A high-performance and high-precision sub-pixel motion estimator-interpolator for real-time HDTV(8K) in MPEGH/HEVC coding

摘要

Despite increased complexity sub-pixel motion estimation and compensation significantly outperforms integer motion estimation and compensation in HEVC/MPEGH/H.265 Video Codec's, since moving objects do not necessarily move by integer pixel locations between successive video frames. Typically, fractional pixel accuracy is obtained by means of bilinear interpolation producing a spatially blurred predicted signal. The motion estimation and compensation is improved in this paper by means of the filtering effect using a very effective spatial digital low pass FIR filter, which allows the motion vectors to be determined with higher levels of precision and accuracy than existing algorithmic implementations. The fractional pixel accuracy was achieved using a total of 112 8-tap digital FIR filter for one-eighth pixel precision, which includes half and quarter pixel accuracy. The design has been implemented on a 28nm foundry process, with a speed of 1.101 GHz and it has achieved 2262 GOPS at this speed, outputting data at the rate of 1.8 Tera bits per second, for one-eighth pixel accuracy. Computational complexity, Memory & I/O Bandwidth has been reduced by inputting the Mean Square Error Map of the pixels to the Fractional Pixel Estimator and then searching in the sub-pixel grid. This design is targeted for 8K Ultra High Definition Television (UHDTV). 8K HDTV format is 8192 × 4320 pixels. This amounts to 35.4 Million Pixels per Frame. The incoming Video Pixel Rate for 8K HDTV at 60 Frames per Second (fps) is 2.12 Billion Pixels per Second or 2.12 Giga Pixels / second. This amounts to an incoming Video Data Rate of 51 Billion bits per second or 51 Gbps. At 120 frames per second the Incoming Video Pixel rate is 4.24 Billion Pixels per Second or 4.24 Giga Pixels per Second. This amounts to incoming Video Data Rate of 102 Gbps. For Quarter Pixel Motion Estimation, we are adding 3 Sub-Pixels for every Integer Pixel. Pixel Count increases by a factor of 16. For 4K HDTV this becomes 142 Million Pixels per Frame. At 60fps, the Pixel rate is 8.5 Billion Pixels per Second or 8.5 Giga Pixels per Second, with a Video Processing Data Rate of 195 Gbps. At 120fps the Pixel rate 17 Billion Pixels per Second or 17 Giga Pixels / Second, with a Video Processing Data Rate of 390 Gbps. For 1/8th Pixel Motion Estimation, we are adding 7 Sub-Pixels for every Integer Pixel. Pixel Count increases by a factor of 64. For 8K HDTV this becomes 570 Million Pixels per Frame. At 60fps, the Pixel rate is 34 Billion Pixels per Second or 34 Giga Pixels / Second, Video Processing Data Rate of 780 Gbps. At 120fps the Pixel rate 70 Billion Pixels per Second or 70 Giga Pixels / Second, Video Processing Data Rate of 1560 Gbps / 1.56 Tbps.