| 摘要 |
<p>According to one aspect of the present invention there is provided a method of changing the throughput of data in a digital data transmission system, comprising, monitoring the rate of data input to an encoder buffer to determine the decoder buffer requirements downstream; and controlling the encoder buffer in response to the monitoring step such that a change in the rate of data output from the encoder is lagged by a predetermined time period from any change in rate of data input to the encoder buffer. This predictive technique achieves the requirement of instantly changing bitrate in a seamless manner. A seamless bitrate change implies that there is no break in the decoding of the bitstream at the receiver, and also no abnormal artefacts at the receiver. Therefore to change bitrate seamlessly the receiver buffer should not be overflowed or underflowed, and the time stamp offset in the bitstream (the rate buffer delay) should remain constant so that the receiver need not gain or skip frames.</p> |
