Video decoding device and image display device

Abstract

To efficiently provide 2-dimensional display of 3-dimensional video stream. A video decoding device 100 includes a macro block selector 103 for sequentially selecting, as objects to be decoded, macro blocks belonging to a range required for 2-dimensional display, and a decoding unit 100 for sequentially decoding macro blocks selected by the macro block selector. Furthermore, the video decoding device includes a motion vector shift unit 108 for correcting, when a motion vector of a macro block selected by the macro block selector is referring to outside the range required for the 2-dimensional display, the reference indicated by the motion vector to be within the range required for the 2-dimensional display. Since the macro block selector performs block selection, the decoding unit skips processing of macro blocks which are not supposed to be 2-dimensionally displayed.

1 - 6 . (canceled) 
     
     
         7 . A decoding device receiving an input video stream having a first macro block group including a plurality of macro blocks for forming a first image, and a second macro block group including a plurality of macro blocks for forming a second image, formed on the same frame,
 the decoding device comprising:
 a macro block selector circuit for selecting, as objects to be decoded, macro blocks of one of the macro block groups; 
 a decoding circuit for decoding only the selected macro blocks; and 
 a motion vector shift circuit for supplying a motion vector of a selected macro block to the decoding circuit, 
   wherein the motion vector shift circuit is further configured to correct a reference indicated by the motion vector of the selected macro block when the motion vector refers to a macro block outside of the one macro block group.   
     
     
         8 . The decoding device according to  claim 7 , wherein, when the motion vector refers to a macro block outside of the one macro block group, the motion vector shift circuit corrects the reference so as to be within the one macro block group. 
     
     
         9 . The decoding device according to  claim 7 , wherein, when the motion vector refers to a macro block within the one macro block group, the motion vector shift circuit supplies the motion vector to the decoding circuit without correcting the reference. 
     
     
         10 . The decoding device according to  claim 7 , wherein the motion vector shift circuit is further configured to:
 determine whether the motion vector is referring to a macro block outside of the one macro block group;   determine the encoding system of the video stream; and   correct the reference based on a result of the determinations.   
     
     
         11 . The decoding device according to  claim 10 , wherein the macro block selector circuit specifies a range of macro blocks within the one macro block group required for a 2-dimensional display, and selects, as objects to be decoded, macro blocks belonging to the range. 
     
     
         12 . The decoding device according to  claim 11 ,
 wherein the first macro block group is a right-eye macro block group including a plurality of macro blocks for forming a right-eye image and the second macro block group is a left-eye macro block group including a plurality of macro blocks for forming a left-eye image, and   the image motion vector shift circuit determines whether or not the motion vector of a macro block selected by the macro block selector is referring to a macro block of the right-eye macro block group, and determines whether or not the video stream has been encoded in a side-by-side system or a top-and-bottom system, and   in the case where the motion vector of the macro block selected by the macro block selector circuit is referring to a macro block for forming a right-eye image, corrects, in accordance with the result of the determinations, the reference indicated by the motion vector to be within a range for the 2-dimensional display.   
     
     
         13 . The decoding device according to  claim 12 , wherein a variable-length decoder is disposed, in a preceding stage of the macro block selector circuit, for performing variable-length decoding processing in which partitions of a macro block can be analyzed. 
     
     
         14 . A method of decoding an input video stream having a first macro block group including a plurality of macro blocks for forming a first image, and a second macro block group including a plurality of macro blocks for forming a second image, formed on the same frame, comprising:
 selecting, as objects to be decoded, macro blocks of one of the first and second macro block groups;   decoding only the selected macro blocks at a decoding circuit; and   supplying a motion vector of a selected macro block to the decoding circuit,   wherein a reference indicated by the motion vector of the selected macro block is corrected before the motion vector is supplied to the decoding circuit when the motion vector refers to a macro block outside of the one macro block group.   
     
     
         15 . The decoding method according to  claim 14 , wherein when the motion vector refers to a macro block outside of the one macro block group, the reference is corrected so as to be within the one macro block group. 
     
     
         16 . The decoding method according to  claim 15 , wherein when the motion vector refers to a macro block within the one macro block group, the motion vector is supplied to the decoding circuit without correcting the reference. 
     
     
         17 . The decoding method according to  claim 14 , further comprising:
 determining whether the motion vector is referring to a macro block outside of the one macro block group;   determining an encoding system of the input video stream; and   correcting the reference based on the determinations.   
     
     
         18 . The decoding method according to  claim 17 , wherein the input video stream is a 3-dimensional video stream, the first macro block group is a right-eye macro block group including a plurality of macro blocks for forming a right-eye image and the second macro block group is a left-eye macro block group including a plurality of macro blocks for forming a left-eye image. 
     
     
         19 . The decoding method according to  claim 18 , further comprising:
 specifying a range of macro blocks required for a  2 -dimensional display; and   selecting, as the objects to be decoded, macro blocks belonging to the range.   
     
     
         20 . The decoding method according to  claim 19 , wherein the specifying is based on the encoding system of the input video stream. 
     
     
         21 . The decoding method according to  claim 20 ,
 wherein the determining whether the motion vector is referring to a macro block outside of the one macro block group includes determining whether or not the motion vector is referring to a macro block of the right-eye macro block group, and the determining the encoding system of the input video stream includes determining whether or not the video stream has been encoded in a side-by-side system or a top-and-bottom system,   the method further comprising correcting, in a case where the motion vector of the selected macro block is referring to a macro block for forming a right-eye image, the reference indicated by the motion vector so as to be within the range for the 2-dimensional display, the correcting being in accordance with a result of the determinations.   
     
     
         22 . A method of decoding an input 3-dimensional video stream having a right-eye macro block group including a plurality of macro blocks for forming a right-eye image, and a left-eye macro block group including a plurality of macro blocks for forming a left-eye image, the method comprising:
 selecting macro blocks belonging to a single macro block group, the single micro-block group being the left-eye macro block group or the right-eye macro block group, as objects to be decoded;   supplying the selected macro blocks to a decoding circuit for decoding;   determining a first motion vector for one of the selected macro blocks; and   supplying a second motion vector to the decoding circuit based on the first motion vector,   wherein, when the first motion vector refers to a macro block belonging to the single macro block group, the second motion vector is supplied to the decoding circuit without shifting the first motion vector, and   wherein, when the first motion vector refers to a macro block belonging to the other macro block group, the second motion vector is supplied to the decoding circuit by first shifting the first motion vector.   
     
     
         23 . The decoding method according to  claim 22 , wherein the shifting includes shifting the first motion vector so as to be within the single macro block group. 
     
     
         24 . The decoding method according to  claim 23 , further comprising acquiring a predicted image based on the second motion vector. 
     
     
         25 . The decoding method of  claim 24 , further comprising:
 extracting decoded data belonging to the single macro block group based on the second motion vector; and   acquiring the predicted image based on the extracted decoded data.   
     
     
         26 . The decoding method of  claim 25 , further comprising:
 checking whether the first motion vector refers to a macro block belonging to the other macro block group after receipt of a control signal instructing for a 2-dimensional display; and   not checking whether the first motion vector refers to a macro block belonging to the other macro block group after receipt of a control signal instructing for a  3 -dimensional display,   wherein the macro blocks belonging to the other macro block group are not supplied to the decoding circuit.