Other Free Encyclopedias » Online Encyclopedia » Encyclopedia - Featured Articles » Contributed Topics from A-E

Active Buffer Management for Provision of VCR Functionalities

segment play middle actions

Definition: Active buffer management is used to adjust the contents of the buffer after execution of VCR functions in VoD systems.

The problem of providing VCR functions with the traditional buffering schemes is that the effects of VCR actions in the same direction are cumulative. When consecutive VCR actions in the same direction are performed, the play point will ultimately move to a boundary of the buffer. Thus, the active buffer management (ABM) scheme was developed to use a buffer manager to adjust the contents of the buffer after the VCR functions such that the relative position of the play point can stay in the middle of the buffer. Figure 1 shows the basic operational principle of ABM in a staggered VoD system with no VCR actions. Assuming the buffer can hold 3 segments. At some point, the buffer downloads segments z, z+1, z+2 and the play point is in segment z+1. If there is no VCR action, after a period of time, the play point will be at the start of segment z+2. At this moment, in order to keep the play point in the middle, the client will download segment z+3 and segment z will be discarded.

For the scenario with an interactive function, it is assumed that the buffer now holds segment z , z 1 and z 2. If a FF action as illustrated in Figure 2 is issued and the play point moves to the end of segment z 2, the buffer manager will select segment z 3 and   z 4 to download. The play point will thus be moved back to the middle segment after one segment time. This is segment z 3 in this case.

Acuff,Roy(Clayton) - DISCOGRAPHY, WRITINGS, BIBLIOGRAPHY [next] [back] Act of Violence

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or