Method of and apparatus for utilizing extended AV/C command and response frames including transaction label and common result/error code
First Claim
1. A method of encoding a data packet with one or more extension fields, wherein the data packet substantially conforms to a standardized AV/C command or response data packet for transmitting the data packet over a network, the method comprising:
- a) providing a data packet with a control data frame having a fixed payload, wherein the control data frame comprises a sequence of data fields; and
b) providing extended fields data within at least one of the data fields, wherein the extended fields data encodes the data packet for the extension data field and includes a value representing a quantity of extension data included within the data packet, further wherein the value within the extended fields data comprises one byte of data including a first hexadecimal data value and a second hexadecimal data value and encodes the data packet to hold a number of extension data bytes, wherein the number of extension data bytes is determined such that when the first hexadecimal data value of the extended fields data is equal to eight, the second hexadecimal data value of the extended fields data equals the number of extension data bytes; and
when the first hexadecimal data value is equal to nine, the number of extension data bytes is fifteen plus the second hexadecimal data value.
1 Assignment
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Accused Products
Abstract
AV/C command and response data packets are used for asynchronous data block transactions between devices over an IEEE 1394-1995 serial bus network. Extension data fields hold extension data that support new or added features of an IEEE 1394-1995 serial bus network and devices operating therein. The AV/C data packets are encoded for the extension data fields by providing extended fields data within data fields of the Function Control Protocol (FCP) data frames. The extended fields data specifies whether or not the packet includes extension data fields, and if so, how many bytes of extension data may be included within the data field. Extension data supports device and system features such as transaction labels and error/result messages. Transaction data is used to determine the number of other extension data fields to be used during AV/C data transacted between devices and provides for the ability to establish communication protocols based on mutually supported features.
75 Citations
14 Claims
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1. A method of encoding a data packet with one or more extension fields, wherein the data packet substantially conforms to a standardized AV/C command or response data packet for transmitting the data packet over a network, the method comprising:
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a) providing a data packet with a control data frame having a fixed payload, wherein the control data frame comprises a sequence of data fields; and b) providing extended fields data within at least one of the data fields, wherein the extended fields data encodes the data packet for the extension data field and includes a value representing a quantity of extension data included within the data packet, further wherein the value within the extended fields data comprises one byte of data including a first hexadecimal data value and a second hexadecimal data value and encodes the data packet to hold a number of extension data bytes, wherein the number of extension data bytes is determined such that when the first hexadecimal data value of the extended fields data is equal to eight, the second hexadecimal data value of the extended fields data equals the number of extension data bytes; and
when the first hexadecimal data value is equal to nine, the number of extension data bytes is fifteen plus the second hexadecimal data value. - View Dependent Claims (2)
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3. A system for transmission of asynchronous AV/C command and response data over a standard IEEE 1394 serial bus, the system comprising:
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a) a control device in communication with the standard IEEE 1394 serial bus, the control device configured for generating a command data stream comprising at least one command data packet with a control data frame comprising control data fields and extension data for supporting the control device features; and b) a target device in communication with the standard IEEE 1394 serial bus, the target device configured for receiving the command data stream and generating a corresponding response data stream comprising at least one response data packet with a control data frame comprising target data fields wherein at least one of the target data fields is a response transaction label data field containing transaction label data that codes the response data stream for the compatibility of the target device with the command data stream received. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A system for transmission of asynchronous AV/C command and response data over a standard IEEE 1394 serial bus, the system comprising:
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a) a control device with features in communication with the standard IEEE 1394 serial bus, the control device configured for generating a command data stream comprising at least one command data packet with a control data frame comprising control data fields, wherein at least one of the control data fields comprises extended fields and extension data for supporting the control device features; and b) a target device in communication with the standard IEEE 1394 serial bus, the target device configured for receiving the command data stream and generating a response data stream comprising at least one response data packet with a control data frame comprising a target data field, wherein the target data field comprises features data providing a signature of features implemented at the target device, further wherein the control device is capable of adding or removing the extended fields data field for subsequently transmitted command data packets in the event that the target device does not support features encoded for therein. - View Dependent Claims (10, 11, 12)
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13. A method of establishing a communication protocol for the transmission of AV/C command and response data packets over an IEEE 1394 serial bus, the method comprising:
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a) submitting an AV/C command data packet from a control device over the serial bus to a target device, wherein the command data packet is formatted with extended fields data and extension fields for supporting features of the control device; b) detecting the extended fields data at the target device and generating a response data packet therefrom, wherein the response data packet provides a compatibility signature for control device features that are compatible with the target device; and c) transmitting the response data packet to the control device, wherein the control device reads the response data packet and formats subsequently transmitted command data packets transmitted to the target device to comprise extended fields data and extension data fields that support compatible features, further wherein when the response data packet contains an error message, extended fields data and extension data fields are removed from the subsequently transmitted command data packets.
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14. A method of establishing a communication protocol for the transmission of AV/C command and response data packets over an IEEE 1394 serial bus, the method comprising:
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a) submitting an AV/C command data packet from a control device over the serial bus to a target device, wherein the command data packet is formatted with extended fields data and extension fields for supporting features of the control device; b) detecting the extended fields data at the target device and generating a response data packet therefrom, wherein the response data packet provides a compatibility signature for control device features that are compatible with the target device; and c) transmitting the response data packet to the control device, wherein the control device reads the response data packet and formats subsequently transmitted command data packets transmitted to the target device to comprise extended fields data and extension data fields that support compatible features, further wherein an established communication protocol is stored by the target device to provide a history of the compatible device features.
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Specification