High performance hardware architectures for Intra Block Copy and Palette Coding for HEVC Screen Content Coding extension

Transcription

1 High performance hardware architectures for Intra Block Copy and Palette Coding for HEVC Screen Content Coding extension Rishan Senanayake 1, Namitha Liyanage 1, Sasindu Wijeratne 1, Sachille Atapattu 1, Kasun Athukorala 1, P.M.K. Tharaka 1, Geethan Karunaratne 1, R.M.A.U. Senarath 1, Ishantha Perera 1, Ashen Ekanayake 1 and Ajith Pasqual 2 1 Paraqum Technologies, Colombo, Sri Lanka 2 Department of Electronic and Telecommunication Engineering University of Moratuwa, Sri Lanka ASAP 2017, The 27th Annual IEEE International Conference on Application-specific Systems, Architectures and Processors Screen Content Coding extension ASAP / 23

2 Outline 1 Background 2 Approaches 3 Novelties 4 Intra Block Copy 5 Palette Coding 6 Results 7 Conclusion Screen Content Coding extension ASAP / 23

3 Background H.265, introduced in 2013 achieves around 50% compression efficiency compared to H.264 Mainly targets camera captured content Modern videos include text, graphical motion and animations too Extension to HEVC = HEVC Screen Content Coding (HEVC-SCC) finalized in 2016 HEVC-SCC achieves about 50% efficiency over HEVC for synthetic content Screen Content Coding extension ASAP / 23

4 Features of Synthetic Content Large uniformly flat areas Repeated patterns Highly saturated areas Use of limited colors in an area Numerically identical blocks HEVC-SCC introduces Intra Block Copy (IBC) and Palette Coding (PLT) in addition to conventional transformation based coding Screen Content Coding extension ASAP / 23

5 Examples : Gaming Screen Content Coding extension ASAP / 23

6 Examples : Console Sharing Screen Content Coding extension ASAP / 23

7 Examples : Navigation Screen Content Coding extension ASAP / 23

8 Examples : Desktops Screen Content Coding extension ASAP / 23

9 Challenge 50% bit rate reduction... But Encoding time increases by more than 2x Screen Content Coding extension ASAP / 23

10 Approaches SCC test model (SCM) approach - developed for testing and evaluating of the standard Reduce complexity through pruning and low complexity estimating Hash based speed ups by Kuo et.al and Tsang et.al. Search area reduction by Tsang et.al. Optimizing K-means clustering by Saegusa et.al and Winterstein et.al. = Novel hardware based architectures proposed for IBC and Palette coding Screen Content Coding extension ASAP / 23

11 Novelties Novel Three stage architectures for IBC and palette coding New Hash Table to reduce resource usage by 8 times Palette sorting architecture used in palette comparisons Alternate coding approach to code palette syntax in parallel for Rate-Distortion (RD) cost estimation Screen Content Coding extension ASAP / 23

12 Intra Block Copy Copies the content from a previously coded similar block Challenge = Identifying best block Screen Content Coding extension ASAP / 23

13 Architecture Screen Content Coding extension ASAP / 23

14 Hash Optimization...Proposed scheme reduces table size by a factor of 8 Screen Content Coding extension ASAP / 23

15 Palette Coding Sending of color values of each pixel using indices Screen Content Coding extension ASAP / 23

16 Palette Coding Screen Content Coding extension ASAP / 23

17 Results - IBC 11% coding overhead compared to SCM encoder Screen Content Coding extension ASAP / 23

18 Results - Palette 5% coding overhead compared to SCM encoder Screen Content Coding extension ASAP / 23

19 Comparison Total = 66K LUTs Total = 51K LUTs Prototype implementations were synthesized for Xilinx VC707 platform igh performance hardware architectures for Intra Block Copy and Palette Coding for HEVC creen Content Coding extension ASAP / 23

20 Conclusion Hardware solutions are suitable for real time encoding of 1080p 30fps for HEVC-SCC Significant amount of hardware resources can be saved with a slight coding overhead These novel architectures can be added to existing HEVC hardware encoders to support HEVC-SCC profile Future work will be on easy adaption of these architectures to existing HEVC encoders Screen Content Coding extension ASAP / 23

21 References I SCM Software repository Available : Accessed April 2017 C.-W. Kuo, H.-M. Hang, and C.-L. Chien Intra block copy hash reduction for hevc screen content coding Signal and Information Processing Association Annual Summit and Conference (APSIPA) 2016 S.-H. Tsang, Y.-L. Chan, and W.-C. Siu Hash based fast local search for intra block copy (intrabc) mode in hevc screen content coding Signal and Information Processing Association Annual Summit and Conference (APSIPA), 2015 Screen Content Coding extension ASAP / 23

22 References II S.-H. Tsang, W. Kuang, Y.-L. Chan, and W.-C. Siu Fast hevc screen content coding by skipping unnecessary checking of intra block copy mode based on cu activity and gradient. Signal and Information Processing Association Annual Summit and Conference (APSIPA) 2016 T. Saegusa and T. Maruyama Real-time segmentation of color images based on the k-means clustering on fpga. International Conference on Field-Programmable Technology, Dec 2007 F. Winterstein, S. Bayliss, and G. A. Constantinides Fpga-based k-means clustering using tree-based data structures. 23rd International Conference on Field programmable Logic and Applications Screen Content Coding extension ASAP / 23

23 Thank you Screen Content Coding extension ASAP / 23