Avhelper and the av server operate realtime streaming protocol ( rtsp ) to exchange the control information needed for av transmission . similar to the function provided by cd players or vcrs , rtsp provides mechanisms for operate commands such as play , fast forward , fast reverse and record Avhelper程序及av服务器运行实时流控制协议（ rtsp ） ，以交换av传输所需的控制信息。与cd播放机或vcr所提供的功能相似， rtsp提供了操纵播放、快进、快倒、暂停及录制等命令的方法。
The unicast service module provides the customer with service based on point - to - point connectivity and the station service module , with service based on broadcast . unicast service is in turn divided into on - demand unicast and broadcast unicast , depending on the extent of participation by the user 而unicast服务又可以按用户的参与程度分为两种，一是on - demandunicast ，这种方式下，用户建立和发布服务器的点对点连接，可以控制播放的过程，包括开始、暂停、快进等。
A new kind of robust h control tactic based on ip controller for dynamical and rapid high - precision - feed in a single axis is proposed in this paper , and the problem of h2 / h is also introduced , in which a constraint condition on y is deduced . the background of the paper is " theory of dynamic precision synchronization traverse and research of realization methods for linear servo dual position loops system ( no . 50075057 ) " , which is supported by national natural science foundation of china 本文以国家自然科学基金资助项目《直线伺服双位置环动态精密同步进给理论和实现方法研究( n _ o . 50075057 ) 》为背景，基于h _控制理论，提出了直线伺服单位置环的高精度快进给的鲁棒h _控制方案，并进一步研究了h2 h混合控制问题，给出了一个约束的条件。
