Abstract:
An apparatus comprising a drive server, a control server and one or more decoder devices. The drive server may be configured to present one or more compressed data streams in response to one or more first control signals. The control server may be configured to present one or more of the compressed data streams in response to (i) one or more request signals and (ii) the one or more compressed data streams. The decoder devices may be configured to present a decoded video signal and a decoded audio signal in response to (i) one or more second control signals and (ii) the one or more compressed data streams. The navigation software, which traditionally is processed local to the decoder, may be processed on the control server. The control server may be enabled to control the remote decoder.

Description:
FIELD OF THE INVENTION 
     The present invention relates to video on demand systems generally and, more particularly, to a video on demand DVD system. 
     BACKGROUND OF THE INVENTION 
     Conventional digital video disk (DVD) players are implemented as stand-alone systems. In a multi-user environment, such as a hotel (or apartment) complex, a separate DVD player would have to be implemented in each room. 
     Conventional video on demand (VOD) systems provide a centralized storage location that may present independent video and audio programming to a number of rooms. Such a conventional video on demand system is shown in FIG.  1 . Since conventional video on demand systems use S-video cables between the decoders and the monitors, the distance between the remote locations and the decoders can be hundreds of feet. However, with a DVD player, extensive decoding is included within the DVD players that prohibits use in a video on demand system. Additionally, personal computers (PCs) may implement DVD drives, but suffer from the same limitations of stand-alone players. Specifically, an individual PC would have to be dedicated to each room in the multi-user environment. 
     Video on demand systems used for MPEG1 VCD or MPEG2 titles are typically implemented as personal computers with peripheral connect interface (PCI) add-on cards that support four or more video decoders. The decoders are implemented centrally at the PC level. Such centralized systems are used with hotel video on demand systems. A drive running a title and a decoder are dedicated to each hotel room. The uncompressed video from the dedicated video compact disc (VCD) is wired to the room with, for example, S-Video cable. A separate cable allowing a remote control to control user options (e.g., stop, fast forward, rewind, etc.) is used as a feedback back to the player in the central location. 
     DVD titles use Macrovision copyright security as a required component encoded on each DVD player. When VOD systems are upgraded to support DVD, for applications where Macrovision copyright security on uncompressed video is not adequate, the infrastructure needs to be upgraded to a support compressed video feed to a decoder that resides in the room, but before the television. Macrovision application license restrictions include limiting the length of cable. It would be desirable to implement a DVD video on demand system without the requirement (and associated cost) of implementing a DVD Player for each remote location. 
     SUMMARY OF THE INVENTION 
     The present invention concerns an apparatus comprising a drive server, a control server and one or more decoder devices. The drive server may be configured to present one or more compressed data streams in response to one or more first control signals. The control server may be configured to present one or more of the compressed data streams in response to (i) one or more request signals and (ii) the one or more compressed data streams. The decoder devices may be configured to present a decoded video signal and a decoded audio signal in response to (i) one or more second control signals and (ii) the one or more compressed data streams. 
     The objects, features and advantages of the present invention include providing a video on demand DVD system that may (i) be enabled to have navigation software local to host server, while a remote source decoder is in another room, (ii) be enabled to control a remote source decoder directly, (iii) implement navigation software on a host server and/or (iv) implement a number of shared DVD drivers at a centralized location. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which: 
     FIG. 1 is a diagram of a conventional video on demand system; 
     FIG. 2 is a diagram of a preferred embodiment of the present invention; 
     FIG. 3 is a diagram of an alternate embodiment of the present invention; 
     FIG. 4 is a diagram of an alternate implementation of the decoder of FIG. 3; and 
     FIG. 5 is another alternate embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 2, a block diagram of a DVD video on demand system  100  is shown in accordance with a preferred embodiment of the present invention. The video on demand system  100  generally comprises a server  102  and a disk library  104 . The disk library  104  generally comprises one or more DVD drives and associated disks that present one or more signals to the server  102 . The server  102  may be implemented as a personal computer or other appropriate server. 
     The server  102  may present a number of compressed bitstreams (e.g., DVD bitstreams) at a number of outputs  110   a - 110   n  that may be received at a number of inputs  112   a - 112   n . The inputs  112   a - 112   n  are generally located in a number of individual remote decoders  114   a - 114   n , that may be located, in one example, in a set-top box. In another example, the remote decoders  114   a - 114   n  may be built into the tuner section of a television. In either implementation, the remote decoders  114   a - 114   n  may be located in one or more remote locations, such as rooms in a hotel or apartment. The remote decoders  114   a - 114   n  may be implemented, in another example, as a component of a multifunction decoding device (to be described in more detail in connection with FIG.  3 ). 
     Each of the remote decoders  114   a - 114   n  generally comprise a decoder portion (or circuit)  120 , a control portion (or circuit)  121 , a user options input interface  122 , and one or more buffers  124 . The control circuit  121  may be implemented as a host processor or state machine control device. The decoder  120  may present a decoded audio signal at an output  126  that is generally presented to one or more speakers  128 . The decoder  120  may also present a decoded video signal at an output  130  that may be presented to a video display  132  (e.g., a television screen or a computer monitor). The decoded audio signal may be a monophonic channel, a dolby digital two channel signal, a dolby digital 5.1 channel signal, a DTS 5.1 channel signal, or other appropriate single or multi-channel audio signal. In general, the audio signals presented at the output  126  are line level signals that may be presented to an audio amplifier (not shown) to power one or more speakers. The amplifier may be built into the display  132  or may be implemented as a separate multi-channel amplifier. 
     To upgrade a video on demand infrastructure, the decoder  120  is generally physically located within a few feet of the display device  132 . The compressed DVD bitstreams are generally feed to the remote decoders  114   a - 114   n  from the server  102 . The decoder  120  decodes the video and audio portions of compressed DVD bitstream. The navigation software (i.e., the software that controls functions such as fast forward, rewind, pause, etc.) may be implemented locally to the decoder  120 , similar to conventional DVD players. Alternately, since the video signals are generally received from a centralized server, the server  102  may be implemented to run all the navigation software. The navigation software may interpret user options (e.g., request signals) received from a user remote control (not shown). The request signals from the user remote control may be received from a separate cable that feeds back to the server  102 . The circuit  100  illustrates n cables connected between each of the outputs  110   a - 110   n  and each of the inputs  112   a - 112   n . Since such a cable system may already be in place, the only upgrade necessary may be the remote decoder  114  in the room, the navigation software running on the server, and the DVD drive server. 
     In one example, the decoder  120  may be implemented as a dedicated optimized hardware audio and video decoder. Additionally, the user options circuit  122  and the buffers circuit  124  may also be implemented on a single chip along with the decoder  120 . However, separate chip solutions may also be implemented to meet the design criteria of a particular implementation. 
     A cost savings may result by having the navigation software for all the decoders  120  in each of the remote decoders  114   a - 114   n  run on the server  102 . The user may be given a DVD control template to select a particular option. Since most of the processing may be done by the server  102 , the remaining needs for the remote decoders  114   a - 114   n  may be limited. For example, the remote decoders  114   a - 114   n  may need to receive the uncompressed video, via Universal Serial Bus (USB), 1394 bus or other appropriate interface/bus configuration. A feedback of the user options may be implemented, in one example, using the same control system previously used for VCD. Centralizing the navigation controls may greatly reduce memory and processor performance requirements for the remote decoders  114   a - 114   n , further reducing cost. 
     For the connections between the outputs  110   a - 110   n  and the inputs  112   a - 112   n , USB or 1394 may be needed, since DVD bitstreams have 2 to 10 Mbps data rate. One of a number of decoder navigation modules  150   a - 150   n  running on the server  102  may be dedicated to each remote decoder  114   a - 114   n . The control of the source decoder may be received from the buffers  124 . One or more simple state machines may control the read and write operations sent to the decoder  120  in each of the remote decoders  114   a - 114   n . The decoder  120  may include host registers as well as buffer interrupts (not shown). The control of the decoders  121   a - 121   n  may be embedded in the communication media and may be a different structure from the DVD bitstream, as in the case of USB or 1394. 
     The present invention may provide navigation software traditionally local to the DVD player or DVD PC at the server  102  of a VOD system, enabling low cost decoder boxes at destination televisions. The navigation software on the server  102  may parse the DVD bitstream and may process user options such that the remote decoders  114   a - 114   n  may be remotely controlled. The communication media between the server  102  and the remote decoders  114   a - 114   n  may support the DVD bitstream as well as the programming of the decoder  120 . Appropriate navigation software coding can readily be prepared by skilled programmers based on the teachings of the present disclosure, as will also be apparent to those skilled in the relevant art(s). 
     The present invention may enable a cost effective solution to DVD VOD systems. For example, if a DVD Player costs $500, and the per location solution of the present invention is $150 per location, a significant cost savings to implement DVD in each location may result. The present invention proposes bulk drives on capable servers, with a minimal cost in the remote decoders  114   a - 114   n.    
     Referring to FIG. 3, an alternate embodiment of the present invention is shown. A number of source devices  104   a - 104   n  are shown presented to the server  102 . One of the source devices (e.g.,  104   a ) may be a DVD ROM server as shown in FIG.  1 . However, an additional number of source devices  104   b - 104   n  may be implemented. For example, a source for digital television (DTV) may be implemented as the source  102   b , a source for a satellite may be implemented as the source  102   c  and a source for cable TV may be implemented as one of the sources  104   a - 104   n . The server  102  may be implemented to select between one of the sources  104   a - 104   n  to present data to a particular one of the outputs  110   a - 110   n . The remote decoders  114   a - 114   n  may be modified to decode the various sources  104   a - 104   n . In such an implementation, the present invention may enable a number of remote decoders  114   a - 114   n  to support a full spectrum of video and audio formats found in the various evolving multiple broadcast standards. Furthermore, with personal computers providing a number of multimedia functions as well as audio components providing a number of multimedia functions, convergence of various formats can be supported by the remote decoders  114   a - 114   n . For example, a MPEG-2 bitstream may be presented at the outputs  110   a - 110   n.    
     Additionally, the example illustrated in FIG. 3 may provide a number of decoder control circuits  151   a - 151   n . The a decoder control circuits  151   a - 151   n  may be optional circuits that may be used to control the particular navigation software elements  150   a - 150   n . Additionally, a decoder  153  may be implemented that may control each of the navigation software elements  150   a - 150   n . In one example, the decoder  114   a  may be connected to the decoder  114  through a universal serial bus or other appropriate interconnection  117 . 
     Referring to FIG. 4, an example of a multifunction remote decoder  114  is shown. The remote decoder  114  generally has an input  112  that may receive one of the number of sources  110   a - 110   n . A number of individual decoding elements  200   a - 200   n  may be provided to decode the particular source. The signal received at the input  112  may be presented to inputs of the various decoding elements  200   a - 200   n . The outputs of the decoder elements  200   a - 200   n  may be presented to an output  210  and an output  212 . A multiplexer (not shown) may be implemented to switch between the various outputs of the individual decoder elements  200   a - 200   n . In one example, the decoder elements  200   a - 200   n  may be implemented as a single integrated circuit. However, to provide flexibility for future standards, the individual decoder elements  200   a - 200   n  may be implemented as one or more integrated circuits. For example, if the remote decoder  114  is implemented to decode three current video/audio standards, a single chip implementing three individual decoders  200   a - 200   n  may be used. However, to implement a fourth standard, a second integrated circuit  114   a  may be implemented as a new decoder and may be configured to add to the existing decoders. The second integrated circuit  114   a  may be connected to the remote decoder  114  through, for example, a USB or 1394 connection  117 . 
     Remote programming of the decoder, independent of the local host processor may be done for diagnostic purposes, or to reduce cost on components. In one example, the USB or 1394 process may enable remote programming of the decoder and user options presented to server. 
     Referring to FIG. 5, an alternate implementation of the circuit  100  is shown. A number of source devices  104   a - 104   n  are shown presenting a number of input signals to the server  102 . Each of the devices  104   a - 104   n  may be configured to continuously play a number of source titles. A number of decoders may select any of the source devices  104   a - 104   n  at a particular time. The selection is generally within the constraints of the selected source  104   a - 104   n . Particularly, the bandwidth capabilities for handling multiple user navigations of a particular source  104   a - 104   n  must generally be met. If enough titles are implemented in enough sources  104   a - 104   n , the remote decoders  114   a - 114   n  may be able to select a particular title at a particular time. In order to solve the mentioned bandwidth capability issues, the same titles may be started at offset times, which may present the appearance of an unlimited selection of titles. In addition, a single bitstream may be sent to each of the decoders  114   a - 114   n  to initiate a diagnostics test. 
     When sending a single bitstream to a number of decoders  114   a - 114   n , a bandwidth of 20 Mb/sec can be implemented in certain DVD drives. In such an example, up to four decoders may be supported. For example, if a DVD drive can present a 9.8 Mb/sec bit rate, and the compressed bitstream is typically 4 Mb/sec, four decoders  114   a - 114   n  may be supported. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.