Patent ID: 6516002
Filing Date: 2003-02-04
Classification: H04B,H04J,H04N

Abstract:
A multiplexer for multiplexing a plurality of MPEG-2 bit streams onto a transmission medium, each bit stream containing a plurality of varying-length pictures representing video images, each picture containing timing information specifying at least a decoding time for the picture, and each bit stream being provided via the transmission medium to a decoder, the multiplexer comprising:a receiver for receiving the bit streams; a transmitter for providing the bit streams to the transmission medium; and for each bit stream, a bit stream analyzer for: detecting the timing information in a picture being received by the receiver; and detecting the size of the picture being received by the receiver; and a transmission rate controller which is coupled between the receiver and the transmitter, the transmission rate controller comprising a queue into which the bit stream is written from the receiver and from which portions of the bit stream are read to the transmitter and a queue fullness detector, the transmission rate controller providing the detected timing information and the detected picture size to a model of the bit stream's decoder and using the model to determine a portion of the received bit stream to be provided to the transmitter, the portion being sized to prevent overflow of the decoder and to ensure that the picture will be received in the decoder prior to the decoding time, and further responding to the queue fullness detector such that the portion to be transmitted is sized so that the queue does not overflow.