This paper proposes changing of picture orientation on a picture-by-picture basis, without requiring the encoding of an Instantaneous Decoder Refresh (IDR) picture. It can be implemented by small modifications to H.264/MPEG-4 AVC and the design of the upcoming High Efficiency Video Coding (HEVC) standard, or most other video coding technologies employing inter picture prediction. To enable picture orientation changes, a high layer syntax element is needed to indicate the rotation to be applied to the decoded pictures. Modifications to the decoding process are also required to avoid the use of IDR pictures. For some applications with handheld cameras that may be held at different orientations, the proposed modifications allow shifting the rotation function to the decoding end, reducing overall system complexity. Additionally, selection by the encoder of the coded picture orientation may result in better coding efficiency. In this respect, an algorithm for selecting the coded picture orientation limited to intra coding is also described, and experimental results show coding efficiency improvements up to 3.4% BD-rate gain.

A scalability extension design is proposed to the upcoming High Efficiency Video Coding (HEVC) standard, to support spatial and SNR scalability. The design attempts to minimize changes needed for the enhancement layer codec from the single layer HEVC codec, re-using existing tools exactly wherever possible. Experimental results are provided for the 2 layer spatial scalability case with 1:2 ratio in each dimension, although the design can be extended to any spatial ratios and to more than 2 layers. Coding gains of up to 24.4% vs. HEVC simulcast coding are shown.

Despite the attention that hierarchical B picture coding has received, little attention has been given to a related technique called hierarchical P picture coding. P picture only coding without reverse prediction is necessary in constrained bit rate applications that require ultra-low delay and/or low complexity, such as videoconferencing. Such systems, however, have been using the traditional IPPP picture coding structure almost exclusively. In this paper, we investigate the use of hierarchical P coding vs. traditional IPPP coding and demonstrate that it has significant advantages which have not yet been well documented or understood. From a pure coding efficiency point of view, we show that for encoders configured to use ultra-low delay and low complexity coding tools, hierarchical P coding achieves an average advantage of 7.86% BD-rate and 0.34 dB BD-SNR.

We propose a highly efficient, look-up table-based, renormalization method that can be used by any binary arithmetic encoder with the follow-on procedure. It replaces the time- consuming branching operations in the renormalization process with table look-ups and some simple bit-wise operations. We show that our new renormalization method outperforms the currently used ones with much less memory requirement than the previously known, table-based quasi-coder.

We introduce a video newsgathering system called mobile broadcast video. The system is designed to use a wireless LAN and low earth orbit satellite technology for increased mobility and wide area coverage. It offers broadcast-quality video by using the MPEG-2 standard for audio/video compression and multiplexing. Our prototype uses off-the-shelf hardware components with all system software developed in-house. We present our implementation, focusing particularly on real-time live video acquisition and fast delivery of the high-rate compressed data over a wireless LAN. We also introduce an effective MPEG-2 transport stream level error concealment scheme that increases subjective played-back audiovisual quality in the case of packet losses. Through experimental results, we demonstrate that an economical, high-quality, real-time solution for mobile video newsgathering and broadcasting is realizable using even wireless 802.11b LANs.

A highly efficient, lookup table-based, renormalization method is proposed, which can be used by any binary arithmetic coder with the follow-on procedure. It replaces the time-consuming branching operations in the renormalization process with table lookups and some simple bit-wise operations. We show that the proposed method is much faster than the one used by the M coder in the CABAC entropy coding scheme of the H.264 video coding standard. Our method requires much less memory than the previously known, table-based quasi-coder.

We present Flavor, a formal language for audio-visual object representation, that has been developed to describe any coded multimedia data in formats such as GIF, JPEG and MPEG. The language comes with a translator for generating C++/Java code from the Flavor description, and the generated code can include bitstream reading, writing and tracing methods. Since Version 5.0, the translator has been enhanced to also support XML. With the enhanced translator, the generated C++/Java code can include a method for producing XML documents that correspond to the bitstreams described by Flavor. The description can also be used to generate a corresponding XML schema. Additionally, a software tool for converting XML representation of multimedia data back into bitstream form is provided.

We propose applying an adaptive context-tree weighting (CTW) method in the H.264 video coders. We first investigate two different ways to incorporating the CTW method into an H.264 coder and compare the coding effectiveness of using the method with that of using the context models specified in the H.264 standard. We then describe a novel approach for automatically adapting the CTW method based on the syntactic element to be coded and the encoding parameters. We show that our CTW-based arithmetic coding method yields similar or better compression results compared with the context-based adaptive arithmetic coding method used in H.264, without having to specify so many context models.

Flavor is a formal language developed for describing compressed bitstream syntax, especially the bitstreams representing multimedia objects. A translator is also available for translating a Flavor description into C++ or Java code. The code includes bitstream parsing and generating operations that can readily be used by software developers with essentially zero additional programming. After briefly describing the latest version of Flavor, we propose an extension - XFlavor - that provides XML features by transforming the traditional bitstream representation of multimedia data into a corresponding XML representation.