PCR timing control in variable bit rate (VBR) transport streams

摘要

In a method for transmitting data in packets in a transport stream the temporal relationship is stored in memory with each of the packets in that a timestamp is attached to each packet that reflects the exact arrival time of a data element of the packet. To accomplish this, a firmware counter called the Receive Timing Register (RTR) is clocked by a local oscillator to generate a Receive Timing Register value at the time the PCR reference bit arrives to create a timestamp that is associated with each packet. The oscillator and firmware register are located on the card that receives the stream. Alternatively stuffing is applied to each packet to control the transmission rate by the length of the sequentially transmitted packets. This can be done at alternating faster and slower rates or can be applied between PCR packets.