Abstract:
A method for playing DVD. A method for simultaneously outputting a DVD movie to multiple channels each having its own playback parameters such as view angle, spoken language and subtitle language, using a single DVD player.

Description:
BACKGROUND 
     The invention is related to a method of DVD play, and in particular, to a method of simultaneously outputting a DVD movie stream to multiple channels of one DVD player each comprising individual playback parameters. 
     According to digital versatile disc (DVD) specifications, a disc may provide a movie with support for several languages, thus various playback parameters, such as a subtitle language, a spoken language and a view angle may be selected as desired. Although various options are provided, only one option can be implemented per viewing. That is to say, no more than one subtitle language, one spoken language and one view angle can be implemented at one time. 
     Conventional implementation of DVD options on a per viewing basis are adequate for general use, however, certain environments may require additional functionality. Such environments may include a plane, bus or Karaoke bar. Typically, a DVD player can play one DVD with specific playback parameters, thus, no all audiences requiring various native languages or preferring different view angles will be satisfied. If multiple DVD players, however, are provided to meet various requirements, cost is increased. 
     SUMMARY 
     An embodiment of the invention provides a method for synchronous output of multiple channels from one DVD player, wherein each channel comprises at least a selectable parameter, the method comprises the following steps. First, a plurality of channels are provided, each corresponding to a display. Parameter selections are received from each channel. Selected streams are generated by converting an original stream according to each selected parameter. Each selected stream is output on the corresponding display through channels from which the selected parameters are originated. 
     The original stream is obtained from a DVD. The parameter comprises a video option for selecting view angles, an audio option for selecting spoken languages, and a subtitle option for selecting subtitle languages. 
     The original stream comprises a video stream comprising video sub-streams of different view angles, an audio stream comprising audio sub-streams of various languages, and a subtitle stream comprising subtitle sub-streams of various languages. 
     The generating step comprises the following steps. The original stream are decrypted into the video stream, the audio stream and the subtitle stream. The video stream is decoded into video sub-streams, the audio stream into audio sub-streams, and the subtitle stream into subtitle sub-streams. A selected stream is generated through combination of one of the video sub-streams, one the audio sub-streams and one of the subtitle sub-streams according to the selected parameters. 
     Another embodiment of the invention provides a multiplex DVD player for simultaneously playing a DVD over multi channels each having at least a playback parameter, an option selector for receiving selected playback parameters, and a multiplexer for synchronous outputting a plurality of selections from an original stream to the corresponding channels where the selections are originated. 
     The multiplex DVD player further comprises a DVD reader for reading the original stream from a DVD, a decoder for decrypting the original stream to obtain the following data: a video stream comprising video sub-streams of different view angles, an audio stream comprising audio sub-streams of various languages, and a subtitle stream comprising subtitle sub-streams of various languages. The multiplex DVD player also comprises a video decoder for decoding the video stream into video sub-streams, an audio decoder for decoding the audio stream into audio sub-streams, and a subtitle decoder for decoding the subtitle stream to obtain the subtitle sub-streams. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description, given by way of example and not intended to limit the invention solely to the embodiments described herein, will best be understood in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a multiplex DVD player according to embodiments of the invention; 
         FIG. 2  is a diagram of a multiplexer according to an embodiment of the invention; 
         FIG. 3  shows an option selector and the data structure of the parameter according to an embodiment of the invention; 
         FIG. 4  is a flowchart showing DVD playback; 
         FIG. 5   a  and  FIG. 5   b  shows stream decryption. 
         FIG. 6  shows a DVD stream embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A detailed description of an embodiment of the invention is provided in the following. 
       FIG. 1  shows a DVD player  102  according to an embodiment of the invention. In DVD player  102 , an original stream  205  is obtained by reading a DVD  101  through a DVD reader  106 . The stream is then processed in a multiplexer  105  to generate a plurality of output streams  207 . Each output stream  207  is output through a corresponding output interface  107  and is transmitted to a corresponding client terminal  104  for presentation. Each client terminal  104  provides a set of playback parameters  305  for determining the received output stream  207 . The playback parameters  305  are entered to the DVD player  102  via a selection panel  103 . The selection panel  103  outputs the collected playback parameters  304  to control the multiplexer  105  and thereby the output streams  207  are generated individually. 
     The DVD  101  can be an optical storage media conforming to the digital versatile disc (DVD) format. 
     After processing in the multiplexer  105 , each output stream  207  can comprise the same or different data, depending on the language, subtitle, and view angle playback parameters (contained in  304 ) entered via the selection panel  103 , for display on the client terminal  104 . 
     Synchronous output of multiple output streams  207 , via multiple output interfaces  107 , regardless of the selected playback parameters  304 , corresponding to each stream, can be achieved as only one DVD player  102  is employed. 
       FIG. 2  is a detailed diagram of multiplexer  105 , wherein the original stream  205  is received by a stream engine  206  and decrypted to video stream  601 , audio stream  602  and subtitle stream  603  which are further decoded to video sub-stream  501 , audio sub-stream  502  and subtitle sub-stream  503  through video decoder  201 , audio decoder  202  and subtitle decoder  203 . In multiplexer  208 , the playback parameters  304  are input and the output streams  207  are accordingly generated through recombination of video sub-stream  501 , audio sub-stream  502  and subtitle sub-stream  503 . 
     The sets of playback parameters  305  can be input via remote control. In an embodiment of the invention shown in  FIG. 3 , the selection panel  103  comprises a panel for each client terminal  104  for entering the set of playback parameters  305  corresponding thereto. Each output stream  207  corresponds to one set of playback parameters  305 . One set of playback parameters  305  comprises subtitle selection  301 , speech selection  302  and view angle selection  303 , but is not limited thereto, instead, highly personalized features may be provided to improve playback quality, such as brightness, screen ratio (3:4 or 9:16), volume effects (mono, stereo or surround) and the like. 
       FIG. 6  shows a DVD data structure. An original stream  205  comprises digital content of various data types, such as video stream  601 , audio stream  602  and subtitle stream  603 , which are interleaved and repeated periodically. The physical positions of video stream  601 , audio stream  602  and subtitle stream  603  in the DVD are precisely represented as “ABC”, “XYZ” and “123” in  FIG. 6 . Therefore, the DVD player  102  reads the original stream  205  as a consecutive digital chain. The mechanism for decoding the chain is described in the following. The video stream  601  comprises a plurality of video sub-streams  501 , the audio stream  602  comprises a plurality of audio sub-streams  502 , and the subtitle stream  603  comprises a plurality of subtitle sub-streams  503 . All the streams are further decoded into a plurality of sub-streams. Similarly, when “ABC” (video stream  601 ) is decoded from the chain “ABCXYZ123” (original stream  205 ), it is further decoded to obtain “A” “B” and “C”, as video sub-stream  501 . 
       FIG. 5   a  and  FIG. 5   b  shows the entire stream process. An original stream  205  is decrypted in stream engine  206 , the generated video stream  601 , audio stream  602  and subtitle stream  603  are then further decoded by video decoder  201 , audio decoder  202  and subtitle decoder  203 , obtaining video sub-stream  501 , audio sub-stream  502  and subtitle sub-stream  503 . In  FIG. 5   b , a plurality of video channel  701 , audio channel  702  and subtitle channel  703  are provided for receiving video sub-stream  501 , audio sub-stream  502  and subtitle sub-stream  503 . The streams are recombined in the multiplexer  208 , through selection of one of video channels  701 , one of audio channels  702  and one of subtitle channels  703  according to the collected playback parameters  304 , and corresponding output streams  207  are generated and synchronously output to client terminal  104 , from which the collected playback parameters  304  originated. In practice, the multiplexer  208  may comprise four video channels  701 ; thirty two audio channels  702  and eight subtitle channels  703 , according to DVD specifications, and the stream engine  705  can be a chip or switch for switching electronic signals. 
     In another embodiment of the invention, the output interface  107  can be an RF node, an AV node, a RGB node or a digital video interface (DVI) node. The number of output interface  107  depends on the viewers. For example, a bus may require 20 nodes while a plane require as many as 400. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.