Streaming media technology includes a back buffer configured to begin at a stream frame most recently played by the streaming media player. The back buffer continues, for each played frame of the stream, for a length determined by a nominal fill and an offset. In some embodiments, the offset is determined in runtime. In some embodiments the runtime-determined offset is determined by the position of a keyframe in the vicinity of the nominal fill. The keyframe in the vicinity of the nominal fill can be a keyframe next earlier, next later, or nearest in the stream to the location of the nominal fill.
In general, in one aspect, streams associated with a playlist are received from a server. The playlist includes an ordering of streams that are queued for client-side playback from the server according to the ordering. Information associated with the receipt and playback of at least one of the streams is accessed. The client-side application requests to alter the streams of the playlist in response to the accessed information. The request identifies a desired playlist alteration and includes information that controls the playlist alteration. The streams of the playlist are displayed according to a playlist alteration made in response to the request.