H.261 .

I, P1 P2 .

: ( ) .

10.3 10.4 .

2010-2* 10.7: H.261

2010-2* 10.7(): H.261

2010-2* 10.3: H.261 10.4: H.261

H.261 2010-2*1. : PSC (Picture Start Code) . TR (Temporal Reference) - .

2. GOB : H.261 113 , GOB(Group of Blocks) .

10.9 CIF QCIF GOB .

, CIF 352288 26 GOB . GOB (GBSC: Start Code) (GN: Group Number) . 10.8 H.261 : 4 : , GOB, , .

2010-2* , H.261 (identifiable) GOB .

GQuant MQuant( ) , GOB .

3. : (MB) GOB , (MQuant) 6 88 (4Y, 1Cb, 1Cr) .

4. : 88 , DC AC 0-(Run) 0 (Level) , EOB(End of Block) . Run [0, 63]. Level . [-127, 127], level 0.

2010-2* 10.8: H.261

2010-2* 10.9: H.261 GOB

10.5 H.2632010-2*H.263 (PSTN: Public Switched Telephone Networks) .

64kbps .

- , (- - ) .

2010-2* 10.5 H.263

H.263 & GOB (Group of Blocks)2010-2*H.261 , H.263 GOB(Group of Blocks) .

H.263 GOB H.261 , .

10.10 , QCIF 9 GOB , GOB 111MBs (17616) . 4CIF 18 GOB , GOB 442MBs (70432) .

2010-2* 10.10: H.263 GOB

2010-2*H.263 MV() , MV1, MV2, MV3 .( 10.11(a) )

MV(u, v) :

MV(u, v) , ( , ) , .

2010-2* 10.11 H.263

- 2010-2* H.261 - (full-pixel precision) H.263 - (half-pixel precision) .

MV(u, v) u v [-16, 15.5].

10.12 , - (bilinear interpolation) .

2010-2* 10.12: H.263 -

H.263 2010-2*H.263 :1. :

.

, .

[-31.5, 31.5].

2010-2*2. - :

H.261 , H.263 DCT (VLC) .

H.261 , H.263 4 . .

3. :

, 16 8 .

4 (88 ) .

2010-2*4. PB- :

10.13 , H.263 PB- .

PB- PTYPE .

PB- .

, PB- B- . H.263 2 .

2010-2* 10.13: H.263 PB-

H.263+ H.263++2010-2*H.263+ : , , , .

H.263+ H.263 4 12 .

(RVLC: Reversible Variable Length Coding) .

(flexibility) GOB .

2010-2*H.263+ (Temporal), SNR (Spatial scalabilities) .

1 , B- P- PB- .

H.263+ (blocking effects) (deblocking filters) .

2010-2*H.263++ H.263 (ERRS :Enhanced Reference Picture Selection), (DPS : Data Partition Slice), .

ERPS - . (coding efficiency) (error resilience) .

DPS DCT .