Hardware Implementation of Transform & Quantization Blocks in H.264/AVC Video Coding Standard By: Hoda Roodaki Instructor: Dr. Fakhraei Custom Implementation of DSP Systems Class Seminar. All materials are copy rights of their respective authors as listed in references In the Name of God

Outline Video Coding & Standardization Video Coding Standards & Application H.264/AVC (MPEG-10) Standard H.264 Drawbacks Proposed Method for 4x4 DCT, 8x8 DCT and Quantization Concolusion 2

Video Coding & Standardization Efficient digital representation of video signals has been the subject of considerable research over the past twenty years. Visual communications has become more feasible Availability of digital transmission links Progress in signal processing VLSI technology Video compression research Increased commercial interest in video communications Standardization 3

Video Coding Standards & Application Moving Picture Experts Group (MPEG) MPEG1 ( ) – Audio and video on storage media such as CDROM MPEG2 (1993) – Digital TV: SDTV, HDTV MPEG4 (1994) – A standard for very low bit rate coding of limited complexity audio-visual material ITU-T Video Coding Expert Group (VCEG) H.261 ( ) – Videoconferencing, video- telephone applications over ISDN telephone lines H.263 (1996) – mobile network 4

H.264/AVC (MPEG4-part10) Standard In 2001 With the aim of developing a more efficient compression system, MPEG VSEG Joint Video Team (JVT) 5

H.264/AVC (MPEG-10) Standard Significant improvement in coding efficiency – Average bit rate reduction of 50% given fixed fidelity compared to any other video standard Error robustness Applications Broadcast over cable, satellite, cable modem, DSL, terrestrial. Interactive or serial storage on optical and magnetic storage devices, DVD, etc. Conversational services over ISDN, Ethernet, LAN, DSL, wireless and mobile networks, modems. Video-on-demand or multimedia streaming services over cable modem, DSL, ISDN, LAN, wireless networks. Multimedia messaging services over DSL, ISDN. Broad range of bit rates and picture sizes ranging from very low bit rate, low frame rate video for mobile and dial-up devices through to entertainment-quality standard- definition television services, HDTV, and beyond. 6

H.264 Drawbacks These aggressive compression techniques increase computational complexity and need an efficient architecture to implement these techniques Quantization & Transformation blocks are two critical parts of encoder We need some methods that simplifies these blocks Real Time Applications 7

Proposed Method for 4x4 DCT [1] The forward 4x4 DCT of a sample block 8

Proposed Method for 4x4 DCT(Cont.) 9

BFa 10 [1]

Proposed Method for 4x4 DCT(Cont.) 11

Proposed Method for 4x4 DCT Evaluation 12

Proposed Method for 4x4 DCT Evaluation 13 Synthesized with Xilinx Project Navigator for Xilinx Virtex 5 (xc5vlx30). Typical Implementation Typical Implementation Proposed Method DCT (9 bits)DCT/Quant (16 bits) 3737 gatesDCT block requires 294 gates 65 FFs 256 bits R/W memory 7000 gates

Proposed Method for 8x8 DCT [2] Initial H.264 specification adopted an integer approximation of 4×4. But the 4×4 block is not enough higher resolutions 8x8 DCT Significant Compression Performance Additional Complexity 14

Proposed Method for 8x8 DCT(Cont.) 15

Proposed Method for 8x8 DCT(Cont.) The 2-D forward 8x8 – 1-D horizontal (row) transform – 1-D vertical (column) transform 16

Proposed Method for 8x8 DCT(Cont.) 17

Proposed Method for 8x8 DCT(Cont.) 18

Proposed Method for 8x8 DCT(Cont.) 19

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Proposed Method for 8x8 DCT(Cont.) Architecture of Proposed Algorithm [2] 23

Proposed Method for 8x8 DCT(Cont.) 1-D Transform Block [2] 24

H.264 Quantization 25 Qstep?

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Proposed Quantization Block Architecture 27 [2]

Proposed Method for 8x8 DCT & Quantization - Evaluation In the architecture – Each input column vector of 8 pixels is input to the 1-D DCT block for 8 cycles => 64 cycles are required to process all pixel elements in one 8×8 block – Without multiplication – The pixel by pixel processing can remove redundant modules processing in integer transform block and quantization block. – Quantization block is designed to cover all multiplication factors without using a real multiplier. 28

Proposed Method for 8x8 DCT & Quantization - Evaluation Parallel Implementation Proposed method Critical path delay (ns) Clk frequency Parallelism641 Latency164 The target device chosen is Xilinx Virtex-II Pro XC2VP30 FPGA. 29 [2] 90% area reduction in Proposed Method

Conclusion The continuing development of digital video coding has produced H.264/MPEG-4 (Part 10) Advanced Video Coding. It provides gains in compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards Besides, network friendliness and good video quality at high and low bit rates are important features that distinguish H.264 from other standards. These advantages are paid with a considerably higher need of computational complexity. 30

Conclusion To implement DCT and quantization blocks for H.264, many efforts have been carried out. 4x4 DCT => a method without any multiplication – less complex and definitely faster than typical method 8x8 DCT => a pipeline method Without multiplication for DCT & Quantization – Less complex and less area than parallel method but slower 31

References [1] Nandi, S.; Rajan, K.; Biswas, P. “Hardware implementation of 4×4 DCT/quantization block using multiplication and error-free algorithm”, TENCON [2] Jeoong Sung Park; Ogunfunmi, T. “A New Hardware Implementation Of The H.264 8×8 Transform And Quantization”, IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP [3] Mohammad Norouzi, Karim Mohammadi, Mohammad Mahdy Azadfar,” Multiplication and Error Free Implementation of H.264 like 4x4 DCT/Quan_IQuan/IDCT using Algebraic Integer Encoding”, IJCSNS International Journal of Computer Science and Network Security, VOL.6 No.9B, September [4] Iain E G Richardson, “H.264 / MPEG-4 Part 10 White Paper : Transform & Quantization”, vcodex, [5] Thomas Wiegand, Gary J. Sullivan, Gisle Bjontegaard, and Ajay Luthra, “Overview of the H.264 / AVC Video Coding Standard”, IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, JULY [6] Thomas Sikora,” Digital Video Coding Standards and Their Role in Video Communications”, Signal Processing for Multimedia. J.S. Byrnes (Ed.) IOS Press,

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