Method and apparatus for regenerating a clock for auxiliary data transmitted over a serial link with video data

A transmitter configured to be coupled to a serial link having at least one video channel and at least one video clock channel, said transmitter including:

• at least one input coupled to receive video data and at least one input coupled to receive audio data;
• at least two outputs configured to be coupled to the link, including a clock output configured to be coupled to the video clock channel;
• and
• circuitry, coupled between the outputs and each said input, and configured to generate encoded video data and encoded audio data by encoding the video data and audio data, to assert code words indicative of the encoded video data to at least one of the outputs in response to a pixel clock during active video periods, to assert packets including encoded auxiliary data to at least one of the outputs during data islands, and to assert the pixel clock to the clock output,
• wherein each of the data islands is a time interval that neither coincides with nor overlaps any of the active video periods, the encoded auxiliary data include the encoded audio data, the circuitry is configured to include time code data in at least some of the packets, the time code data are indicative of time stamps, and the time code data together with the pixel clock are indicative of an audio clock for the audio data.

A receiver configured to be coupled to a serial link having at least one video channel and at least one video clock channel, said receiver including:

• at least two inputs configured to be coupled to the link, including a clock input configured to be coupled to the video clock channel;
• at least one video output for asserting video data recovered from the link and at least one audio output for asserting audio data recovered from the link;
• and
• circuitry, coupled between the inputs and each said output, and configured to receive a pixel clock from the clock input, to generate recovered video data including by decoding encoded video data received at at least one of the inputs during active video periods in response to the pixel clock, to assert the recovered video data to the at least one video output, to generate decoded data including by decoding code words of packets of encoded auxiliary data received at at least one of the inputs during data islands in response to the pixel clock, to generate at least one stream of audio data from the decoded data, and to assert each said stream of audio data to the at least one audio output, wherein each of the data islands is a time interval that neither coincides with nor overlaps any of the active video periods,
• wherein at least some of the decoded data are time code data indicative of time stamps, and the time code data together with the pixel clock are indicative of an audio clock for the audio data.

A method for recovering an audio clock from data and a video clock that have been transmitted over a serial link having video channels and a video clock channel, wherein the data include encoded video data received on the video channels during active video periods, and packets including encoded auxiliary data received on the video channels during data islands, wherein each of the data islands is a time interval that neither coincides with nor overlaps any of the active video periods, and the encoded auxiliary data include encoded audio data, said method including the steps of:

• recovering time code data from at least some of the packets;
• receiving the video clock on the video clock channel;
• and
• regenerating the audio clock from the time code data and the video clock.

A communication system, including:

• a receiver;
• a transmitter;
• and
• a serial link comprising at least one video channel between the transmitter and the receiver, wherein the transmitter is configured to receive video data and audio data, to generate encoded video data and encoded audio data by encoding the video data and audio data, to transmit code words indicative of the encoded video data over the video channel to the receiver in response to a first clock during active video periods, and to transmit packets including encoded auxiliary data to the receiver during data islands by transmitting code words indicative of the packets over the link in response to the first clock, wherein each of the data islands is a time interval that neither coincides with nor overlaps any of the active video periods,
• wherein the encoded auxiliary data include the encoded audio data, the transmitter is configured to include time code data in at least some of the packets, and the time code data together with the first clock are indicative of an audio clock for the audio data.