Picture coding apparatus and picture decoding apparatus

Abstract

A picture coding apparatus which generates a stream so as to be able to decode a picture by obtaining a picture parameter set necessary for decoding the picture even at the time of trick-play, the apparatus including: a slice coding unit which codes the picture and generates coded data; a picture parameter set (PPS) generation unit which generates sequence parameter set (SPS); a PPS generation unit which generates the PPS; and an access unit (AU) determination unit which stores pieces of coded data respectively into access units of a random access unit (RAU) and stores the SPS into a first AU, and stores the PPS into the first AU or into the AU in which one piece of the coded data that refers to the PPS is stored.

1 . A picture coding apparatus which (i) codes pictures, on a picture-by-picture basis, each including at least a pixel data storage unit for storing pixel data and a supplemental information storage unit, for storing supplemental information, being located ahead of the pixel data storage unit, and (ii) generates a random access unit, as a part of a stream, including the coded pictures, said picture coding apparatus comprising:
 a coding unit configured to generate a piece of coded pixel data by coding a piece of pixel data of each of the pictures;   a first information generation unit configured to generate sequence parameter set information which is a parameter group to be commonly referenced for decoding the pieces of coded pixel data included in the random access unit;   a second information generation unit configured to generate, for each piece of coded pixel data, a piece of picture parameter set information which is a parameter group to be referenced for decoding each piece of the coded pixel data, and to code the generated pieces of picture parameter set information;   a first storage unit configured to store the piece of the coded pixel data in each of pixel data storage units;   a second storage unit configured to store the sequence parameter set information of a supplemental information storage unit, of a starting picture, out of supplemental information storage units; and   a third storage unit, based on a predetermined condition, configured to store the coded piece of picture parameter set information in either (i) the supplemental information storage unit of the starting picture out of the pictures, or (ii) a supplemental information storage unit of a picture including the piece of coded pixel data that references the coded piece of picture parameter set information,   wherein said third storage unit is configured to store the coded pieces of picture parameter set information in the supplemental information storage unit of the starting picture, and to limit the number of the coded pieces of the picture parameter set information stored in the supplemental information storage unit of the starting picture, and   in a supplemental information storage unit of a coded picture except the starting picture, either (i) a coded piece of picture parameter set information to which the coded picture references is stored, or (ii) none of the coded pieces of picture parameter set information are stored.   
   
   
       2 . A picture coding method for (i) coding pictures, on a picture-by-picture basis, each including at least a pixel data storage unit for storing pixel data and a supplemental information storage unit, for storing supplemental information, being located ahead of the pixel data storage unit, and (ii) generating a random access unit, as a part of a stream, including the coded pictures, said picture coding method comprising:
 generating a piece of coded pixel data by coding a piece of pixel data of each of the pictures;   generating sequence parameter set information which is a parameter group to be commonly referenced for decoding the pieces of coded pixel data included in the random access unit;   generating, for each piece of coded pixel data, a piece of picture parameter set information which is a parameter group to be referenced for decoding each piece of the coded pixel data, and to code the generated pieces of picture parameter set information;   storing the piece of the coded pixel data in each of pixel data storage units;   storing the sequence parameter set information in a supplemental information storage unit, of a starting picture, out of supplemental information storage units; and   storing, based on a predetermined condition, the coded piece of picture parameter set information in either (i) the supplemental information storage unit of the starting picture out of the pictures, or (ii) a supplemental information storage unit of a picture including the piece of coded pixel data that references the coded piece of picture parameter set information,   wherein said storing the coded pieces of picture parameter set information involves storing the coded pieces of picture parameter information in the supplemental information storage unit of the starting picture, and limiting the number of the coded pieces of the picture parameter set information stored in the supplemental information storage unit of the starting picture, and   
     in a supplemental information storage unit of a coded picture except the starting picture, either (i) a coded piece of picture parameter set information to which the coded picture references is stored, or (ii) none of the coded pieces of picture parameter set information is stored. 
   
   
       3 . A picture decoding apparatus which decodes coded pictures out of the stream generated by said picture coding apparatus according to  claim 1 , said picture decoding apparatus comprising:
 a picture specification unit configured to specify a picture to be decoded out of the coded pictures;   a first obtainment unit configured to obtain, from a supplemental information storage unit of a starting picture, coded sequence parameter set information which is a parameter group to be commonly referenced for decoding pieces of coded pixel data included in the random access unit;   a second obtainment unit configured to obtain coded pieces of picture parameter set information, each of which is a parameter group to be referenced for decoding each piece of the coded pixel data to be decoded, the coded piece of picture parameter set information being obtained from either (i) the supplemental information storage unit of the starting picture out of the coded pictures, or (ii) a supplemental information storage unit of the picture to be decoded out of the coded pictures;   a first decoding unit configured to decode the coded sequence parameter set information;   a second decoding unit configured to decode the coded pieces of picture parameter set information; and   a third decoding unit configured to decode the piece of the coded pixel data to be decoded by referencing the decoded sequence parameter set information and the decoded one of pieces of picture parameter set information.   
   
   
       4 . A picture decoding method for decoding coded pictures out of the stream generated by said picture coding apparatus according to  claim 1 , said picture decoding method comprising:
 specifying a picture to be decoded out of the coded pictures; obtaining, from a supplemental information storage unit of a starting picture, coded sequence parameter set information which is a parameter group to be commonly referenced for decoding pieces of coded pixel data included in the random access unit;   obtaining coded pieces of picture parameter set information, each of which is a parameter group to be referenced for decoding each piece of the coded pixel data to be decoded, the coded piece of picture parameter set information being obtained from either (i) the supplemental information storage unit of the starting picture out of the coded pictures, or (ii) a supplemental information storage unit of the picture to be decoded out of the coded pictures;   decoding the coded pieces of sequence parameter set information;   decoding the coded pieces of picture parameter set information; and   decoding the piece of the coded pixel data to be decoded by referencing the decoded sequence parameter set information and the decoded one of pieces of picture parameter set information.   
   
   
       5 . A recording method for (i) coding pictures, on a picture-by-picture basis, each including at least a pixel data storage unit for storing pixel data and a supplemental information storage unit, for storing supplemental information, being located ahead of the pixel data storage unit, and (ii) recording a stream having in a part a random access unit including coded pictures in a computer-readable recording medium, said recording method comprising:
 generating a piece of coded pixel data by coding a piece of pixel data of each of the pictures;   generating sequence parameter set information which is a parameter group to be commonly referenced for decoding the pieces of coded pixel data included in the random access unit;   generating, for each piece of coded pixel data, a piece of picture parameter set information which is a parameter group to be referenced for decoding each piece of the coded pixel data, and to code the generated pieces of picture parameter set information;   storing the piece of the coded pixel data in each of pixel data storage units;   storing the sequence parameter set information in a supplemental information storage unit, of a starting picture, out of supplemental information storage units; and   storing, based on a predetermined condition, the coded piece of picture parameter set information in either (i) the supplemental information storage unit of the starting picture out of the pictures, or (ii) a supplemental information storage unit of a picture including the piece of coded pixel data that references the coded piece of picture parameter set information,   wherein said storing the coded pieces of picture parameter set information involves storing the coded pieces of picture parameter information in the supplemental information storage unit of the starting picture, and limiting the number of the coded pieces of the picture parameter set information stored in the supplemental information storage unit of the starting picture, and   in a supplemental information storage unit of a coded picture except the starting picture, either (i) a coded piece of picture parameter set information to which the coded picture references is stored, or (ii) none of the coded pieces of picture parameter set information is stored.