本规程定义了符合SMPTE 328M提供的框架的MPEG-2视频基本流中垂直辅助（V-ANC）数据包的映射。本规程的目的是提供一种通过SMPTE 328M提供的8位接口映射V-ANC数据包的方法，并为数据编码提供指导，以防止错误创建MPEG-2视频基本流起始标记位序列。尽管这种做法涉及位串行接口，但该描述同样适用于等效的并行接口。

This practice defines the mapping of vertical ancillary (V-ANC) data packets within MPEG-2 video elementary streams conforming to the framework provided by SMPTE 328M. The purpose of this practice is to provide a method of mapping V-ANC data packets through the 8-bit interface provided by SMPTE 328M and to provide guidance for data coding to prevent the false creation of MPEG-2 video elementary stream start marker bit sequences. Although this practice refers to bit-serial interfaces, the description can be equally applied to the equivalent parallel interfaces.