Abstract

This paper proposes a new rate control scheme to increase the coding efficiency for MPEG systems. Instead of using a static group of picture (GOP) structure, we present an adaptive GOP structure that uses more P-and B-frame coding, while the temporal correlation among the video frames maintains high. When there is a scene change, we immediately insert intramode coding to reduce the prediction error. Moreover, an enhanced prediction frame is used to improve the coding quality in the adaptive GOP. This rate control algorithm can both achieve better coding efficiency and solve the scene change problem. Even if the coding bit rate is over the predefined level, this coding scheme does not require re-encoding for real-time systems. Simulations demonstrate that our proposed algorithm can achieve better quality than TM5, and satisfactory reliability for detecting scene changes.

Highlights

  • The video coding systems have been widely applied to digital TV, video conferencing, multimedia systems, and so forth, primarily, in order to reduce the bit rates [1, 2, 3]

  • The fundamental buffer control strategy adjusts the quantizer scale according to the level of buffer utilization [4, 5, 6]

  • In MPEG coding systems, the fixed group of picture (GOP) structure is IBBPBBPBBPBBI, where the I-frame is the basic reference for P- or B-frame coding

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Summary

INTRODUCTION

The video coding systems have been widely applied to digital TV, video conferencing, multimedia systems, and so forth, primarily, in order to reduce the bit rates [1, 2, 3]. To regulate the fluctuation of the coding rate, we need to allocate the compressed bit of each frame by choosing a suitable quantization parameter for each macroblock. The selection of quantization scale, coding mode, and picture type will decide the coding bit rate, and affect the coding quality. If the coding result is not satisfactory, re-encoding procedures are required in these approaches. Because this re-encoding process will increase the computational time, it is not desirable for real-time applications. Our method can decide the coding parameters at once and avoid the need for re-encoding procedures even if the coding bit rate is over the predefined maximum level or a scene change is detected.

AN ADAPTIVE CODING CONTROL ALGORITHM
A new adaptive GOP structure
For BGOP structure
For the AGOP
EXPERIMENTAL SIMULATIONS
Methods
Findings
CONCLUSIONS
Full Text
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