A server system includes one or more processors, a clock, and memory. The memory stores one or more programs configured for execution by the one or more processors. The server system receives a program manifest (e.g., a playlist) for a video from a content delivery network. The video includes a plurality of video segments. The server system parses the program manifest to identify a timeline for the video, then determines the current playback position for the video and a corresponding initial timestamp according to the clock. The server system periodically updates the current playback position for the video according to the clock and the initial timestamp. Over a span of time the server system receives requests from a plurality of client devices to view the video. For each request from a respective client device, the server system sends the current playback position to the respective client device.