Method of and apparatus for supporting and enabling the selection and mixing of multiple streams of audio/video data from multiple sources within a receiving device allowing external control

#The present invention relates to the field of selecting and mixing data at a receiving device. More particularly, the present invention relates to the field of selecting and mixing streams of audio/video data at a receiving device to provide an output stream of data under control from an external device.

#The IEEE standard, “IEEE 1394-2000 Standard For A High Performance Serial Bus,” Draft ratified in 2000, is an international standard for implementing an inexpensive high-speed serial bus architecture which supports both asynchronous and isochronous format data transfers. Isochronous data transfers are real-time transfers which take place such that the time intervals between significant instances have the same duration at both the transmitting and receiving applications. Each packet of data transferred isochronously is transferred in its own time period. Ali example of an ideal application for the transfer of data isochronously would be from a video recorder to a television set. The video recorder records images and sounds and saves the data in discrete chunks or packets. The video recorder then transfers each packet, representing the image and sound recorded over a limited time period, during that time period, for display by the television set. The IEEE 1394-2000 serial bus architecture provides multiple channels for isochronous data transfer between applications. A six bit channel number is broadcast with the data to ensure reception by the appropriate application. This allows multiple applications to simultaneously transmit isochronous data across the bus structure. Asynchronous transfers are traditional data transfer operations which take place as soon as possible and transfer an amount of data from a source to a destination.

#The IEEE 1394-2000 standard provides a high-speed serial bus for interconnecting digital devices thereby providing a universal I/O connection. The IEEE 1394-2000 standard defines a digital interface for the applications thereby eliminating the need for an application to convert digital data to analog data before it is transmitted across the bus. Correspondingly, a receiving application will receive digital data from the bus, not analog data, and will therefore not be required to convert analog data to digital data. The cable required by the IEEE 1394-2000 standard is very thin in size compared to other bulkier cables used to connect such devices. Devices can be added and removed from an IEEE 1394-2000 bus while the bus is active. If a device is so added or removed the bus will then automatically reconfigure itself for transmitting data between the then existing nodes. A node is considered a logical entity with a unique address on the bus structure. Each node provides a configuration ROM, a standardized set of control registers and its own address space. Because of these advantages the IEEE 1394-2000 standard provides for a unique networking structure that is capable of incorporating audio/video devices, media play/record devices, computing devices and display devices.

#FIG. 1 illustrates a protocol defined by the IEEE 1394-2000 standard.

#FIG. 2 illustrates a block diagram of a conventional home audio/video network including a television and VCR.

#FIG. 3 illustrates a functional block diagram of an exemplary network of devices according to the present invention, including a first digital VCR, a second digital VCR, a computer system and a digital television.

#The method of and apparatus for supporting and enabling the selection and mixing of multiple input data streams from multiple sources within a receiving device allowing external control of the preferred embodiment of the present invention includes a receiving device, a control device and one or more source devices. The receiving device receives input data streams from the source devices. Preferably, the input data streams are streams of audio/video data and on-screen-display/graphics data. Alternatively, the input data streams are streams of any appropriate data type to be selected and mixed into an output stream by the receiving device. The input data streams are provided as inputs to selectors within the receiving device. The selectors output selective ones of the input data streams to a mixer, based on control input received from a control device. The selectors are turned off or on. When a selector is turned off, the selector will not output any input data stream. When a selector is turned on, the selector will output a selected one of the input data streams provided as inputs to the selector. The outputs from the selectors are provided to a mixer. The mixer then combines the selected input data streams into an output stream, based on control input received from the control device. The mixer can select one of the input data streams or can output some combination of the input data streams.

#Upon request from the control device, the receiving device exposes the functionality and controls of the selectors and the mixer to the control device, allowing the control device to provide control information to control the selectors and the mixer within the receiving device. As the control device receives control inputs, the control device provides control information to the selectors and the mixer within the receiving device to control the output of the input data streams. The control device receives the control inputs from any appropriate input devices including a remote control, keyboard, mouse or other devices coupled to the control device either by a wired or wireless connection. This allows the control device to control which input data streams are output, how the input data streams are output and how the input data streams are combined for output, if appropriate. Accordingly, for video data streams, the display of multiple input data streams can be selected, displayed together in a tiled format or in separate windows, such as a picture-in-picture format, and on-screen-display/graphics data can be overlaid on video input data streams. For audio data streams, the output of one or more audio source streams can be selected or the audio source streams can be combined together for output.

#A functional block diagram of an exemplary network of devices including a first digital VCR 80, a second digital VCR 100, a computer system 120 and a digital television 50 is illustrated in FIG. 3. Relevant functional components of the first digital VCR 80, the second digital VCR 100 and the digital television 50 are also illustrated in FIG. 3. The digital television 50 includes ail IEEE 1394-2000 interface circuit 76 through which data and commands are sent to and received from the digital VCR 80, the digital VCR 100 and the computer 120, over the IEEE 1394-2000 serial bus cables 126, 128 and 130, respectively.