An Approach to Selective Intra Coding and Early Inter Skip Prediction in H.264/AVC Standard

Transcription

1 FACTA UNIVERSITATIS (NIŠ) SER.: ELEC. ENERG. vol. 21, no. 1, Aprl 2008, An Approach to Selectve Intra Codng and Early Inter Skp Predcton n H.264/AVC Standard Zoran Mlčevć and Zoran Bojkovć Abstract: Ths paper presents selectve ntra codng and early nter skp fast mode decson algorthm for H.264/AVC and compares performance of H.264/AVC wth pror standards. Vdeo codng standard H.264/AVC provdes gans n compresson effcency of up to 50% over a wde range of bt rates and vdeo resolutons compared to prevous standards. In order to acheve ths, a robust rate-dstorton optmzaton (RDO) technque s employed to select best codng mode and reference frame for each macroblock. Also, the orgnal and modfcaton test models are compared for combned skp and ntra predcton method n H.264/AVC encoder, when B pctures are analyzed. Expermental results show that the codng tme s reduced by 35-42% through early dentfcaton of macroblocks that are lkely to be skpped durng the codng process and through reducng the number of canddate modes. Keywords: Early nter skp predcton, Selectve ntra predcton mode decson, MPEG-2, MPEG-4 part 2, Wndows Meda Vdeo 9, Audo Vdeo Codng Standard (AVS). 1 Introducton The H.264 vdeo codng standard has the same basc functonal elements as prevous standards (MPEG-1, MPEG-2, MPEG-4 part 2, H.261, H.263) [1 3],.e., transform for reducton of spatal correlaton, quantzaton for bt rate control, moton compensated predcton for reducton of temporal correlaton and entropy encodng for reducton of statstcal correlaton. However, n order to fulfll better codng performance, the mportant changes n H.264 occur n the detals of each Manuscrpt receved on September 9, Z. Mlčevć s wth the Telecommuncaton and IT Department GS of the SAF, Raska 2, Belgrade, Serba (e-mal: mmlcko@eunet.yu). Z. Bojkovć s wth the Unversty of Belgrade, Bulevar Nkole Tesle 38, Belgrade, Serba (e-mal: zbojkovc@yahoo.com). 107

2 108 Z. Mlčevć and Z. Bojkovć: functonal element by ncludng ntra-pcture predcton, a new 4x4 nteger transform, multple reference pctures, varable block szes, a quarter pel precson for moton compensaton, a deblockng flter, and mproved entropy codng. Improved codng effcency comes at the expense of added complexty to the coder/decoder. H.264 utlzes some methods to reduce the mplementaton complexty. The mprovement n codng performance comes manly from the predcton part. Intra predcton sgnfcantly mproves the codng performance of H.264/AVC ntra frame coder. On the other sde, nter predcton s enhanced by moton estmaton wth quarter-pxel accuracy [4], varable block szes, multple reference frames [5] and mproved spatal/temporal drect mode. Unlke the prevous standards, predcton must be always performed before texture codng not only for nter macroblocks but also for ntra macroblocks [6]. Ths paper s organzed as follows. The short overvew of H.264/AVC standard s presented n secton II. Secton III explans selectve ntra codng and early nter skp algorthm and gves expermental results. Secton IV concludes the work. 2 Overvew of H.264/AVC The coded output btstream of H.264/AVC has two layers, Network Abstracton Layer (NAL) and Vdeo Codng Layer (VCL) [7]. NAL abstracts the VCL data n a manner that s approprate for conveyance on a varety of communcaton channels or storage meda. The VCL unt contans the core vdeo coded data, whch conssts of vdeo sequence, pcture, slce, macroblock and block. H.264/AVC use follow codng tools [8]: Intra spatal (block based) predcton: Full-macroblock (16 16) luma or chroma predcton 4 modes (drectons) for predcton and 8 8 (FRExtonly) or 4 4 luma predcton 9 modes (drectons) for predcton; Inter temporal predcton block based moton estmaton and compensaton: Mult reference pctures, Reference B pcture, Arbtrary referencng order, Varable block szes for moton compensaton (seven block szes: 16 16, 16 8, 8 16, 8 8, 8 4, 4 8 and 4 4, 1 / 4 sample luma nterpolaton ( 1 / 4 or 1 / 8 th-sample chroma nterpolaton), Weghted predcton, Frame or Feld based moton estmaton for nterlaced scanned vdeo; Interlaced codng features: Frame-feld adaptaton (Pcture Adaptve Frame/Feld (PcAFF) and MacroBlock Adaptve Frame Feld (MBAFF)) and Feld scan; Lossless representaton capablty: Intra PCM raw sample-value macroblocks and Entropy-coded transform-bypass lossless macroblock (FRExtonly);

3 An Approach to Selectve Intra Codng (FRExt-only) or 4x4 Integer Inverse Transform (conceptually smlar to the well-known DCT); Resdual color transform for effcent RGB codng wthout converson loss or bt expanson (FRExt-only); Scalar quantzaton; Encoder-specfed (FRExt-only); perceptually weghted quantzaton scalng matrces Logarthmc control of quantzaton step sze as a functon of quantzaton control parameter; Deblockng flter (wthn moton compensaton loop); Coeffcent scannng: Zg-Zag (Frame) and Feld; Lossless Entropy codng: Unversal Varable Length Codng (UVLAC) usng Exp-Golomb codes, Context Adaptve VCL (CAVLC), Context-based Adaptve Bnary Arthmetc Codng (CABAC); Error Reslence Tools: Flexble Macroblock Orderng (FMO), Arbtrary Slce Order and Redundant Slces; SP and SI synchronzaton pctures for streamng and other uses; Varous color spaces supported (YCbCr of varous types, YCgCo, RGB, etc. especally n FRExt); 4:2:0, 4:2:2 (FRExt-only), and 4:4:4 (FRExt-only) color formats. H.264/AVC defnes a set of seven Profles, each supportng a partcular set of codng functons and each specfyng what s requred of an encoder or decoder that comples wth the Profle. Also, profles are defned to cover the varous applcatons from the wreless networks to dgtal cnema. There are three Profles n the frst verson: Baselne, Man and Extended. Baselne profle s to be applcable to real-tme conversatonal servces such as vdeo conferencng and vdeophone. Sutable applcaton for the Man Profle ncludes broadcast meda applcatons such as dgtal televson and stored dgtal vdeo. Extended profle s amed at multmeda servces over Internet [7]. Also there are four Hgh Profle defned n the Fdelty range extensons for applcatons such as content-contrbuton, content-dstrbuton, and studo edtng and post-processng: Hgh, Hgh 10, Hgh 4:2:2 and Hgh 4:4:4. Snce a profle defnes a set of codng tools or algorthms that can be used n generatng a complant btstream, a level places constrants on certan key parameters of the btstream. In 2004 Jont Vdeo Team (JVT) added new extensons known as the Fdelty Range Extensons (FRExt) [8], whch provde a number of enhanced capabltes

4 110 Z. Mlčevć and Z. Bojkovć: relatve to the base specfcaton. Specfcally, these nclude: supportng an adaptve block-sze for the resdual spatal frequency transform, supportng encoderspecfed perceptual-based quantzaton scalng matrces, and supportng effcent lossless representaton of specfc regons n vdeo content. Also, the Scalable H.264/AVC extenson s appled to extend the hybrd vdeo codng approach of H.264/AVC n a way that a wde range of spatal-temporal and qualty scalablty s acheved [9]. It refers to scalablty as a functonalty that allows the removal of parts of the bt-stream whle achevng a reasonable codng effcency of the decoded vdeo at reduced temporal, SNR, or spatal resoluton. H.264/MPEG 4-AVC has receved a great deal of recent attenton from ndustry. Besdes the classcal applcaton areas of vdeoconferencng and broadcastng of TV content (satellte, cable, and terrestral), the mproved compresson capablty of H.264/MPEG 4-AVC enables new servces and thus opens new markets and opportuntes for the ndustry. Another area that has attached a lot of nearterm ndustry mplementaton nterest s the transmsson and storage of HD content [10]. H.264 can be appled to consumer equpment such as dgtal cameras, cell phones, vdeo-over-ip networks, and hgh-defnton dgtal broadcastng through terrestral or satellte channels, and dgtal storage system such as hgh-defnton DVD [7]. Today H.264/AVC enable IPTV over DSL, because the H.264/AVC standard lets telephone companes (telcos) deploy broadcast-and DVD-qualty vdeo content over ther exstng DSL-based IP access networks to help them effectvely compete wth cable and wreless operators [11]. Table 1 compares the codng algorthms of H.264 wth MPEG-2 and MPEG-4 part 2. As t can be seen the advantage of usng H.264/MPEG-4 part 10 s evdent when codng tools are taken nto account. Other codng standards such as Wndows Meda Vdeo 9 (WMV-9) [12] and AVS Chna [13] are brefly compared too (Table 2). 3 Selectve Intra Codng and Early Inter Skp Algorthm In the open lterature the optmal mode (mode decson) for a macroblock s selected as that whch produces the least RD cost. The H.264 standard employs a brute force algorthm to search through all possble block-szes to fnd a moton vector for each macroblock. Thus, the computatonal burden of the searchng process s far more demandng than any exstng vdeo codng algorthm. A fast ntra mode decson algorthm for H.264/AVC ntrapredcton by usng local edge nformaton s proposed n [14]. It s observed that the pxel along the drecton of local edge are normally of the smlar values (ths s true for both luma and chroma components). A good predcton could be acheved f the pxels are

5 An Approach to Selectve Intra Codng Table 1. Comparson of standards MPEG-2, MPEG-4 part 2, and H.264 / MPEG-4 part 10 [7]. Feature/Standard MPEG-2 MPEG-4 part 2 MPEG-4 part 10/H.264 Macroblock sze (frame mode) 16 8 (feld mode) Block Sze , 16 8, , 8 16, 16 8, 8 8, 4 8, 8 4,4 4 Intra-predcton No Transform doman Spatal doman Transform 8 8 DCT 8 8 DCT/Wavelet 8 8, 4 4 nteger DCT transform 4 4, 2 2 Hadamard Quantzaton Scalar quantzaton Vector quantzaton Scalar quantzaton wth step wth step sze of szes of ncrease at the rate of constant ncrement 12.5% Entropy codng VLC VLC VLC, CAVLC and CABAC Pel accuracy 1 / 2 -pel 1 / 4 -pel 1 / 4 -pel Reference pcture One pcture One pcture Multple pctures Forward/forward Bdrectonal Forward/backward forward/backward Forward/backward predcton mode forward/forward Weghted predcton No No Yes Deblockng flter No No Yes Pcture Types I, P, B I, P, B I, P, B, SI, SP Profles 5 profles 8 profles 7 profles Playback & Yes Yes Yes Random Access Error robustness Data parttonng Synchronzaton, Data parttonng, parameter FEC for mportant data parttonng, settng, flexble macroblock packet transmsson header extenson, orderng, redundant slce, SP reversble VLCs and SI slces Transmsson rate 2-15Mbps 64kbps - 2Mbps 64kbps150Mbps Encoder complexty Medum Medum Hgh Compatble wth Yes Yes No prevous standards predcted usng those neghborng pxels that are n the same drecton of the edge. Therefore, an edge map whch represents the local edge orentaton and strength s created, and a local edge drecton hstogram s then establshed for each subblock. Based on the dstrbuton of the edge drecton hstogram, only a small number of predcton modes are chosen for RDO calculaton durng ntrapredcton. Expermental results show that the fast mode decson algorthm ncrease the speed of ntra codng sgnfcantly wth neglgble loss of the qualty. In [15] a fast ntermode decson algorthm to decde the best mode n ntracodng s proposed. It makes use of the spatal homogenety and the temporal statonarty characterstcs of the vdeo objects. Specfcally, spatal homogenety

6 112 Z. Mlčevć and Z. Bojkovć: Table 2. Comparson of WMV-9 and AVS wth H.264/MPEG-4 part 10 [7]. Feature/Standard MPEG-4 part WMV-9 AVS 10/H.264 Predcton block sze 16 16, 8 16, 16 8, 8 8, 16 16, , , 8 4, 4 4 Intra-predcton 4 4, 8 8: 9 modes No 8 8: 5 modes 16 16: 4 modes Transform 8 8, 4 4 nteger DCT 8 8, 4 8, 8 4, 4 4 Asymmetrc , 2 2 Hadamard nteger DCT nteger DCT Quantzaton Scalar quantzaton Dead zone, unform Scalar quantzaton scalar quantzaton Entropy codng VLC, CAVLC and Multple VLC tables VLC CABAC Sub-pel flter 1 / 2 -pel: 6-tap, 1 / 2 -pel: 4-tap, 1 / 4 -pel: 4-tap, 1 / 4 -pel: 2-tap 1 / 4 -pel: 4-tap 1 / 4 -pel: 4-tap Reference pcture Multple pctures One pcture Two pctures Bdrectonal Forward/backward Forward/backward, Forward/backward, predcton forward/forward 2 moton vectors symmetrc 1 moton mode backward/backward, vector 2 moton vectors Weghted predcton Yes Yes Yes Deblockng flter Yes Yes Yes of a MB s decded based on the MBs edge ntensty, and temporal statonarty s decded by the dfference of the current MB and t collocated counterpart n the reference frame. Based on the homogenety and statonarty of the vdeo objects, only a small number of ntermodes are selected n the the RDO process. The expermental results show that the fast ntermode decson algorthm s able to reduce on the average 30% encodng tme, wth a neglgble peak sgnal-to-nose raton loss of 0,03 db or, equvalently, a bt rate ncrement of 0,6%. On the other sde a fast nter mode selecton algorthm was proposed n [16] to allevate the encoder complexty due to mode decson, whle mantanng pcture qualty and other codng effcency. The FInterms algorthm makes use of a spatal content measure to assgn dfferent levels of nter-modes to each macroblock dependng on ts complexty. The lower the complexty of the macroblock content, the fewer nter-modes the encoder has to check, and vce versa. The paper [17] seeks to provde an algorthm for fast codng mode selecton n H.264/AVC encoders by reducng the number of canddate modes. A rate estmaton method for further reducton of Lagrangan cost calculaton s presented, too. It s concluded that total computaton for mode selecton can be reduced sgncantly f the cost calculatons for less probable modes, e.g. ntra modes n very low moton vdeos, can be skpped. Also the computaton can be reduced further f

7 An Approach to Selectve Intra Codng R s estmated n the cost calculaton. To fnd the best codng parameters for each macroblock, H.264/AVC reference software encodes all possble combnaton of parameters and calculates the rate and dstorton of a gven macroblock for each combnaton. Ths means that the encoder calculates the R-D costs of all possble codng optons and chooses the codng mode of a gven macroblocks whch has mnmum R-D cost [18]. The modfcaton software verson wth algorthm appled reduces computatonal processng through early dentfcaton of macroblocks to be skpped [19]. Pror to codng each macroblock, the encoder estmates the rate-dstorton cost of codng or skppng the macroblock. Based on these estmates, the macroblock s ether coded as normal or skpped. Skp predcton model ams to reduce computaton whlst mantanng or mprovng rate-dstorton performance. To generate the problem we have mplemented one known skp predcton algorthm [20] for complex calculatons. Our research ncludes: Man profle wth correspondence tools, the skp algorthm only for B pctures and rate dstorton optmzaton mode selecton dsabled. We used the skp algorthm only for B pctures because, n comparson to pror vdeo-codng standards, the concept of B pctures s generalzed n H.264/AVC. Generally, B pctures utlze two dstnct reference pcture buffers, whch are referred to as the frst and second reference pcture buffer, respectvely. In B pctures, four dfferent types of nter-pcture predcton are supported: lst 0, lst 1, b-predctve, and drect predcton. If no predcton error sgnal s transmtted for a drect macroblock mode, t s also referred to as B slce SKIP mode and can be coded very effcently, smlar to the SKIP mode n P slces [10]. Let M be the codng mode (one of K possble modes) chosen by the encoder for macroblock X and let M = K denote the skp mode. The rate-dstorton cost of codng an macroblok s gven n whle costs of skppng a macroblock s [20]: J(X ) = D(X,M )+λr(x,m ) (1) J(X,K) = D(X K) (2) respectvely, where λ s a weghtng parameter (Lagrange multpler). Note that the rate assocated wth a skpped macroblock s effectvely zero. Macroblock X should be skpped (not coded) f D(X,M )+λr(x,m ) D(X),K) (3) D(X,K) s the dstorton between the current macroblok and the motoncompensated macroblok from the reference pcture wth zero dsplacement from

8 114 Z. Mlčevć and Z. Bojkovć: the predcted vector MVp. The dstorton measure s selected to be mean-squared error (MSE). D(X,K) may be calculated pror to codng the current macroblock,.e. ts calculaton does not depend on any outputs of the codng process. D(X,M) s the MSE between the current macroblock and the decoded, reconstructed macroblock whle R(X,M ) s the number of bts requred to code the current macroblock usng codng mode M {1,...,K 1}. The actual values of D(X,M ) and R(X,M ) are not avalable pror to codng, and thus these parameters are estmated for each macroblock n the current frame (n) usng the followng models ˆD (n) (X (n) ˆR (n) (X (n),m (n),m (n) ) =α d D (n 1) (X (n 1) ) (4) ) =α r R (n 1) (X (n 1) ) (5) D (n 1) (X (n 1) ) s the MSE between the orgnal and reconstructed macroblocks n the same poston n the prevous frame (n 1), whle R (n 1) (X (n 1) ) s the number of bts requred to code the macroblock n the same poston n the prevous frame and α d and α r are fxed parameters. The skp predcton algorthm proceeds as follows [20]: For every macroblock, calculate D n (X,K) and read prevously stored values D (n 1) (X (n 1) ) and R (n 1) (X (n 1) ). Calculate the actvty factor for the current macroblock F = D (n 1) (X (n 1) ) R (n 1) (X (n 1) Calculate ˆλ usng equaton (by substtutng F for F): ) (6) ˆλ = ( F )xe ( F )QP (7) Choose skp mode f the followng expresson s true: D (n 1) (X (n 1) )+0.5ˆλ R (n 1) (X (n 1) ) D (n) (X,K) (8) If skp mode s chosen, no further processng s carred out and the macroblock s marked as skpped. If code mode s chosen, process the macroblock as normal. H.264/AVC encodes the macroblock by teratng all the luma ntra decsons for each possble chroma ntra predcton mode for the best codng effcency. Number of mode combnatons for luma and chroma components n an macroblock s C8 (L L16), where C8, L4, and L16 represent the number of modes for

9 An Approach to Selectve Intra Codng chroma predcton, 4 4 luma predcton and predcton, respectvely. It means that, for an macroblock, t has to perform 4 ( ) = 592 dfferent RDO calculatons before a best RDO mode s determned. The key dea of the chose selectve ntra predcton mode decson methods for fast ntra mode decson stems from the fact that the domnatng drecton of a bgger block s smlar to that of smaller block [21]. The best predcton mode of 4 4 luma block wthn block has the same drecton as that of luma block. The computaton of the ntra predcton and the chroma predcton can be reduced on the base of the overall edge nformaton from the ntra predcton result. The 9 modes luma ntra predctons modes s assorted of the 4 4 block to make four canddate groups accordng to the drectonal nformaton of the predcton mode. Therefore the unlkely modes are fltered out pror to the RD cost computaton based on the drectonal correlaton between luma block and 4 4 luma block. Selectve ntra predcton mode decson method for 8 8 chroma ntra predcton modes s proposed for the enhancement of chroma ntra predcton. Even though the luma block and the chroma block are from lumnance sgnals and chromnance sgnals separately, they encode the same secton of mage, pxel macroblock, and share overall drectonal nformaton. The number of chroma predcton modes s narrow down from 4 modes to 2 modes, accordng to the best predcton mode of the luma block. In accordance wth prevous, the number of canddate modes for 4 4 luma block sze s decreased from 9 to 4-7 modes, whle luma block sze has same value (4 modes). The number of canddate modes for 8 8 chroma block sze s decreased from 4 to 1-2 modes. The number of mode combnatons for an macroblock s only 1 ( ) = 68 at the best case, whereas the current RDO calculaton n H.264/AVC requres 4 ( ) = Expermental results and dscusson Our experment envronment s based on modfcaton of H.264 reference encoder of JM 10.2 (modfcaton verson - JM10.2M), whch was developed by JVT [22]. Expermental results are tested wth the follow condtons: Man profle; MV search range has value 32; Quantzaton parameter has value 40; Number of reference frames s 5; Hadamard transform; CABAC; IBBP format; specfyng and coverng 6 vdeo sequences of the dfferent actvty, same resolutons (QCIF). All tests n the experment are run on the Pentum Intel 2.53 GHz, wth 512 MB RAM and the OS Mcrosoft Wndows XP. In our experments, we use the frst 50 frames of the dfferent test sequences.

10 116 Z. Mlčevć and Z. Bojkovć: The test sequences have been selected to emphasze dfferent knd of motons and contents, such as low-to-hgh amount of movement, camera zoomng and pannng moton and context wth complcated texture. We used for test 6 sequences n QCIF format (Clare, Coastguard, Contaner, Grandmother, News, Salesman). Our dea s to perform tests and compare dfferent test versons n order to show whch mprovements are obtaned by our verson JM 10.2M. In order to compare and to analyze the output results we choose the followng key factors: sgnal - to nose rato (SNR) for luma (Y) pcture component, the bt rate (kbps) and the computatonal tme (ms). Table 3 shows expermental results when both test software verson are used. Table 3. Expermental results. Test sequences Computatonal Tme (%) SNR (db) Bt rate (%) Clare Coastguard Contaner Grandmother News Salesman Average Table 3 shows the performance of the combned method (SKIP mode predcton and selectve ntra predcton decson) n B slces n the IBBP structure. When the number of reference frames s 5, the proposed method gves encodng tme savng from about 35% untl over 42%. The encodng tme n average s reduced over 38%. Ths means that the modfed H.264/AVC encoder s faster than reference software JM Fgure 1 shows computatonal tme reducton (curve wth romb dots marks orgnal, whle curve wth square dots marks modfcaton results for computatonal tme dependng on the number of pctures) for Contaner test sequence. Ths sequence was chosen because t gves the best performance of the Fg. 1. Computatonal tme for Contaner (QCIF) test sequence.

11 An Approach to Selectve Intra Codng proposed scheme n sense of computatonal savng tme. However, there s very neglgble loss n term SNR: t s only 0.03 (db) n average. On the other hand, our values for the bt rate are slghtly ncreased (from 0.53 to 2,87%). Table 4 summarzes the smulaton results for the several dfferent fast codng algorthms compared to our the best test sequence Contaner n terms of the computatonal tme, the bt rate and PSNR. It can be seen that the proposed algorthm gve the better results especally n term of computatonal savng tme. The obtaned results show that our JM10.2M algorthm acheves values over 60% n computatonal tme reducton n comparson to algorthms n [14] and [17], whle that dfferences are less for another two algorthms [15] and [16], but stll better. Table 4. Comparson results for the several dfferent fast codng algorthms Sequence Performance Algorthm Algorthm Algorthm Algorthm JM10.2M [14] [15] [16] [17] Tme (%) Contaner PSNR (db) Bt rate (%) Concluson Ths paper descrbes the man features of H.264/AVC standard and compare those features wth features of another vdeo codng standard (MPEG-2, MPEG-4 part 2) and especally wth Wndows Meda Vdeo 9 and AVS standards. Comparson s shown that H.264/AVC provdes better compresson, effcent codng of vdeo contents and approprate bt rates for equvalent perceptula qualty. Also, ths paper compares the two test models (orgnal and modfcaton) for combned skp and ntra predcton method n H.264 encoder, when B pctures are analyzed. Our expermental results ndcate that codng tme s reduced by 35-42% through early dentfcaton of macroblocks that are lkely to be skpped durng the codng process and through reducng the number of canddate modes. There s not sgnfcant loss of rate-dstorton performance. Codng tme s substantally reduced because a sgnfcant number of macroblocks are not processed by the encoder. References [1] T. Wegand, G. Sullvan, G. Bjontegaard, and A. Luthra, Overvew of the H.264/AVC vdeo codng standard, IEEE Trans. on Crcuts and System for Vdeo Technology, vol. 13, no. 7, pp , 2003.

12 118 Z. Mlčevć and Z. Bojkovć: [2] A. Pur, H. Chen, and A. Luthra, Vdeo codng usng the H.264/MPEG-4 AVC compresson standard, Sgnal Processng: Image Communcaton, vol. 19, pp , [3] I. E. G. Rchardson, H.264 and MPEG-4 vdeo compresson vdeo codng for nextgeneraton multmeda. The Atrum, Southern Gate, Chchester, West Sussex PO 19 8SQ, England: John Vley and Sons Ltd., [4] Y. W. Huang, B. Y. Hseh, T. C. Chen, and L. G. Chen, Analyss fast algorthm, and VLSI archtecture desgn for H.264/AVC ntra frame codng, IEEE Trans. on Crcuts and Systems for Vdeo Technology, vol. 15, no. 3, pp , Mar [5] Y. W. Huang, B. Y. Hseh, S. Y. Chen, S. Y. Ma, and L. G. Chen, Analyss and complexty reducton of multple reference frames moton estmaton n H.264/AVC, IEEE Trans. Crcuts and Systems for Vdeo Technology, vol. 16, no. 4, pp , Apr [6] M. Flerl and B. Grod, Generalzed B pctures and the draft JVT/H.264 vdeo compresson standard, IEEE Trans. on Crcuts and System for Vdeo Technology, vol. 13, no. 7, pp , [7] S. Kwon, A. Tamhankar, and K. R. Rao, Overvew of the H.264/MPEG-4 part 10, Journal of Vsual Communcaton and Image Representaton, vol. 17, pp , Apr [8] G. Sullvan, P. Topwala, and A. Luthra, Overvew of the H.264/AVC advanced vdeo codng standard: Overvew and ntroducton to the fdelty range extensons, n SPIE Conference on Applcatons of Dgtal Image Processng XXVII, Specal sesson on andvanced n the new emergng standard: H.264/AVC, Aug. 2004, pp [9] n Scalable vdeo codng WD 1, M. W. J.Rechel, H.Schwarz, Ed., Hong Kong, Jan. 2005, vol. Doc. VT-N020, Doc. VT-N020. [10] D. Marple, T. Wengard, and G. J. Sullvan, The H.264/MPEG4 advaced vdeo codng standard and ts applcatons, IEEE Communcaton Magazn, vol. 44, pp , Aug [11] [Onlne]. Avalable: H264 IPTV Over DSL.pdf [12] S. Srnvasan et al., Wndows meda vdeo 9: Overvew and applcatons, Sgnal Processng: Image Communcaton, vol. 19, pp , Oct [13] W. Gao et al., AVS The Chnese Next-Generaton Vdeo Codng Standard, Natonal Assocaton of Broadcasters Std., Apr [14] F. Pan, X. Ln, S. Rahardja, K. P. Lm, Z. G. L, D. Wu, and S. Wu, Fast mode decson algorthm for ntrapredcton n H.264/AVC vdeo codng, IEEE Trans. on Crcuts and System for Vdeo Technology, vol. 15, no. 7, pp , July [15] D. Wu, F. Pan, K. P. Lm, S. Wuand, Z. G. L, X. Ln, S. Rahardja, and C. C. Ko, Fast ntermode decson n H.264/AVC vdeo codng, IEEE Trans. on Crcuts and System for Vdeo Technology, no. 7, pp , July [16] A. Yu, Effcent block-sze selecton algorthm for nterframe codng n H.264/MPEG-4 AVC, n Proc. of IEEE Internatonal Conference on Acoustc, Speech and Sgnal Processng, vol. 3, Montreal, Canada, May 2004, pp [17] H. Km and Y. Altunbasak, Low-compexty macroblok mode selecton for H.264/AVC encoders, n Proc. of Internatonal Conference on Image Processng, vol. 2, Oct. 2004, pp [18] I. Cho, J. Lee, and B. Jeon, Fast codng mode selecton wth rate-dstorton optmzaton for MPEG-4 part-10 AVC/H.264, IEEE Trans. on Crcuts and System for Vdeo Technology, vol. 16, no. 12, pp , Dec

13 An Approach to Selectve Intra Codng [19] Z. Mlcevć and Z. Bojkovć, Computatonal tme reducton usng low complexty skp predcton for H.264/AVC standard, WSEAS Trans. on Informaton Scence and Applcatons, Issue 1, vol. 14, pp , Jan [20] C. S. Kannangara, I. E. G. Rchardson, M. Bystrom, J. R. Solera, Y. Zhao, A. MacLennan, and R. Cooney, Low-complexty skp predcton for H.264 through lagrangan cost estmaton, IEEE Trans. on Crcuts and Systems for Vdeo Technology, vol. 16, no. 2, pp , [21] J. S. Park and H. J. Song, Selectve ntra predcton mode decson for H.264/AVC encoders, Trans. on Engneerng, Computng and Technology, vol. 13, pp , [22] [Onlne]. Avalable: suehrng/tml/download/jm10.2