Clock correction in a video data decoder using video synchronization signals

A method for alignment of a decoding clock in a video data decoder with an encoding clock, comprising the steps of:

• receiving a video data stream with encoded video data at the video data decoder, the video data stream including an encoder clock signal representing a frequency of the encoding clock with which the video data is encoded;
• providing the decoding clock at the video data decoder, the decoding clock having a frequency that is substantially equal to the encoding clock frequency;
• decoding the video data from the video data stream at the video data decoder in response to the decoding clock;
• producing composite video data from the decoded video data at the video data decoder;
• and
• slewing the decoding clock frequency to reduce a frequency difference between the encoding clock and the decoding clock, the slewing being performed in response to the encoder clock signal and to video synchronization signals in the composite video data.

A method for alignment of a decoding clock in a video data decoder with an encoding clock, comprising the steps of:

• receiving a video data steam with encoded video data at the video data decoder, the video data stream including an encoder clock signal representing a frequency of the encoding clock with which the video data is encoded;
• providing the decoding clock at the video data decoder, the decoding clock having a clock frequency that is substantially equal to the encoding clock frequency;
• decoding the video data from the video data stream at the video data decoder in response to the decoding clock;
• producing composite video data from the decoded video data at the video data decoder;
• and
• changing the frequency of the decoding clock to reduce a frequency difference between the encoding clock and the decoding clock, the changing being performed in response to the encoder clock signal and to video synchronization signals in the composite video data.

A combination for adjustment of a decoding clock in a video data decoder, the decoding clock having a decoding clock frequency that is substantially equal to an encoding clock frequency, the combination comprising:

• means for receiving a video data stream with encoded video data, the video data stream including an encoder clock signal representing the frequency of the encoding clock with which the video data is encoded;
• a decoding clock circuit for providing the decoding clock;
• a video data decoder coupled to the decoding clock circuit and to the means for receiving for decoding the video data from the video data stream in response to the decoding clock;
• a composite video generator coupled to the video data decoder for generating composite video data from the decoded video data in response to the decoding clock;
• and
• a clock rate alignment circuit coupled to the composite video generator and to the decoding clock circuit for adjusting the decoding clock to match the decoding clock with the encoding clock in response to the encoder clock signal and to video synchronization signals in the composite video data.

A combination for alignment of a decoding clock with an encoding clock, the combination comprising:

• means for receiving a video data stream with encoded video data, the video data stream including an encoder clock signal representing a frequency of the encoding clock with which the video data is encoded;
• a decoding clock circuit for providing the decoding clock having a frequency that is substantially equal to the encoding clock frequency;
• a video data decoder coupled to the means for receiving and to the decoding clock circuit for providing the video data in response to the video data stream and the decoding clock;
• a composite video generator coupled to the decoding clock circuit and the video data decoder for generating composite video data from the provided video data in response to the decoding clock;
• and
• a clock rate alignment circuit coupled to the composite video generator, to the means for receiving, and to the decoding clock circuit for slewing the frequency of the decoding clock in response to the encoder clock signal and to video synchronization signals in the composite video data.

A combination for alignment of a decoding clock with an encoding clock, the combination comprising:

• means for receiving a video data stream with encoded video data, the video data stream including an encoder clock signal representing a frequency of the encoding clock with which the video data is encoded;
• a decoding clock circuit for providing the decoding clock having a frequency that is substantially equal to the encoding clock frequency;
• a video data decoder coupled to the means for receiving and to the decoding clock circuit for providing the video data in response to the video data stream and the decoding clock;
• a composite video generator coupled to the decoding clock circuit and the video data decoder for generating composite video data from the provided video data in response to the decoding clock;
• and
• a clock rate alignment circuit coupled to the composite video generator, to the means for receiving, and to the decoding clock circuit for changing the frequency of the decoding clock in response to the encoder clock signal and to video synchronization signals in the composite video data.