КОДИРОВАНИЕ С НЕРАВНОЙ ЗАЩИТОЙ КОМПРЕССИРОВАННОГО ВИДЕО В БЕСПРОВОДНЫХ СЕТЯХ

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  • 5, 2013 69

    - - [1]. - , - . -, - -, , , QoS (Quality of Service) . -, - . -, - . -, -, -, - . , - , - , - . -

    ( QoS-) - .

    - - . , - - (. , [26]). , - , , - [46]. - - - , - .

    , - -, - . - , -

    621.397

    . . , . , . . ,-

    , - ( ) . - - (RA-), . - , , , - RA-.

    , , /, - , -.

  • 5, 201370

    - -, - .

    , - - HEVC (High Efficiency Video Coding) [7], - - H.264/AVC. - , HEVC-, - , , - , H.264/AVC, - (. 1): - () VCL (Video Coding Layer) - NAL (Network Abstraction Layer), - - .

    VCL ( H.264/AVC) , , - -. - - GoP (Group of Pictures) - , - -. - , . , -; - - . , - , -

    (CTB Coding Tree Block) (. 2, ). , CTB (TU Transformation Unit) (. 2, ). , -, HEVC , - , ( H.264/AVC).

    , - , - I- () P- () . I- - , P- - , I- () P-. , I- , P-.

    NAL , - - (, RTP (Real-time Transport Protocol)). NAL - , -, VCL, .

    (VCL)

    (NAL)

    . 1.

    . 2. - HEVC: - CTB; - CTB TUs ( )

    )

    )

  • 5, 2013 71

    - NAL, NALU (NAL Unit), , - . NALU, , . NALU -, . NAL , .

    . , H.320 H.324, (. 3), - . - , -

    RTP/IP TCP/IP, NAL - - . NAL .

    , , . HEVC- ( H.264/AVC) - (Data Partition Mode) (A, B C) - , -. , , - , NAL-, NAL-A, NAL-B NAL-C . - NAL-A - , NAL-B NAL-C - (. 4).

    CTB

    . 3.

    CTB

    Intra (AC/DC ), Intra

    , Inter Inter (AC/DC )

    DC

    MV

    NAL-A

    NAL-B

    NAL-

    . 4.

    RoHC

    NALU-

    VCL/CABAC-

    NALU-IP/UDP/RTP-

    RTP-

    (MAC)

    (LLC)

    . 5.

  • 5, 201372

    - - . 5. - . RoHC (Robust Header Compression) .

    Data Partition Mode - A, B C ( ) - , - . - -, , HEVC-.

    - HEVC- - , :

    1) (, / , -), , - ;

    2) , - , - ;

    3) . -

    , , DC- AC- . - -

    . RTP- NAL. , - , . 6, .

    , -, , - L, GoP. , GoP , GoP, - GoP. , P- I- GoP, - P- - . , GoP ( - -), , - GoP - GoP. , - GoP, . 7, .

    - - . , , - ( ) - . , , . , , .

    - - HEVC- Data Partition Mode. A ( A) :

    . 6. , (); - (); () ()

    ) ) ) )

  • 5, 2013 73

    1) ;2) GoP;3) ;4) (Intra

    Inter);5) .

    ( B) :1) -

    ;2)

    Intra Inter ( );3)

    (Intra). C

    ( C) :

    1) (Inter);

    2) ;3) -

    Intra Inter;

    4) - .

    , I- . -, , , , - RTP- NAL. -, - - L GoP , I- P-. , , , . - B, C. - - ) - A A ) -

    . 7. , : GoP; 4 ( ); 12; 20; 28

    1. A, B C Foreman

    , %,

    R = 1500 / R = 1700 /

    L = 4 L = 8 L = 16 L = 32 L = 4 L = 8 L = 16 L = 32

    A 1,29 0,75 0,36 0,16 1,20 0,73 0,36 0,35

    B 51,36 39,74 44,07 52,73 53,31 42,16 44,36 40,94

    C 47,35 59,51 55,57 47,11 45,49 57,11 55,28 58,71

    ) ) )

    ) )

  • 5, 201374

    B C B C . . 1 , - A, B C Foreman. CIF (352 288 , 8 , YCbCr 4:2:0) f = 30 /c.

    , A GoP, B C - . -, , B < C, - , . , - L = 16 (. 2), - - B

  • 5, 2013 75

    , - RA- - (Belief Propagation BP), -.

    - . 9. , - , -, - A, B C Data Partition Mode. , -, - . - , kA, kB kC -, - n. - - RA- , - .

    rA = kA/n, rB = kB/n rC = kC/n RA-, - A, B C -. , , - R(A/rA +B/rB +C/rC).

    , , - / (Peak

    Signal-to-Noise Ratio PSNR), PSNR = 10log10(255/D) [], D ( ) . - D - , -, -. - - , -, . , - , - . , D DS +DC, DS , , DC , [1214], - D - DS DC. [12] , - DS - R :

    DS = D0 +(RR0), (1)

    D0, R0 , - , - GoP I-. . 10 (1) - - DS Foreman.

    , - ,

    A

    B

    C

    A

    B

    C

    RA-

    . 9.

  • 5, 201376

    . - - DC - [12] , . -, I- ( ) 2I , - ( - GoP)

    ( ) ( )1

    2I I I

    01 1/ ,

    L

    ej

    n P j L j-

    = - + (2)

    nI , I-; Pe - ; I, I[0, 1] , - - . - DC - .

    1. ( GoP), .

    2A, 2B

    2C -

    ; , 2A( , 2B,

    2C)

    - - .

    2. - , - A, B C.

    2A, 2B

    2C :

    -

    =- -

    = =

    - b +

    +

    -b -+

    - +

    12 2A IA

    IA01 1

    2PA

    PA1

    11

    1 11 1

    /

    /;

    L

    j

    L L

    l j l

    j Lj

    j lL j

    (3)

    - - -

    = = =

    - -b - b +

    + - + 1 1 1

    2 2 2B IB PB

    IB P0 1

    1 1 11 1 1

    / /;

    L L L

    j l j l

    j L j lj L j

    (4)

    - - -

    = = =

    - -b - b +

    + - + 1 1 1

    2 2 2C IC PC

    IC PC0 1

    1 1 11 1 1

    / /,

    L L L

    j l j l

    j L j lj L j

    (5)

    b , - I- ;

    2IA ( ) -

    I-, A; 2PA - ( ) P-, - A ( - 2IB,

    2PB,

    2IC

    2PC ).

    - DC, ,

    2 2 2A A A B B B C C C ,C e e e

    RLD P P P

    f + + (6)

    f -; PeA, PeB, PeC A, B C -.

    RA- - - . - () Pe 104 109 Pe / h []

    Pe exp10[u(r, n)h +v(r, n)], (7)

    u(r, n) v(r, n) r n RA-. , - RA- r = 1/2 n = 1024 u(r, n) v(r, n) 5,1 9,6 -.

    (1), (6) (7), -:

    ( )0 02 2 2

    A A A B B B C C C ,e e e

    D D R R

    RLP P P

    f

    + - +

    + + + (8)

    1000 1200 1400 1600 1800 2000 2200

    20

    25

    30

    35

    40

    D

    S

    R, /

    . 10. DS (1) Foreman

  • 5, 2013 77

    PeA exp10[u(rA, n)h +v(rA, n)], PeB exp10[u(rB, n)h +v(rB, n)], PeC exp10[u(rC, n)h +v(rC, n)],

    2A, 2B

    2C

    (3), (4) (5) . (8) -

    - . - GoP L, R rA, rB rC , -; S = (L, R, rA, rB, rC). - S, - / h (8) - . -, V -, . . R(A/rA +B/rB +C/rC) V. -, n - RA- , , . , - -, [15], - .

    , PSNR - , - ( - ). - - -. - - Foreman Wi-Fi - V = 2 /. , - -, . n = 1024, rA, rB rC , - , {s/(s +1)|1 s 9}. PSNR

    , - , . 11. - PSNR, ) - , ) - ) -, - ( PSNR). . 11 . -, / h > 10,5 , RA- -0,50 . -, - 4 . -, / h 0 , - 1,1 2,3 .

    - ( . 11) - , - - . - -, - .

    2 0 2 4 6 8 10 1210

    15

    20

    25

    30

    35

    40

    45

    PSN

    R,

    / h ,

    PSNR

    . 11. PSNR / ( Foreman, - V = 2 /)

  • 5, 201378

    600 800 1000 1200 1400 1600 1800 200010

    15

    20

    25

    30

    35

    40

    45

    ,

    280 300 320 340 360 380 400 42010

    15

    20

    25

    30

    35

    40

    45

    ,

    120 140 160 180 200 220 24010

    15

    20

    25

    30

    35

    40

    45

    ,

    PSN

    R,

    P

    SNR

    ,

    PSN

    R,

    . 12. PSNR - ( Foreman, V = 2 /): ; - ;

    . - #3 - , ( -). -, 2,412 , - 10 , 1, - () - -174 1 , - -101 20 .

    , PSNR -, . 12, . , - - . . -, - PSNR 30 ( MOS) ( - ) , - -. -, #2 #3 ( - ) - -, #1. , - PSNR = 30 #1 1000 - 400 - , - #2 #3 110 40 .

    - , - - ( - ) - . - - - (RA-), - , - -, --. -

    )

    )

    )

    [16]. #1 , - -. #2 - : , -

  • 5, 2013 79

    , ) - , ) - ) -/ , , - . Foreman , PSNR ( ) 4 . , , -

    - 1,1 2,3 / h 0 . PSNR - - - . , - PSNR = 30 38 137 % - 11 27 % .

    1. Cai L., Shen X., Mark J. W. Multimedia Services in Wireless Internet: Modeling and Analysis. Wiley, 2009. 290 p.

    2. Nafaa A., Taleb T., Murphy L. Forward Error Correc-tion Strategies for Media Streaming over Wireless Networks // IEEE Communication Magazine. Dec. 2007. P. 7279.

    3. Xiao J., Tillo T., Lin C., Zhao Y. Real-Time Forward Error Correction for Video Transmission // Proc. of IEEE Conf. on Visual Communications and Image Pro