Sumit Johar

Adding SVC Spatial Scalability to Existing H.264/AVC Video

This paper describes an innovative algorithm for adding SVC Spatial Scalability to all existing non-scalable H.264/AVC video streams. The algorithmic system builds on a full-decode-full-encode method of conversion and employs reuse of available data by an efficient downscaling of video information for different layers, thus reducing the complexity of the algorithm by manifold whilst maintaining a high coding efficiency. The complexity is further reduced by bypassing of various time consuming processes of the encoding process by the use of sharing and reuse of video information coming from original bitstream. Extensive analysis has been done to evaluate the gains in the coding efficiency and complexity of the algorithm using the full-decode-full-encode approach as a benchmark. The ultimate reduction in complexity is at least 60% from full-decode-full-encode while maintaining the output video quality. The modular nature of the algorithm is designed to be easily adaptable to other scalable video standards as well.

Hardware architecture for real time H.264 CABAC decoding for HDTV applications

H.264 or AVC (Advanced Video Coding) is a latest digital video codec standard which was developed as an answer to the growing demand for better compression in a wide range of applications and for improved network friendliness. H.264 is able to deliver a compression efficiency of up to 50% over a wide range of bit rates and video resolutions compared to previous standards (e.g. MPEG2 or H.263). The downside is that the H.264 decoder complexity is nearly four times higher than the previous standards. Hence a powerful hardware platform is required to provide real-time performance of H.264 in todays high-end applications like HDTV. We present an innovative Hardware architecture to perform real-time H.264 CABAC decoding using Finite State Machines (FSMs) for decoding of syntax elements. This architecture delivers a throughput of 1 bin per cycle @ 180MHz as reported by Synopsys Design Compiler.

Transcoding Compressed Video Signals to WMV9

This paper describes a transcoding algorithm able to transcode a compressed video bitstream into a WMV9 (VC1) compliant bitstream. A Closed-Loop Spatial Domain Transcoding approach, modeled on the Cascaded Pixel Domain Transcoder (CPDT) is presented here. It incorporates reusing of information obtained from the input bitstream. To enhance the performance of the transcoder, an approach for pipelining the encoder/decoder processes in the transcoder is proposed here. These modifications can be easily adapted to all the transcoders producing WMV9 as output, the input for whom may include video streams of type MPEG-2, MPEG-4 or H.264. As a proof of concept, the suggested approach has been applied to the case of MPEG-2 to VC1 transcoding. Extensive analysis has been performed and the ultimate gain in transcoding speed achieved for the presented approach compared with MPEG-2 to VC1 CPDT, is in the range of 3 to 7 times faster than CPDT.

Transform domain based image / video privacy protection.

This paper presents a novel method for protecting privacy sensitive regions inside a digital frame. The purpose is achieved by deteriorating the visual quality of privacy sensitive region by adding probability model based random noise to nonzero quantized transform coefficients of the region. The probabilistic model based noise is generated based on the information from neighboring macroblocks and added only to selective non zero AC transform coefficients to have minimal impact on bit rate. Moreover, the parameters of the probability model are derived from the neighboring blocks inside the frame such that the noise follows characteristics of the frame content. For the purpose of implementation, we used H.264/AVC video coding standard for videos and JPEG image compression standard for images. The probabilistic model based noise is generated using a secret key, which can be shared with the authorized decoder such that the obfuscated region can be completely recovered. In order to limit drifting of obfuscation effect outside the targeted regions, Inter and Intra prediction blocks inside H.264/AVC encoder were modified. Overall, we achieve good obfuscation of selected regions with minimal impact on coding efficiency with the capability to achieve complete reconstruction at the authorized decoder.

Retro-fitting VP8 in existing hardware IPs: Approach and considerations

The document, which includes three blank pages, was not presented at the conference and therefore was not made available for publication as part of the conference proceedings.

Differential illumination of regions of interest for power efficient video playback

This paper describes a method to optimize the power needed to display a video by better illuminating the regions of interest compared to the rest of the video. This method identifies the regions of interest by utilizing parameters from the digital video codecs. It also employs temporal and spatial filters to improve perceptual quality of the video. For our experiment we used MPEG-2 [1] encoded video bitstream and used its motion vectors for identifying the regions of interest, and the results show that the regions of interest are better highlighted in comparison to uniformly scaled illumination for similar power savings. In addition, the method has very low complexity of 0.5 MIPS and low memory footprint of 3 KiloBytes only, so it does not add substantial overhead to the computational complexity of the system as well.

Cache-based motion estimation architecture for real-time HDTV Encoding with H.264/AVC

This paper describes an innovative, pipelined, cache-based architecture for a motion estimation coprocessor based on a predictive/recursive algorithm whose computational complexity is low and independent from the search window. The algorithm and the associated architecture yields itself very well to low-power, low-cost video capture devices with low processing capabilities, such as mobile phones, PDAs, or handhelds. The synergy between architecture and algorithmic features allows a high quality output, low memory to cache bandwidth requirements, and a search window independent implementation for H.264/AVC real time video encoding of up to high definition video (HDTV).