MXPA00007587A - Digital baseband interface for a dvd player - Google Patents

Abstract

Managing interoperability of digital devices such as a digital video disc player and a digital television interconnected via a digital bus is provided. This interoperability is based on the IEEE 1394 serial bus for the physical and link layers and makes use of AV/C or CAL as the control language. This invention provides for transferring a DVD subpicture that has been transformed into a bit-mapped on-screen display (OSD) format via an asynchronous channel of the interconnecting serial bus.

Description

- DIG ITAL BASE BAND NTERFAZ FOR U NA DIGITAL VIDEO DISC PLAYER FIELD OF THE I NVEN C ION This invention relates to a method for managing the interoperability of digital devices such as a digital video disc player and a digital television interconnected via a digital bus. More particularly, the invention includes a system for processing sub-images of digital video disc (DVD) by digital television. BACKGROUND OF THE I NVENTION Video signal processing systems that use storage media that has digitally compressed audio and video information recorded therein include, among other devices, a digital video disc player adapted to process information saved in accordance with the digital video disc (DVD) specification. The information on a disc with digital video disc format is recorded as discrete data packets, in accordance with the audio and video data compression standards, where the designated packets carry data associated with various streams of data, such as alternative video angles, audio tracks, sub-picture streams and navigation information. A video disc player that reads a disc with digital video disc format can be controlled to display certain data packets and skip others. A single disc can be identified to allow the reproduction of multiple camera angles, endings of stories, scenes according to the content of the classifications, etc. Digital video disc subimages are used as the graphical user interface (G U I) for these functions as they provide the user with the ability to select from one of several different videos on a disc. By using this capability, the digital video disc system can be used to prevent unauthorized access to information on a particular disc as well as to continuously provide multiple variations of a video title in accordance with user commands. The current digital video disc players mix the decoded sub-image information with the decoded video into a single analog video signal to transport to a television.

A device such as a digital video disc player can be coupled to other devices, such as a display device, an audio / video recording device, audio equipment and communicate with these other devices via a data bus. This communication occurs in accordance with a bus protocol. Examples of bus protocols include the Consumer Electronics Bus (CEBus) and the High Performance Serial Bus I EEE 1394. A bus protocol commonly allows the communication of information and control data. For example, the Consumer Electronics Bus control information is communicated in a "control channel" that has a protocol defined in the Electronic Industries Association (ELA) IS-60 specification. On an IEEE 1394 serial bus, the control information is usually passed using the asynchronous services of the serial bus. The control information for a particular application can be defined using a programming language such as, for example, Common Application Language (CAL) or AV / C. BRIEF DESCRIPTION OF THE INVENTION The invention resides, in part, in the inventor's recognition of the aforementioned problems associated with the processing of digital video disc sub-images and navigation control in digital television. Currently, digital video disc players process digitally compressed audio and video information stored in accordance with the digital video disc specification. This processing includes the conversion of compressed digital current to a standard signal (for example, an NTSC or PAL signal). A remote control device or the front panel of the digital video disc player is used to produce an "almost interactive" program. That is to say, in response to a user command, a digital video disk sub-image is generated and combined with the decoded program stream before converting the digital current to an NTSC signal. The digital video disc sub-image can be considered as a menu that identifies available user-initiated options. Navigation through the program is achieved in response to the selection of one of these options. Therefore, the navigation information can be considered as logic that is executed in response to the selection of one of the available options identified in the digital video disc sub-image. The video decoding could be done on a digital device, for example, a digital television (DTV) or a box on top of the device; however, it is difficult and expensive to mix the sub-image data with the video in the digital video disc player before it is transported to the digital apparatus. For simplicity and convenience of understanding, the remainder of the discussion of the present invention will include the use of a digital television although this invention may also be applied in a box on top of the apparatus. Currently, digital televisions do not support the encoded length-of-operation format that is used for digital video disc sub-images. The advent of digital television receivers eliminates the burden of converting the digital current produced in a digital video disc player to an NTSC signal, thus creating a unique ability to take advantage of the digital signal processing digital current in television digital. However, the additional requirement of decoding digital video disc sub-images and interpreting the digital video disc navigation information in digital television would greatly increase the cost and complexity of digital television. This invention also resides, in part, in providing an apparatus and method for solving the problems described.

The present invention provides for receiving, on a digital television, digital bitmap data representative of a digital video disc sub-image and combining the bitmap digital data with a stream of decoded content received from the digital video disk . Particularly, the present invention provides a method and apparatus for processing digital video signals to receive from a digital video disc player a stream of program content representative of a programmed event; decoding the stream of the content of the program to generate a signal suitable for deployment; receive digital data suitable for display from the digital video disc player associated with the current content of the program; and combining the digital data received from the digital video disc player and the content stream of the program to produce a signal representative of a combined image suitable for display. The content stream of the program comprises data configured in a compressed format. Another aspect of the present invention makes it possible to receive subsequent deployable digital data representative of an updated portion of the previously received digital data; and updating the pull-down image combined with the subsequent watertight data received to produce an updated combined pull-down image. The update step responds to a user input received by the digital video disc player. Another additional aspect of the present invention allows a system to control a digital video disc player interconnected by a digital bμs to a digital television. Particularly, the digital video disc player processes a stream of program content from a digitally compressed format received from a digital video disc received in the digital video disc player to generate an audio / video program stream and a current of sub-image; transmits the audio / video program stream to digital television via an asynchronous digital bus channel; processes the sub-image stream to generate expandable digital data (eg, bitmap screen display); and transmitting the digital data to digital television via an asynchronous channel of the digital bus. BRIEF DESCRIPTION OF THE DRAWINGS The invention can be better understood by referring to the accompanying drawings in which: Figure 1 shows, in the form of a simplified block diagram, a typical digital video disc player; Figure 2 shows, in the form of a simplified block diagram, a system illustrating the interoperability of the digital video disc player of Figure 1 employing the present invention; Figure 3 shows, in the form of a simplified block diagram, an alternative embodiment of the system shown in Figure 2; In the drawings, reference numbers that are identical in different figures indicate aspects that are the same or similar. DETAILED DESCRIPTION OF ITS B ISLES Use of the IEEE 1394 serial bus has been suggested for many applications in a Domestic Network environment. It has been discussed in the Video Electronics Standards Association (VESA) for use as a "completely domestic network". It has been built on the next-generation personal computers and will be used for many local peripherals including disk drives as well as digital audio / video consumer electronics devices such as digital televisions (DTVs) and digital video disc players. I EEE-1394 is a high-speed, low-cost serial bus developed for use as a peripheral or bus in the backplane. Some of the important aspects of the bus include: dynamic node address assignments, data speeds of 100, 200 and 400 Mbits / sec. , asynchronous and synchronous modes, balanced bus arbitration, and consistency with ISO / I EC 13213. Figure 1 is a block diagram showing the basic elements of a common digital video disc player 24. The construction and operation of These elements are known to those skilled in the art and will not be discussed in detail herein. The digital video disc player 24 comprises a motor and lifting assembly 26 which, under the control of the servo processor 29, rotates the disc and reads the information stored therein. The preamplifier 27 and the digital video disc data processing unit 28 translate the electrical pulses of the motor and survey assembly 26 into digital data that can be further processed by the digital audio / video decoding unit 30. The processing unit Digital video disc data 28 commonly performs functions such as demodulation, error correction and separation of the simple data read from the disk so that the data is in a format suitable for the decoding unit 30. Error correction may include data processing such as that associated with a Reed Solomon algorithm. The decoding unit 30 receives the demodulated, error-corrected and separated data, processes the data, and provides the appropriate audio and video signals to a display unit, such as an NTSC television set. Particularly, the decoding unit 30 comprises the data stream demultiplexer 32 which demultiplexes the data from the data processing unit 28 into a plurality of separate data streams, including a video stream, an audio stream and a sub stream. -image, and provides the data streams to their respective data decoders. The video decoder 31 receives the video stream and provides a video signal to the mixer 33. The sub-picture decoder 34 receives the sub-picture stream and provides data to the display display control (OSD) 35 which provides signals video on-screen display to the mixer 33. The combined video signal from the mixer 33 is provided to the NTSC / PAL encoder 42 which provides a video signal that complies with the appropriate video signal standard to a video display device, such as an NTSC television. The audio decoder 36 receives the audio streams from the data stream multiplexer 32 and provides the appropriate audio signals to an audio system. The microcontroller 40 controls the operation of the digital video disc player 24. The microcontroller 40 is coupled to the user control device 37, which may comprise infrared remote control devices, front panel buttons or the like, and translates data from the device control device 37 for controlling the operation of the different elements of the digital video disc player 24 described above. Commonly, the microcontroller 40 is also configured to control various access functions of the digital video disc player 24 including, but not limited to, parental lock, separation or decryption information and navigation data. The microcontroller 40 may be included in various forms, including, but not limited to, a dedicated integrated circuit, or a part of a decoder / controller unit. The combined video signal generated by the mixer 33 can be sent to the digital television via a digital I IEEE 1394 bus.

Unfortunately, the performance of the decoded and uncompressed video signal can degrade the operation of the system due to the bandwidth requirement of transferring this video signal via a digital bus I EEE 1394, 30 frames / second X 720 horizontal pixels X 480 vertical pixels X 24 bits / pixel = 250 Mbits / second. The bandwidth for the current IEEE 1394 serial buses is commonly limited to 200 Mbits / second. Even with a serial bus of 400 Mbits / sec undo, after subtracting the necessary bandwidth for the header, transferring these decoded and uncompressed video signals would be difficult. For comparison purposes, this bandwidth is correlated to approximately one sixth of the size of a decoded high definition television signal. As described in more detail below, the present invention resides in part to the recognition of this problem, and in part, to identifying a solution thereto. Today's digital televisions provide many benefits for digital video processing. Figure 2 defines a system 100 for providing interoperability between a digital video disc player 24 and a digital television 50 via a serial bus I EEE 1394 60. In this system 100, interoperability can be achieved by transferring compressed MPEG current from the digital video disc player 24 to an integral MPEG decoder with the digital television 50. Transferring digital video disc sub-images from the digital video disc player 24 to a digital television 50 can be achieved using one of several formats . For example, a subset of HTM L without the navigation functions can be used to describe the screen display. Another possibility is to use a length-of-operation encoding format that is similar to the digital video disc sub-image format. However, the preferred embodiment includes transferring the actual information in a bitmap format of screen display. For example, a 640X480 full-screen display of 8 bits / pixel can be transferred in approximately 100 milliseconds using 10% of the IEEE 1394 serial bus bandwidth of 200 Mbps. The following describes the conversion of digital video disc sub-images to an on-screen display bitmap format and the transfer of the on-screen display bitmap sub-image directly from the video disc player digital 24 to digital television 50 via an asynchronous channel of the 60-series bus, for example, using a "pull" method. The digital video disc player 24 processes the digitally compressed audio and video information stored on the video disc thereby generating a digital current in an MPEG-PS (program stream) format. In one embodiment of the present invention the MPEG-PS stream is first converted to an MPEG-TS (transport stream) format by the PS to TS converter 39. The digital audio / video stream is transferred to the digital television 50 using an IEEE 1394 serial bus isochronous channel 60. The on-screen display bitmap sub-image is not transferred as a composite compressed M PEG video stream, but is transferred as a screen display in the form of bitmap wherein the screen display may be superimposed on the digital television 50 with the decoded MPEG audio / video stream before being displayed. The transfer of compressed MPEG-TS data via the digital bus eliminates performance and processing problems. Digital television can contain an MPEG Audio / Video Decoder that will be used to decode the MPEG-TS stream. The user will still interact directly with the digital video disc player 24 using the respective user control device 37 (i.e., front panel or remote control). The responses of this user interaction are handled in the digital video disc player 24 by decoding the MPEG sub-images and generating an on-screen display of bitmap sub-images. The display on the bitmap screen can be transferred via an asynchronous channel of the IEEE 1394 serial bus 60 to the on-screen display buffer located on the digital television 50. The bitmap image is superimposed, in the digital television, with the decoded MPEG video signal. Then the combined (or superimposed) signal is displayed. Figure 3 shows an alternative embodiment of the present invention wherein the MPEG-PS stream is decoded directly by the MPEG decoder in the digital television. MPEG-PS currents require less processing power than MPEG-TS currents; therefore, transmission decoders with sufficient packet buffers using demultiplexing software could be programmed to directly decode MPEG-PS streams. Therefore, the PS to TS converter 39 is not required. The audio / video content stream in an MPEG-PS format is transferred in an isochronous channel of the serial bus I EEE 1394 60 to an MPEG decoder in the digital television 50. Utilizing a bitmap format for bus transfer in digital video disc sub-images allows (1) the manufacturer of digital video discs to maintain the "look and feel" aspect of the sub-image, (2) there is freedom in the generation of the sub-image and (3) that there are dynamic updates (ie, partial screen or even updates of a pixel are possible). Compared to compressed representations, the bitmap representation requires less processing time for deployment because deploying these sub-images as a bitmap requires minimal interpretation and manipulation. Descriptive approaches, such as HTML, have the disadvantage of being difficult to specify and update for typical consumer products. To simplify the transfer of sub-images in the form of a bitmap, a "Pull" method is preferably used. With this method, the body of the bitmap data is transferred from the digital video disc player 24 to the digital television 50 using the asynchronous channel of the I EEE 1394 digital bus. The digital television 50 reads the map data of the peripheral device memory (ie, the digital video disc player) using at least one IEEE 1394 block read transaction. The display device is informed of the location and size of the devices. bitmap data via a "trigger" command that is sent from the digital video disc player 24 to the digital television 50 when the digital video disc player 24 is ready to begin transferring data. Other alternatives for transferring sub-images of the digital video disc player 24 to the digital television 50 include; (1) an asynchronous push method that mainly uses IEEE 1394 asynchronous write transactions initiated by the digital video disc player 24 to write the bitmap data on the digital television 50, (2) an isochronous transport method for transmit the bitmap data in one of the isochronous channels provided by I EEE 1394; (3) an asynchronous current method for transporting the sub-images and (4) alternatively, the bitmap data could be provided via a remixed channel 8 VSB-T (grid) or 16 RF VSB.

Once the sub-image is ready for transfer, the digital video disc 24 sends a trigger message to the digital television 50. A single trigger message 22 can be used for each sub-image. The start of a block transfer usually occurs through the use of a trigger message from the digital video disc 24 to the digital television 50. A queue can be implemented in the display device so that the messages of shots are processed in the same order in which they are received. After a trigger message is received from the target, the display module on digital television 50 requests memopa accesses (i.e., asynchronous readings) starting at the memory location specified in the message. The deployment device reads all of the information associated with the sub-image and begins to build the actual bitmap information. At the same time, it informs the digital video disk 24 that the block has been set so that the digital video disk 24 can release any memory that has been assigned to the transfer of this data block. Then this sub-image is displayed. The on-screen display controller of the digital television 50 (not shown) uses this data to build the screen display and mix it with the M PEG video decoded on the digital television 50. The time required for the transfer of map data of bits through the digital bus can be calculated as indicated below. For example, all data required for a 640X480 display with 4 bits / pixel requires 1, 228, 800 bits. All these data can be transferred in approximately 1 50 thousandths of a second assuming a 100 Mb / sec bus, a packet payload of 512 bytes and assuming that one packet can be transmitted every 500 micro seconds. This time is further reduced when it is considered that no screen display takes up much space. Using only one quarter (typical) of the entire screen produces approximately 40 ms of transfer time. Small updates can be of the order of a few thousandths of a second. Application Control Languages For a consumer electronic device to interact with other interconnected devices via a serial bus I EEE 1394, a common series of commands must be defined. Three standard approaches to modeling and control are Common Application Language, AV / C and the approach adopted for the Universal Serial Bus (USB). The design of control languages is based on the assumption that all consumer electronics products have a hierarchical structure of common parts or functions. Common Application Language and AV / C are control languages that distinguish between logical and physical entities. For example, a television (i.e., a physical entity) may have a number of functional components (i.e., logical entities) such as a tuner, an audio amplifier, etc. These control languages provide two main functions: Resource allocation and Control. The allocation of resources refers to requesting, using and releasing Red Generic resources. The messages and control are transported by FCP as defined in I EC-61883 and as mentioned above. for example. The Common Application Language has adopted an object-based methodology for its command syntax. An object contains and has unique access to a set number of internal values known as instance (IV) variables. Each object maintains an internal list of methods. A method is an action that an object performs as a result of receiving a message. When a method is invoked, one or more instance variables are usually updated. A message may include a method identifier followed by zero or more parameters. When an object receives a method, it looks in its list of methods for one that matches the method identified in the message. If you find it, the method will be executed. The parameters provided with the message determine the exact execution of the method. For an implementation of the Common Application Language, all devices that are able to display on-screen displays must implement the following display object on the screen. This object assumes JALAR Asynchronous with the trigger message approach. This object will be transported in the firing message of the digital video disc 24 to the digital television 50. Then, the digital television 50 will pull the menu by reading it from the bitmap memory space of the digital video disc 24. The response of this The application will be used by the digital video disk 24 as an indication that the display device has read these update blocks. Screen Deployment Update Shooting Object Although an exemplary embodiment is described with reference to a digital video device adapted to read compressed audio and video data from a disc and to process the data in accordance with the digital video disc specification, it should be understood that the present invention can be used in any video processing apparatus capable of processing digital audio and video information, wherein the information related to the program included with the audio and video information can be used to selectively restrict the reproduction of certain audio and video information on the disc. Although the invention has been described in detail with respect to numerous modalities thereof, it will be evident that by reading and understanding the above, numerous alterations to the described modality will occur to those skilled in the art and it is intended to include said alterations. in the scope of the appended claims. For example, the invention has been described with respect to digital video disc players, however this invention is also applicable to any digital device that processes at least one compressed digital data stream.

Claims (7)

1. REVIVAL DICATIONS l. A method for operating a digital video disc player interconnected by a digital bus to a digital video processing apparatus, the real digital video processing apparatus takes the steps of: (a) receiving from a digital video disc reproducer a stream of program content representative of a scheduled event, the said content stream of the program includes data in a compressed format; (b) decoding said stream of program content in said digitized device l; characterized by: (c) receiving from the aforementioned digital video disc player bitmap data representative of a sub-image associated with such stream of program content, said bitmap data being suitable for display; and (d) combining, in said digital apparatus, such bitmap data received from said digital video disc player and said content stream from the decoded program to produce a signal representative of a combined image suitable for display. The method of claim 1, further characterized in that the digital apparatus performs the steps of: (a) receiving subsequent bitmap data representative of an updated portion of such previously received sub-image; and (b) updating, in response to a command initiated by the user received by such a digital video disc player, said image combined with such subsequent bitmap data received to produce an updated combined image suitable for deployment. 3. A digital television comprising: (a) means for receiving a stream of compressed digital data from a storage medium; (b) means for decoding such compressed digital data stream in said apparatus; characterized by: (c) means for receiving from said storage medium bitmap data associated with said compressed digital data stream; and (d) means for combining, in said apparatus, such received bitmap data and said video signal to produce a signal representative of a combined image suitable for deployment. The digital television of claim 3, further characterized by: (a) means for receiving subsequent bitmap data representative of an updated portion of such previously received bitmap data; (b) means for updating said image combined with such subsequent received bitmap data suitable for deployment, wherein said update means responds to the input of the user. 5. A method for operating a digital video disc player interconnected by a digital bus to a digital television, the digital video disc player performs the steps of: (a) receiving from a digital video disc coupled thereto a digital current MPEG-PS; characterized by: (b) converting said digital current from an MPEG-PS format to a digital current having an M EPG-TS format; and (c) transmitting said digital MPEG-TS current to said digital television via an isochronous channel of said digital bus. The method of claim 5, further characterized by (a) processing a sub-image stream associated with such MPEG-PS digital stream to generate bitmap digital data suitable for deployment; and (b) transmitting said digital data in bitmap via an asynchronous channel of such digital bus. The method of claim 6, further characterized by (a) receiving a command initiated by the user in response to such displayed bitmap digital data; (b) generating an updated sub-image stream in response to said command initiated by the user; (c) processing said updated sub-image stream to generate updated bitmap digital data; and (d) transmitting said digital data in updated bitmap.RESU MEN It is provided to handle interoperability of digital devices such as a digital video disc player and a digital television interconnected via a digital bus. This interoperability is based on the I EEE 1394 serial bus for the physical and link layers and uses AV / C or Common Application Language as the control language. This invention allows transferring a digital video disc sub-image that has been transformed into a bitmap display (OSD) format via an asynchronous channel of the interconnect serial bus.