Picture coding method and picture decoding method

摘要

In a picture coding method for generating a coded signal corresponding to each picture by coding a plurality of coded signals, a switching picture which is capable of switching a plurality of coded signals and subsequent pictures of the switching picture can refer to only a group of pictures of the same time in the coded signals. More specifically, the case where picture numbers of an adjacent picture of an S picture and the S picture are not continuous is not considered as an error.

主权项

1. A decoding method for decoding a coded signal which contains picture type information and a picture number to identify a reference picture stored in a memory, said method comprising:
obtaining picture type information from a first coded picture included in the coded signal; obtaining a first picture number from the first coded picture included in the coded signal; judging if all picture release information is included in the first coded picture, the all picture release information being an instruction to release all pictures stored in the memory; decoding the first coded picture to obtain a first decoded picture, the first decoded picture having the first picture number; and storing the first decoded picture into the memory; wherein in a case where it is judged that the all picture release information is not included in the first coded picture, the following steps are performed: holding the first picture number of the first decoded picture unchanged after said decoding of the first coded picture; and decoding subsequent coded pictures following the first coded picture, the subsequent coded pictures containing continuous picture numbers following the first picture number, wherein in a case where it is judged that the all picture release information is included in the first coded picture and the all picture release information is not picture type information, the following steps are performed: releasing all pictures except for the first decoded picture, which are stored in the memory, after the decoding of the first coded picture, and prohibiting from using, as a reference picture, the all pictures except for the first decoded picture in the decoding of subsequent coded pictures, changing the first picture number of the first decoded picture to a second picture number after said decoding of the first coded picture and after said releasing of the all pictures except for the first decoded picture; and decoding subsequent coded pictures following the first coded picture, the subsequent coded pictures containing continuous picture numbers following the second picture number, and wherein in a case where it is judged that the all picture release information is included in the first coded picture and the all picture release information is picture type information, the following steps are performed: releasing all pictures except for the first decoded picture, which are stored in the memory and prohibiting from using, as a reference picture, the all pictures except for the first decoded picture in the decoding of subsequent coded pictures; and decoding subsequent coded pictures following the first coded picture, the subsequent coded pictures containing continuous picture numbers following the first picture number.