System for synchronization by modifying the rate of conversion by difference of rate between first clock and audio clock during a second time period

An apparatus for synchronizing the presentation of a data stream to a first clock having a first frequency, said data stream having a plurality of samples, said apparatus comprising:

• a) a first logic circuit having an input for receiving a data stream, said first logic circuit for performing rate conversion on the data stream at a first rate of conversion for a first period of time;
• b) a digital to analog conversion circuit, coupled to the first logic circuit, for converting the samples into analog waveforms at a second rate of conversion;
• and
• c) a second logic circuit, coupled to a first clock having a first frequency, the digital to analog converter and the first logic circuit, said second logic circuit receiving a first value from the digital to analog converter, said value representing the number of samples played through the conversion circuit at any given time and based on the first value modifying the rate of conversion to provide a modified rate of conversion, wherein said rate of conversion is modified based on a measurement of a difference between a rate for the first clock having a first frequency and a rate of a second clock having a second frequency, wherein said second clock is an audio clock of an audio subsystem.

An apparatus for synchronizing the presentation of a data stream, said data stream having a plurality of samples, said apparatus comprising:

• a) first logic circuit having an input for receiving the data stream, said first logic circuit for performing rate conversion on the data stream at a first rate of conversion for a first period of time;
• b) a data buffer, coupled to the first logic circuit, for storing data values;
• c) a conversion circuit, coupled to the data buffer for converting the samples into analog waveforms at a second rate of conversion;
• and
• d) a second logic circuit, coupled to a first clock having a first frequency and the data buffer, and the first logic circuit, said second logic circuit receiving a first value representing the number of samples stored in the data buffer at any given time and based on the first value modifying the rate of conversion of the first logic circuit to provide a modified rate of conversion to the first logic circuit, wherein said rate of conversion is modified based on a measurement of a difference between a rate for the first clock having a first frequency and a rate of a second clock having a second frequency, wherein said second clock of a second frequency is an audio clock of an audio subsystem.

In a computer system having a digital media source connected with a digital media presentation device, the digital media source and the digital media presentation device each having a first and second clock, a method for synchronizing the presentation of a data stream sent by the digital media source to the digital media presentation device comprising the steps of:

• a) said digital media presentation device receiving the stream of data;
• b) synchronizing the first clocks of the digital media source and the digital media presentation device via a synchronization protocol;
• c) synchronizing the presentation of the data using the second clock of the digital media presentation device to the first clock of the digital media presentation device by performing the following
• i) performing a rate conversion of said data stream for a first period of time, said rate conversion having a first rate of conversion;
• ii) modifying the first rate of conversion to provide a modified rate of conversion, wherein said rate of conversion is modified based on a measurement of a difference between a rate for the first clock having a first frequency and a rate of the second clock having a second frequency, wherein said second clock of a second frequency is an audio clock of an audio subsystem in the workstation;
• and
• iii) performing a rate conversion on said data stream with the modified rate of conversion for a second period of time.

An apparatus for synchronizing the presentation of a data stream, said data stream having a plurality of samples, said apparatus comprising:

• a) first logic circuit having an input for receiving a data stream, said first logic circuit for performing rate conversion on the data stream at a first rate of conversion for a first period of time;
• b) a conversion means, coupled to the first logic means for converting the samples into analog waveforms at a second rate of conversion;
• and
• c) a second logic means coupled to a first clock having a first frequency and the first logic means, said second logic means having an input for receiving a first value, said first value representing the number of samples played through the conversion means at any given time and based on the first value modifying the rate of conversion to provide a modified rate of conversion, wherein said rate of conversion is modified based on a measurement of a difference between a rate for the first clock having a first frequency and a rate of a second clock having a second frequency, wherein said second clock is an audio clock of an audio subsystem.