H.264 / MPEG-4 Part 10 Nimrod Peleg March 2003

Encoder .. bit stream - image sequence 0101... + Q VLC M.C. DCT Q VLC -1 MEM M.C. - Intra / Inter switch M.E. .. image sequence 0101... bit stream

Encoder .. bit stream - image sequence 0101... + Q VLC M.C. DCT Q VLC -1 MEM M.C. - Intra / Inter switch M.E. .. image sequence 0101... bit stream

Encoder .. bit stream - image sequence 0101... + Q VLC M.C. DCT Q VLC -1 MEM M.C. - Intra / Inter switch M.E. .. image sequence 0101... bit stream

Encoder .. bit stream - image sequence 0101... + Q VLC M.C. DCT Q VLC -1 MEM M.C. - Intra / Inter switch M.E. .. image sequence 0101... bit stream

Encoder .. bit stream - image sequence 0101... + Q VLC M.C. DCT Q VLC -1 MEM M.C. - Intra / Inter switch M.E. .. image sequence 0101... bit stream

Previous Standards

H.264 Brief review Goal Start from zero. No backward compatibility. Develop a high-performance video coding standard. Start from zero. No backward compatibility. Assumptions Block based. Software implementation. Network friendly.

H.264 Encoder .. - Image sequence Intra/Inter Switch Coding control 0101... bit stream + IDCT Q Entropy Coder -1 Frames Store M.C. - Intra/Inter Switch M.E. .. Image sequence Coding control

Transform DCT like. Integer arithmetic only. without multiplications. Optional use of a 4x4 transform block size.

Quantization Compounding quantization step. Thirty-two different quantization step sizes. The step sizes are increased at a compounding rate of approximately 12.5%. Different quantizer for luminance, chrominance. Two different coefficient-scanning patterns. The simple zigzag scan. The double scan.

Frames Store The H.264 standard offers the option of having multiple reference frames in inter picture coding. Up to five different reference frames could be selected. Resulting in better subjective video quality and more efficient coding of the video frame under consideration. Using multiple reference frames might help making the H.264 bit-stream error resilient.

Motion Estimation & Compensation Motion Estimation is where H.264 makes most of its gains in coding efficiency. Quarter pixel accurate motion compensation. Translation only. The standard does not determine which algorithm should be used.

Motion Estimation & Compensation Seven optional modes. Different modes of dividing a macroblock for motion estimation in H.264

Entropy Coding H.264 has adopted two approaches for entropy coding : Universal Variable Length Codes (UVLCs) One table. Context-Based Adaptive Binary Arithmetic Coding (CABAC)

Intra prediction 9 optional prediction modes for each 4x4 luma block. 4 optional modes for a 16x16 luma block. 4 optional prediction modes for a 8x8 chroma component. One mode for 4x4 chroma block.

Summery Transform Quantizer Motion estimation and compensation IDCT Optional use of a 4x4 transform block size. Quantizer step sizes are increased at a compounding rate of approximately 12.5%. Two coefficient-scanning patterns. Motion estimation and compensation Translation only. A number of different block sizes are used for motion prediction. Quarter pixel positions are used for motion prediction.

Summery Frames store Entropy coding Multiple reference frames may be used for prediction. Entropy coding Only one regular VLC is used for symbol coding.