Abstract:
The method and apparatus for reproducing data from a disk receives at least video data read from a disk such as a digital video disk or a digital versatile disk. At least a portion of the video data is then processed to produce image data such that different camera angle images are simultaneously displayed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method for reproducing signals from a disc; and more particularly, for reproducing multiple camera-angle signals from a Digital Versatile Disc or Digital Video Disc (DVD). 
     2. Description of Related Art 
     A DVD is manufactured by masking image signals into digital form, and allows for many diverse functions. For instance, the image signals for multiple camera angles may be recorded on a DVD. 
     FIG. 2 illustrates, conceptually, the arrangement of data on a DVD. As shown, the image data representing a scene for each camera angle are grouped into angle blocks. Angle block  1 , for instance, includes the image data for each camera angle of the first scene. 
     FIGS. 3A-3E illustrate the data format of the image data stored on the DVD. As shown in FIGS. 3A and 3B, predetermined amounts of image data are each represented by a Video Object Set (VOB) and collectively as Video Object Sets (VOBS). A VOB consists of multiple cells of image data as shown in FIG.  3 C. Each cell in a VOB corresponds to an angle block as shown in FIG. 2, and includes image data for a scene. Also, each cell consists of a plurality of Video Object Units (VOBU) as shown in FIG.  3 D. Because scenes have different amounts of data, the amount of data in different cells can differ. 
     Each VOBU consists of a navigation packet (NV PCK), a plurality of video packets (V PCK), and an audio packet (A PCK) as shown in FIG. 3E. A navigation packet includes navigation data regarding, for instance, the video data stored in the video packets. The video data stored in video packets is encoded according to the well-known MPEG standard. 
     A conventional DVD reproducing apparatus reproduces the digital data recorded on a DVD. When the image signals for multiple camera angles (e.g., nine camera angles) are recorded on a DVD, a conventional DVD reproducing apparatus allows a user to select one of the images corresponding to one of the camera angles for viewing as shown in FIG.  1 A. Specifically, the conventional DVD reproducing apparatus navigates from the video data for the selected camera angle in one angle block or cell to the video data for the selected camera angle in the next angle block or cell. If, the user changes camera angles, a jump is made as shown in FIGS. 2 and 3D to the video data in the next angle block or cell corresponding to the newly selected camera angle. Unfortunately, the conventional DVD reproducing apparatus does not allow simultaneous viewing of more than one camera angle. 
     As a result, a user must sequentially view the images corresponding to each camera angle to gain an appreciation of the differences between the camera angles. It is, however, not easy to gain an appreciation of the differences between the camera angles in this manner. Consequently, it is difficult for a user to select an optimal camera angle for viewing. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a reproducing method and apparatus which overcome the disadvantages and problems discussed above with respect to the conventional art. 
     Another object of the present invention is to provide a reproducing method and apparatus which simultaneously display image signals corresponding to a plurality of camera angles. 
     These and other objects are achieved by providing (a) receiving at least video data read from a disk; (b) processing at least a portion of said received video data to produce image data such that different camera angle images are simultaneously displayed. 
     These and other objects are further achieved by providing receiving means receiving at least video data read from a disk; and processing means for processing at least a portion of said video data to produce image data such that different camera angle images are simultaneously displayed. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1A illustrates the display of a single camera angle; 
     FIGS. 1B and 1C illustrate displays of multiple camera angles; 
     FIG. 2 illustrates, conceptually, the arrangement of data on a DVD; 
     FIGS. 3A-3E illustrate the data format of the video data stored on a DVD; 
     FIG. 4 illustrates the reproducing apparatus according to the present invention; 
     FIGS. 5A and 5B illustrate a flow chart of the reproducing process according to the present invention implemented by the reproducing apparatus of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 4 illustrates the reproducing apparatus according to the present invention. As shown in FIG. 4, a signal separator  201  receives a bit stream reproduced from a DVD. The signal separator  201  separates the bit stream into a video bit stream and an audio bit stream, sends the audio bit stream to an audio processor  208 , sends the video bit stream to a video selector  202 , and sends format or header information in the video bit stream to the microcomputer  210 . 
     The audio processor  208  generates an audio output from the audio bit stream. The microcomputer  210  also receives user input, and based on the format information and the user input generates servo control data and video control data. The servo control data is supplied to a servo controller  209  which controls focus and tracking of the data reproducing element (not shown) in a well-known manner. The video control data is supplied to the video selector  202 . 
     The video selector  202  processes the received video bit stream based on the video control data, and outputs a video bit stream to a video decoder  203 . The video decoder  203  stores the received video bit stream in a first memory  204 , and decodes the received video bit stream. The decoder  203  outputs the resulting decoded video data to a video synthesizer  205 . 
     Besides the decoded video data, the video synthesizer  205  also receives a portion of the video control data output by the micro-computer  210  from the video selector  202 . The video synthesizer  205  stores the decoded video data in a second memory  206 . Based on the stored video data and the video control data, the video synthesizer  205  generates image data. A video encoder  207  receives and encodes the image data for display. 
     Next, operation of the reproducing apparatus will be described in detail with respect to FIGS. 4,  5 A and  5 B. Referring to FIG. 5A, in step S 101 , the microcomputer  210  receives user input and determines therefrom whether a reproduction mode has been selected. 
     If a reproduction mode has not been selected, processing ends. If a reproduction mode has been selected, a bit stream is reproduced from a DVD. As shown in FIG. 4, the signal separator  201  receives the reproduced bit stream, separates the bit stream into a video bit stream and an audio bit stream, sends the audio bit stream to the audio processor  208 , sends the video bit stream to a video selector  202 , and sends format information in the video bit stream to the microcomputer  210 . 
     The microcomputer  210  determines from the format information whether the DVD stores video data for multiple camera angles in step S 102 . If the DVD does not store video data for multiple camera angles, processing ends. Otherwise, the microcomputer  210  determines the total number of camera angles which can be reproduced from the DVD based on the format information, and processing proceeds to step S 103 . In step S 103 , the microcomputer  210  determines from the user input, e.g., depression of a multi-angle key (not shown), whether the user has requested the display of multiple camera angles. If so, processing proceeds to step S 104 ; otherwise, processing ends. 
     In step S 104 , the microcomputer  210  determines based on user input whether the user has selected all possible camera angles for simultaneous display. If so, processing proceeds to step S 105 ; otherwise, processing proceeds to step S 107 . In step S 107 , the microcomputer  210  communicates with the video synthesizer  205  via the video selector  202 , and instructs the video synthesizer  205  to display, for an allotted period of time, a message indicating the total number of camera angles which can be reproduced from the DVD. 
     Then, in step S 109  the microcomputer  210  determines whether the user has selected a total number of camera angles for display within a predetermined period of time. If a total number of camera angles for display has been selected, processing proceeds to step S 110 ; otherwise, processing returns to step S 107 . In step S 110 , the microcomputer  210  determines whether the user has entered camera angles for display within a predetermined period of time. If entered, processing proceeds to step Slll; otherwise, processing returns step S 107 . 
     Next, in step S 111 , the microcomputer  210  determines whether the number of camera angle numbers entered for display by the user in step S 110  equals the total number of camera angles for display entered by the user in step S 109 . If equal, processing proceeds to step S 105 ; otherwise, processing returns to step S 107 . 
     In step S 105 , one of the camera angles for display is selected for display in a highlighted format. The camera angle selected for display in the highlighted format (hereinafter “the highlighted camera angle”) is selected according to a default. For example, the camera angle assigned the lowest angle number is the default camera angle for display in the highlighted format. 
     Then, in step S 106 , the microcomputer  210  establishes display addresses for each camera angle to be displayed, and outputs the display addresses to the video synthesizer  205  via the video selector  202  so that the multiple camera angles will be displayed such as shown, for example, in FIGS. 1B and 1C. In step S 112 , the microcomputer  210  determines based on user input whether the user wants to change the highlighted camera angle. If so, processing proceeds to step S 118 ; otherwise, processing proceeds to step S 113 . In step S 118 , the user enters the number of a camera angle to be displayed in the highlighted format. If this number matches one of the camera angles to be displayed, then the user input is accepted and processing proceeds to step S 113 . Otherwise, the user input is not accepted, and processing does not proceed to step S 113  until an acceptable camera angle number is input. 
     In step S 113 , the first camera angle to be processed for the multiple camera angle display is set as camera angle number one when all available camera angles were selected for display in step S 104 , and is set as the lowest camera angle number entered by the user in step S 110  if all available camera angles were not selected for display in step S 104 . Then in step S 114 , the microcomputer  210  causes the video selector  202  to output data from the VOBUs in the cell corresponding to the camera angle to be processed. Specifically, the microcomputer  210  instructs the video selector  202  to output only the minimum amount of data necessary to display an image from the VOBUs in a cell (i.e., the intra- or I-picture data). 
     The video decoder  203  temporarily stores this data in the first memory  204 , decodes the data, and outputs the decoded data to the video synthesizer  205 . The video synthesizer stores the decoded data in the second memory  206  based on the display addresses received from the microcomputer  210 . 
     This process is then repeated for each camera angle to be displayed in the multiple camera angle display. Namely, in step S 115 , the microcomputer  210  determines if the current camera angle to be displayed equals the highest numbered camera angle to be displayed. If not, processing proceeds to step S 117 ; otherwise, processing proceeds to step S 119 . In step S 117  the number of the camera angle to be displayed is increased by one if all available camera angles were selected for display in step S 104 . Alternatively, the number of the camera angle to be displayed is set to the next highest camera angle to be displayed, which was entered by the user in step S 110 , if all available camera angles were not selected for display in step S 104 . Steps S 114  and S 115  are then repeated. 
     Steps S 117 , S 114  and S 115  will continue to be repeated until the current camera angle to be displayed equals the highest number of a camera angle to be displayed. When this occurs, processing proceeds from step S 117  to step S 119 . 
     In step S 119 , the microcomputer  210  controls the servo controller  209  such that the audio data corresponding to the camera angle to be displayed in the highlighted format is reproduced. The video separator  201  outputs the reproduced audio data to the audio processor  208 . 
     In step S 123 , the audio processor  208  outputs the audio data corresponding to the highlighted camera angle, and the video synthesizer  205  generates image data for a multiple camera angle display based on the video data stored in the second memory. Each camera angle for display in the multiple camera angle display is positioned according to its storage location in the second memory (i.e., the display address). 
     Based on instructions received by the microcomputer  210  via the video separator  202 , the video synthesizer  205  generates the image data corresponding to the highlighted camera angle such that the highlighted camera angle is displayed in the highlighted format. 
     Additionally, in accordance with the instructions received from the microcomputer  210 , the video synthesizer  205  generates the image data such that the camera angle number for each camera angle in the multiple camera angle display appears in a portion of the multiple camera angle display corresponding to that camera angle number. Then, the video encoder  207  encodes the image data and outputs the encoded image data for display. 
     Processing proceeds to step S 125  and the microcomputer  210  determines whether the user has selected to stop multiple camera angle display. If multiple camera angle display has not been stopped, processing proceeds to step S 112 ; otherwise, processing proceeds to step S 126 . In step S 126 , the video and audio data corresponding to the camera angle displayed in the highlighted format is solely reproduced in the well-known manner. 
     Because the reproducing apparatus according to the present invention only reproduces the smallest amount of data from the VOBUs necessary to display an image, as opposed to reproducing all the video data in the VOBU, the video decoder  203  decodes a significantly less amount of data compared to conventional reproducing apparatuses. Therefore, the reproducing apparatus according to the present invention can simultaneously display multiple camera angles using a single decoder. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.