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Top1. Introduction
Over the past two decades, digital video compression techniques have played a vital role in processing visual data. This is due to the spreading of various multimedia applications in the recent time. Mobile TV, Digital Video Broadcasting (DVB), Local Area Network (LAN) video streaming, video surveillance cameras, high resolution digital cameras, hand-held multimedia phones, Personal Digital Assistant (PDA), ultra-low power video sensors, and Digital Versatile Disk (DVD) are some examples of such applications. Due to the exponential increase in the required Megapixels per second (Mpbs) of the previous multimedia applications, video data compression is considered as a hot area nowadays.
H.264/AVC (Advanced Video Coding) and H.265/HEVC or High Efficient Video Coding standards (JVT, 2003, 2012; Ohm, Sullivan, Schwarz, Thiow Keng, & Wiegand, 2012) are the most recent recommendations that are greatly remove data redundancies from the transmitted video signal. As a result, the required transmission bit-rate is greatly reduced. H.264/AVC standard is finalized by ITU and ISO in 2003 (JVT, 2003). Many compression techniques are used by the H.264/AVC standard under a constrain of keeping high coding efficiency. High coding efficiency means high visual quality as well as low transmission bit-rate. A savings of up to 50% in the transmitted bit rate can be achieved by the H.264/AVC standard compared to all of its previous standards. This allows the H.264/AVC standard to be used in many applications such as video conferencing, video-on-demand, and video streaming. Keeping this high reduction in bit-rate and still high video quality is achieved in such standard by using many time exhaustive and computational complexity tools such as multiple reference frames, half-pel and quarter-pel accurate motion estimation, and variable block sizes. Such tools may slow down the use of such H.264/AVC standard in real time video applications.
Recently, high resolution videos become high demanding in popularity (Davis & Marikkannan, 2014). However, sending such high resolution videos over the current network infrastructure is a challenge. This is because the huge bit-rate required for transmitting such huge video data. H.265/HEVC or High Efficiency Video Coding (HEVC) standard has been originally developed and finalized by ITU-T VCEG and ISO/IEC MPEG (JVT, 2012; Ohm et al., 2012). The H.265/HEVC standard achieves two main goals. First, encoding the high resolution video such as 4K and Ultra High Definition (UHD) using lower bit-rate compared to all other previous standards. Second, utilizing parallel processing operations in order to avoid the delay results from the added tools that are used to lower the bit-rate. The main raised issue in H.265/HEVC standard is that the computational complexity has been dramatically increased compared to previous standards. H.265/HEVC encoder is four-time more complex than older standards (Bossen, Bross, Suhring, & Flynn, 2012).