Method of video buffer verification

A Motion Picture Experts Group (MPEG) video transmission system comprising:

• a MPEG encoder for encoding input data as a compressed data bitstream, for generating a parameter from an instantaneous encoder delay of data passing through an encoder buffer for insertion into the compressed data bitstream, and for providing variable bit rates for outputting the compressed data bitstream, the parameter being computed as a constant minus the instantaneous encoder delay of data passing through the encoder buffer and being substantially equal to a decoder delay;
• the encoder buffer having the instantaneous encoder delay of data passing therethrough for transmitting the compressed data bitstream from the MPEG encoder over a variable rate transmission channel operatively connected to the encoder buffer;
• a decoder buffer operatively connected to the encoder buffer by the variable rate transmission channel for receiving the compressed data bitstream, the decoder having the decoder delay wherein a sum of the encoder delay and the decoder delay is constant;
• and
• a MPEG decoder for receiving the compressed data bitstream from the decoder buffer over the variable rate transmission channel, for extracting the parameter therefrom associated with the encoder delay of data passing through the encoder, for decoding the compressed data bitstream, for using the parameter to periodically obtain the decoder delay, and for using at least the decoder delay to synchronize the encoder buffer and decoder buffer;
• wherein the decoder delay is determined based on an instantaneous arrival time at said encoder buffer and an instantaneous removal time from said encoder buffer of said data encoded within said compressed data bitstream to arrive at said encoder buffer and to be removed from said encoder buffer.

A method for transmitting data at variable rates comprising the steps of:

• determining an instantaneous encoder buffer delay of data passing through an encoder buffer, said instantaneous encoder buffer delay being substantially equal to a difference between the time of removal of said data from said encoder buffer and the time of arrival of said data to said encoder buffer;
• generating a synchronization control signal from the instantaneous encoder buffer delay of data passing through the encoder buffer using the encoder, the synchronization control signal including a decoder buffer delay determined as a constant minus the value of the instantaneous encoder buffer delay;
• encoding input data using the encoder to provide a compressed data bitstream, including the synchronization control signal;
• transmitting the compressed data bitstream, including the synchronization control signal to a decoder buffer over a variable rate transmission channel operatively connected to the encoder buffer and the decoder buffer using a variable rate;
• receiving, by the decoder buffer, the compressed data bitstream, including the synchronization control signal;
• removing and decoding the compressed data bitstream, including the decoder buffer delay from the synchronization control signal, from the decoder buffer;
• and
• synchronizing the encoder and decoder buffers using at least the decoder buffer delay, whereby the sum of the encoder buffer delay and the decoder buffer delay is a constant, wherein said decoder buffer delay is determined based on an instantaneous arrival time at said encoder buffer and an instantaneous removal time from said encoder buffer of said data encoded within said compressed data bitstream to arrive at said encoder buffer and to be removed from said encoder buffer.

A method for transmitting data at variable rates comprising the steps of:

• encoding input data using an encoder to a compressed data bitstream;
• periodically determining an instantaneous delay time for a specified portion of the compressed data bitstream to propagate through an encoder buffer;
• inserting a buffer synchronization parameter into the compressed data bitstream, wherein the buffer synchronization parameter is determined as a constant minus the instantaneous delay time of the specified portion to propagate through the encoder buffer;
• transmitting the compressed data bitstream, including the buffer synchronization parameter, from the encoder buffer at a variable rate over a variable rate transmission channel operatively connected to the encoder buffer which is synchronized with a second buffer using the buffer synchronization parameter;
• extracting, at a decoder, the synchronization parameter;
• and
• synchronizing the encoder buffer with the second buffer using the buffer synchronization parameter by removing encoded data from said second buffer at a rate equal to the constant minus the instantaneous delay time for the specified portion to propagate through the encoder buffer, said rate being substantially equal to a delay of the second buffer, wherein said rate is determined based on an instantaneous arrival time at said encoder buffer and an instantaneous removal time from said encoder buffer of said specified portion of said compressed data bitstream to arrive at said encoder buffer and to be removed from said encoder buffer.