. Optimum bit allocation and accurate rate control for video coding via ρ-domain source modeling
. Optimum bit allocation and accurate rate control for video coding via ρ-domain source modeling
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DOI：
10.1109/tcsvt.2002.804883
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发表时间：
2002-10
期刊：
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通讯作者：
Zhihai He;S. Mitra
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文献类型：
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作者：
Zhihai He;S. Mitra
我们提出了一个新的速率（R-D）分析框架，其中编码率R和失真d被视为 / spl rho /的函数，这是量化变换系数中零的百分比。以前（参见He，Z。等，Int。Conf。声学，语音和Sig。Proc。，2001），我们观察到，在图像和视频的转换编码中，速率函数R（/Spl Rho/）为大约线性。基于此线性速率模型，为所有标准视频编码系统（例如MPEG-2，H.263和MPEG-4）提出了一种简单而统一的速率控制算法。我们进一步开发了 / spl rho /域中的失真模型和最佳的位分配方案。此位分配方案应用于MPEG-4视频编码，以在不同的视频对象之间分配可用位。然后，我们的 /spl rho / - 域速率控制算法实现了每个对象的位目标。当与大小写分类方案结合使用时，上述位分配和费率控制方案也可以应用于其他视频编码系统，例如H.263，在Macroblock级别。我们广泛的实验结果表明，所提出的算法可以非常准确地控制编码器比特率，并显着提高了视频质量（最高1.5 dB）。
We present a new framework for rate-distortion (R-D) analysis, where the coding rate R and distortion D are considered as functions of /spl rho/ which is the percentage of zeros among the quantized transform coefficients. Previously (see He, Z. et al., Int. Conf. Acoustics, Speech and Sig. Proc., 2001), we observed that, in transform coding of images and videos, the rate function R(/spl rho/) is approximately linear. Based on this linear rate model, a simple and unified rate control algorithm was proposed for all standard video coding systems, such as MPEG-2, H.263, and MPEG-4. We further develop a distortion model and an optimum bit allocation scheme in the /spl rho/ domain. This bit allocation scheme is applied to MPEG-4 video coding to allocate the available bits among different video objects. The bits target of each object is then achieved by our /spl rho/-domain rate control algorithm. When coupled with a macroblock classification scheme, the above bit allocation and rate control scheme can also be applied to other video coding systems, such as H.263, at the macroblock level. Our extensive experimental results show that the proposed algorithm controls the encoder bit rate very accurately and improves the video quality significantly (by up to 1.5 dB).