Hung-Ju Lee

Scalable rate control for MPEG-4 video

This paper presents a scalable rate control (SRC) scheme based on a more accurate second-order rate-distortion model. A sliding-window method for data selection is used to mitigate the impact of a scene change. The data points for updating a model are adaptively selected such that the statistical behavior is improved. For video object (VO) shape coding, we use an adaptive threshold method to remove shape-coding artifacts for MPEG-4 applications. A dynamic bit allocation among VOs is implemented according to the coding complexities for each VO. SRC achieves more accurate bit allocation with low latency and limited buffer size. In a single framework, SRC offers multiple layers of controls for objects, frames, and macroblocks (MBs). At MB level, SRC provides finer bit rate and buffer control. At multiple VO level, SRC offers superior VO presentation for multimedia applications. The proposed SRC scheme has been adopted as part of the International Standard of the emerging ISO MPEG-4 standard.

On end-to-end architecture for transporting MPEG-4 video over the Internet

With the success of the Internet and flexibility of MPEG-4, transporting MPEG-4 video over the Internet is expected to be an important component of many multimedia applications in the near future. Video applications typically have delay and loss requirements, which cannot be adequately supported by the current Internet. Thus, it is a challenging problem to design an efficient MPEG-4 video delivery system that can maximize the perceptual quality while achieving high resource utilization. This paper addresses this problem by presenting an end-to-end architecture for transporting MPEG-4 video over the Internet. We present a framework for transporting MPEG-4 video, which includes source rate adaptation, packetization, feedback control, and error control. The main contributions of this paper are: (1) a feedback control algorithm based on the Real Time Protocol (RTP) and the Real Time Control Protocol (RTCP); (2) an adaptive source-encoding algorithm for MPEG-4 video which is able to adjust the output rate of MPEG-4 video to the desired rate; and (3) an efficient and robust packetization algorithm for MPEG video bit-streams at the sync layer for Internet transport. Simulation results show that our end-to-end transport architecture achieves good perceptual picture quality for MPEG-4 video under low bit-rate and varying network conditions and efficiently utilizes network resources.

Scalable wavelet coding for synthetic/natural hybrid images

This paper describes the texture representation scheme adopted for MPEG-4 synthetic/natural hybrid coding (SNHC) of texture maps and images. The scheme is based on the concept of multiscale zerotree wavelet entropy (MZTE) coding technique, which provides many levels of scalability layers in terms of either spatial resolutions or picture quality, MZTE, with three different modes (single-Q, multi-Q, and bilevel), provides much improved compression efficiency and fine-gradual scalabilities, which are ideal for hybrid coding of texture maps and natural images. The MZTE scheme is adopted as the baseline technique for the visual texture coding profile in both the MPEG-4 video group and SNHC group. The test results are presented in comparison with those coded by the baseline JPEG scheme for different types of input images, MZTE was also rated as one of the top five schemes in terms of compression efficiency in the JPEG2000 November 1997 evaluation, among 27 submitted proposals.

Scalable rate control for very low bit rate (VLBR) video

This paper presents a scalable rate control scheme (SRC) based on three new concepts: (1) a more accurate rate distortion model, (2) a sliding window method, and (3) an adaptive selection criterion of data points. The SRC scheme achieves a more accurate target bit allocation under the constraints of low latency and limited buffer size. In addition to the picture-level rate control, the SRC scheme is also applicable to the macroblock-level rate control for finer bit allocation and buffer control, and multiple video objects (VOs) rate control for better video object presentation in different applications. The proposed SRC scheme has been adopted in verification model (VM) 5.0 and VM 8.0 of the emerging ISO MPEG-Q standard.

MPEG-4 video transport over the Internet: a summary

With the success of the Internet and flexibility of MPEG-4, transporting MPEG-4 video over the Internet is expected to be an important component of many multimedia applications in the near future. Video applications typically have delay and loss requirements, which cannot be adequately supported by the current Internet. Thus, it is a challenging problem to design an efficient MPEG-4 video delivery system that can maximize the perceptual quality while achieving high resource utilization. This paper addresses this problem by presenting an end-to-end architecture for transporting MPEG-4 video over the Internet. The proposed MPEG-4 video transport architecture ties together a range of technologies from both signal processing and networking areas. The paper provides important experience and insights on how to harness the power of these technologies in designing protocols and mechanisms for MPEG-4 video transport over the Internet.

Rate-distortion based optimization for zerotree entropy wavelet coding

We present a rate-distortion (R-D) based bit allocation scheme for MPEG-4 zerotree entropy based wavelet coding, specifically, the multiscale zerotree entropy coding mode (MQ) of the MPEG-4 visual texture coding tool. With an iterative quadratic R-D model, our algorithm achieves accurate target bit rate and better image quality with fast convergence.

An end-to-end architecture for MPEG-4 video streaming over the Internet

It is a challenging problem to design an efficient MPEG-4 video delivery system that can machine the perceptual quality while achieving high resource utilization. This paper addresses this problem by presenting an architecture of transporting MPEG-4 video over the Internet, which includes an end-to-end feedback control algorithm and a source encoding rate control algorithm. Our feedback control algorithm is capable of estimating the available bandwidth in the network based on the feedback information from the receiver, while our source encoding rate control algorithm is able to adjust the encoding rate of MPEG-4 video to the desired rate. Simulation results demonstrate that our architecture achieves good perceptual picture quality under low bit-rate and varying network conditions while efficiently utilizing network resources.

Multi-scale zerotree entropy coding

This paper describes the visual texture compression scheme adopted for MPEG-4 international standard. The scheme is based on the concept of multiscale zerotree wavelet entropy coding (MZTE) technique that provides different levels of scalability layer in terms of either spatial resolutions or picture quality. MZTE provides much improved compression efficiency and fine-gradual scalabilities. The MZTE scheme is adopted as the baseline technique for the visual texture coding profile in both MPEG4 video group and SNHC group.

Demonstration of the MPEG-2, MPEG-4 and H.263 video coding standards

In this demonstration session, we will demonstrate several examples of the state-of-the-art video compression standards MPEG-2, MPEG-4 and H.263. These demonstrations captured some of the recent work developed in the Digital Video Communications group at Sarnoff. For the MPEG-2 demonstration, the compression process uses standards compliant syntax with Sarnoffs proprietary algorithms to select the encoding parameters. For the MPEG-4 demonstration, we show the encoding results of the Verification Model including Sarnoffs contribution in scalable rate control and texture coding mode. In addition, we show the encoding results of a video streaming technology using H.263 and Sarnoffs proprietary technologies.