Topic: Advanced Video Coding Standard (Comparison of HEVC with H.264 and H.264 with MPEG-2) A PROJECT UNDER THE GUIDANCE OF DR. K. R. RAO COURSE: EE MULTIMEDIA PROCESSING, SPRING 2015 SUBMITTED BY JAGRITI DHINGRA UT ARLINGTON ID: ID: 1

ATSC: Advanced Televisions Systems Committee AVC: Advanced Video Coding. BD-BR: Bjontegaard Delta Bitrate. BD-PSNR: Bjontegaard Delta Peak Signal to Noise Ratio. CABAC: Context Adaptive Binary Arithmetic Coding. CTB: Coding Tree Block. CTU: Coding Tree Unit. CU: Coding Unit. DBF: De-blocking Filter. DCT: Discrete Cosine Transform. DVB: Digital Video Broadcast HEVC: High Efficiency Video Coding. HM: HEVC Test Model. ICME: International Conference on Multimedia and Expo IEC: International Electro-technical Commission. ISDB: Integrated Services Digital Broadcasting ISO: International Organization for Standardization. TABLE OF ACRONYMS 2

ITU-T: International Telecommunication Union- Telecommunication Standardization Sector. JCT: Joint Collaborative Team. JCT-VC: Joint Collaborative Team on Video Coding. JM: H.264 Test Model. JPEG: Joint Photographic Experts Group. MC: Motion Compensation. ME: Motion Estimation. MPEG: Moving Picture Experts Group. MSE: Mean Square Error. PB: Prediction Block. PSNR: Peak Signal to Noise Ratio. QP: Quantization Parameter SAO: Sample Adaptive Offset. SSIM: Structural Similarity Index. TB: Transform Block. TU: Transform Unit. VCEG: Visual Coding Experts Group. 3

Typical structure of an H.264/MPEG4-AVC video encoder.[1] Figure 1 4

Advanced Video Coding H.264 or MPEG-4 Part 10, Advanced Video Coding (MPEG-4 AVC) is a video compression format that is currently one of the most commonly used formats for the recording, compression, and distribution of video contentvideo compression format H.264 is perhaps best known as being one of the video encoding standards for Blu-ray Discs; all Blu-ray Disc players must be able to decode H.264.Blu-ray Discs It covers all common video applications ranging from mobile services and videoconferencing to IPTV, HDTV, and HD video storage.[2] The H.264iAVC design [3] supports the coding of video (in 42:O chroma format) that contains either progressive or interlaced frames, which may be mixed together in the same sequence. 5

In H.264/AVC, three profiles are defined. Baseline, Main and X The Baseline profile supports all features in H.264iAVC except the following two feature sets: Set 1: B slices, weighted prediction, CABAC, field coding and macroblock adaptive switching between frame & field coding. Set 2: SP and SI slices. Main profile does not support the Flexible Macroblock Ordering (FMO) feature which is supported by the Baseline profile. Profile X supports both sets of features on top of the Baseline profile, except for CABAC and macroblock adaptive switching between frame and field coding. 6

H.264 design is divided into two layers i.e. Network Abstraction Layer VAL) and Video Coding Layer (VCL). NAL formats the VCL layer data into a format that is suitable for transmission by variety of transport layers whereas VCL does the compression of video. The video coding layer of H.264iAVC is similar in spirit to other standards such as MPEG-2 Video. It consists of a hybrid of temporal and spatial prediction, in conjunction with transform coding. Fig. 1 shows a block diagram of the video coding layer for a macroblock. 7

Figure 2: H.264 Encoder Block Diagram[4] 8

Video compression picture types There are three types of pictures (or frames) used in video compression: I ‑ frames, P ‑ frames and B ‑ frames.[7]video compression An I ‑ frame is an 'Intra-coded picture', in effect a fully specified picture, like a conventional static image file. P ‑ frames and B ‑ frames hold only part of the image information, so they need less space to store than an I ‑ frame and thus improve video compression rates.[7] Figure 2: Video compression types[7] 9

A P ‑ frame ('Predicted picture') holds only the changes in the image from the previous frame. For example, in a scene where a car moves across a stationary background, only the car's movements need to be encoded. The encoder does not need to store the unchanging background pixels in the P ‑ frame, thus saving space. P ‑ frames are also known as delta ‑ frames.[7] A B ‑ frame ('Bi-predictive picture') saves even more space by using differences between the current frame and both the preceding and following frames to specify its content.[7] 10

H.264 standard The standard was developed jointly in a partnership of VCEG and MPEG, after earlier development work in the ITU-T as a VCEG project called H.26L. It is thus common to refer to the standard with names such as H.264/AVC, AVC/H.264, H.264/MPEG-4 AVC, or MPEG-4/H.264 AVC, to emphasize the common heritage. The standardization of the first version of H.264/AVC was to extend the original standard, the JVT then developed what was called the Fidelity Range Extensions (FRExt). These extensions enabled higher quality video coding by supporting increased sample bit depth precision and higher- resolution color information, including sampling structures known as Y'CbCr 4:2:2 (=YUV 4:2:2) and Y'CbCr 4:4:4.[2]YUV 4:2:2 The next major feature added to the standard was Scalable Video Coding (SVC). Specified in Annex G of H.264/AVC, SVC allows the construction of bitstreams that contain sub-bitstreams that also conform to the standard, including one such bitstream known as the "base layer" that can be decoded by a H.264/AVC codec that does not support SVC.[2]Scalable Video Codingcodec 11

HEVC standard High Efficiency Video Coding (HEVC) [12] is an international standard for video compression developed by a working group of ISO/IEC MPEG (Moving Picture Experts Group) and ITU-T VCEG (Video Coding Experts Group). The main goal of HEVC standard is to significantly improve compression performance compared to existing standards (such as H.264/Advanced Video Coding [9]) in the range of 50% bit rate reduction at similar visual quality.[8] Figure 4: Block Diagram of HEVC CODEC [12] 12

MPEG-2 MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar disks. [10] The video section, part 2 of MPEG-2, is similar to the previous MPEG-1 standard, but also provides support for interlaced video; the format used by analog broadcast TV systems. MPEG-2 video is not optimized for low bit- rates, especially less than 1 Mbit/s at standard definition resolutions. However, it outperforms MPEG-1 at 3 Mbit/s and above. MPEG-2 is directed at broadcast formats at higher data rates of 4 Mbps (DVD) and 19 Mbps (HDTV).[11] 13

Table 1 is a tabulated form of the properties of the various MPEG-2 profiles. [13] 14

Table 2. MPEG-2 Levels [13] 15

Future Work Further I will be comparing the different video coding standards using Comparison metrics and using HEVC Test Model i.e. HM Software. 16

References [1] IEEE Communications Magazine August 2006 [2] [3] Thomas Weigan4 Gav J. Sullivan, Gistle Bjontegaard, and Ajay Luthra: "Overview of H.264 / AVC Video Coding Standard" in IEEE Transactions OD Circuits and System for Video Technology, vol. 13, issue 7, pp , July, [4] International Symposium on Communications and Information Technologics 2004 (ISCIT 2004 ) Sappom, Japan, October ,2004. [5] MPEG-2 video codec, Computer Science DivisionEECS, Univ. of Calif. at Berkeley. [6] Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG, Joint Model Reference Software Version 4.2 [7] [8] G.J. Sullivan et al, “Standardized Extensions of High Efficiency Video Coding (HEVC)”, IEEE Journal of selected topics in Signal Processing, Vol. 7, No. 6, pp , Dec

References [9] W.B. Pennebaker and J.L. Mitchell, JPEG: Still image data compression standard, Kluwer academic publishers, [10] “MPEG-2”, Wikipedia, Feb. 14, Available at [11] “H.262 : Information technology - Generic coding of moving pictures and associated audio information: Video”, International Telecommunication Union, [12] “Video coding for low bit rate communications,” ITUT, ITU-T Recommendation H.263, ver. 1, [13] “MPEG-2 White paper”, Pinnacle Technical Documentation, Version 0.5, Pinnacle Systems, Feb. 29, [14] [15]