Scalable video coding is attractive due to the capability of reconstructing lower resolution or lower quality signals from partial bit streams. This allows for simple solutions in adaptation to network and terminal capabilities. Different modalities of scalability are specified by video coding standards like MPEG-2 and MPEG-4. This paper gives a short overview over these techniques and analyzes in more detail the encoder/decoder drift problem, which is the major reason why scalable coding has been significantly less efficient than single-layer coding in most of these implementations. Only recently, new scalable video coding technology has evolved, which seems to close the gap of compression performance compared to state of the art single-layer video coding. New methods of efficient enhancement layer prediction were developed to improve traditional (motion-compensated hybrid) scalable coders, providing more flexible compromises on the drift problem. As a new technology trend, motion-compensated spatiotemporal wavelet coding has matured which entirely discards the drift and allows most flexible combinations of spatial, temporal, and signal-to-noise ratio (SNR) scalability with fine granularity over a broad range of data rates.

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Multimedia Communication Technology

Advances in Scalable Video Coding

Variable block size transforms for hybrid video coding

Scalability at the bitstream level is an important feature for encoded video that is to be transmitted and stored with a variety of target rates or to be replayed on devices with different capabilities and resolutions. This is attractive for digital cinema applications, where the same encoded source representation could seamlessly be used for purposes of archival and various distribution channels. Conventional high-performance video compression schemes are based on the method of motion-compensated prediction, using a recursive loop in the prediction process. Due to this recursion and the inherent drift in cases of deviation between encoder and decoder states, scalability is difficult to realize and typically effects a penalty in compression performance for prediction-based coders. The method of interframe wavelet coding overcomes this limitation by replacing the prediction along the time axis by a wavelet filter, which can nevertheless be operated in combination with motion compensation. Recent advances in motion-compensated temporal filtering (MCTF) have proven that combination with arbitrary motion compensation methods is possible. Compression performance is achieved that is comparable with state of the art single-layer coders targeting only for one rate. The paper provides an explanation of MCTF methods and the resulting 3D wavelet representation, and shows results obtained in the context of encoding digital cinema (DC) materials.

/pdf/interframe-wavelet-coding-motion-picture-representation-for-f8p9q1qen6.pdf

Interframe wavelet coding—motion picture representation for universal scalability

In this letter, we provide a theoretical analysis of optimal predictive transform coding based on the Gaussian Markov random field (GMRF) model. It is shown that the eigen-analysis of the precision matrix of the GMRF model is optimal in decorrelating the signal. The resulting graph transform degenerates to the well-known 2-D discrete cosine transform (DCT) for a particular 2-D first order GMRF, although it is not a unique optimal solution. Furthermore, we present an optimal scheme to perform predictive transform coding based on conditional probabilities of a GMRF model. Such an analysis can be applied to both motion prediction and intra-frame predictive coding, and may lead to improvements in coding efficiency in the future.

Additional excerpts

https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/OptimalityOfDCT.pdf

Analyzing the Optimality of Predictive Transform Coding Using Graph-Based Models

The accurate prediction of quality from an end-user perspective has received increased attention with the growing demand for compression and communication of digital image and video services over wired and wireless networks. The existing quality assessment methods and metrics have a vast reach from computational and memory efficient numerical methods to highly complex models incorporating aspects of the human visual system. It is hence crucial to classify these methods in order to find the favorable approach for an intended application. In this paper a survey and classification of contemporary image and video quality metrics is therefore presented along with the favorable quality assessment methodologies. Emphasis is given to those metrics that can be related to the quality as perceived by the end-user. As such, these perceptual-based image and video quality metrics may build a bridge between the assessment of quality as experienced by the end-user and the quality of service parameters that are usually deployed to quantify service integrity.

/pdf/perceptual-based-quality-metrics-for-image-and-video-4e1uzmhlt2.pdf

Multimedia Communication Technology

Citations

Advances in Scalable Video Coding

Variable block size transforms for hybrid video coding

Interframe wavelet coding—motion picture representation for universal scalability

Analyzing the Optimality of Predictive Transform Coding Using Graph-Based Models

Perceptual-based Quality Metrics for Image and Video Services: A Survey

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