Rate adaptation transcoding for precoded video streams
Rate adaptation transcoding for precoded video streams
复制标题
预编码视频流的速率自适应转码
DOI：
10.1145/641007.641033
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
N. Georganas
中科院分区：
文献类型：
--
作者：
Zhijun Lei;N. Georganas
为了在异构网络上传输预编码的数字视频，必须采用将预编码的视频流转换成具有不同比特率和质量的流的转码技术。指定的问题被称为速率整形或速率适配。在这项工作中，我们提出了一种新的码率控制方案的H.263+为基础的视频转码。提出的码率控制方案包括帧层比特分配和宏块层码率控制。在帧层，利用来自输入视频流的场景上下文统计来检测场景变化并确定帧类型。根据帧的能量和帧类型将比特预算分配给帧。在宏块层，采用一种新的线性码率量化模型来选择宏块的量化参数。实现和实验结果表明，该算法能够提供准确的比特分配，并能有效缓解场景变化后的视觉质量下降。该速率自适应方案可用于为异构网络上的预编码视频的传输提供灵活的视频比特率自适应。
In order to transmit pre-encoded digital video over heterogeneous networks, it is necessary to employ transcoding techniques that convert pre-encoded video streams into streams having different bit rates and quality. The specified problem is referred to as rate shaping or rate adaptation. In this work, we propose a new rate control scheme for H.263+ based video transcoding. The proposed rate control scheme is comprised of Frame-Layer bit allocation and Macroblock-Layer rate control. At the frame layer, scene context statistics from the incoming video stream are utilized to detect scene changes and determine frame type. The bit budget is allocated to frames according to their energy and frame types. At the macroblock layer, a novel linear Rate-Quantization model is used for selecting quantization parameters for macroblocks. Implementation and experimental results show that the proposed algorithm can provide accurate bit allocation, and can effectively alleviate visual quality degradation after scene changes. This rate adaptation scheme can be used to provide flexible video bit rate adaptation for transmission of pre-encoded video over heterogeneous networks.