Moving picture coding method and moving picture decoding method
A moving picture coding apparatus includes a counter unit which counts the number of pictures following an intra coded picture; and a motion estimation unit which compares respectively only reference pictures which are the intra coded picture or the following pictures, selected from among a reference picture Ref 1 , a reference picture Ref 2 and a reference picture Ref 3 stored in memories, with a picture signal, and determines the reference picture whose inter picture differential value is smallest.
1. A moving picture coding method for coding a moving picture,
wherein in said moving picture coding method, a picture is coded by one of an intra picture coding method and an inter picture coding method, and
when a picture is coded by the inter picture coding method, at least one of the following pictures is selected as a reference picture: i) an intra coded picture which is coded by the intra picture coding method; ii) a picture located before the intra coded picture in display order; and iii) a picture located after the intra coded picture in display order,
said moving picture coding method comprises:
specifying the intra coded picture as a specified picture which is used for restricting the selection of the reference picture;
in a case where the intra coded picture is specified as the specified picture in said specifying, for a picture to be coded by the inter picture coding method after the specified picture,
selecting, as the reference picture, at least one of the following pictures including i) the specified picture and ii) a picture which is coded after the specified picture, while prohibiting from selecting, as the reference picture, a picture which has been coded before the specified picture, and
coding information which indicates that the intra coded picture is specified as the specified picture which is used for restricting selection of the reference picture, and
in a case where the intra coded picture is not specified as the specified picture in said specifying, for a picture to be coded by the inter picture coding method after the intra coded picture which is not specified as the specified picture,
selecting, as the reference picture, at least one of the following pictures including i) the intra coded picture which is not specified as the specified picture, ii) a picture located before, in display order, the intra coded picture which is not specified as the specified picture, and iii) a picture located after, in display order, the intra coded picture which is not specified as the specified picture, and
coding information which indicates that the intra coded picture is not specified as the specified picture which is used for restricting selection of the reference picture.
2. The moving picture coding method according to claim 1 , further comprising:
deleting a picture which has been coded before the specified picture and is stored in the memory so as to prohibit from selecting, as the reference picture, the picture which has been coded before the specified picture.
3. A moving picture coding apparatus which codes a moving picture,
wherein in said moving picture coding apparatus, a picture is coded by one of an intra picture coding unit and an inter picture coding unit, and
when a picture is coded by the inter picture coding unit, at least one of the following pictures is selected as a reference picture: i) an intra coded picture which is coded by the intra picture coding unit; ii) a picture located before the intra coded picture in display order; and iii) a picture located after the intra coded picture in display order,
said moving picture coding apparatus comprises:
a specifying unit operable to specify the intra coded picture as a specified picture which is used for restricting selection of the reference picture; and
a coding unit:
operable, in a case where the intra coded picture is specified as the specified picture in said specifying unit, to code information which indicates that the intra coded picture is specified as the specified picture which is used for restricting selection of the reference picture,
wherein, for a picture to be coded by the inter picture coding unit after the specified picture, at least one of the following pictures including i) the specified picture and ii) a picture which is coded after the specified picture is selected as the reference picture, and a picture which has been coded before the specified picture is prohibited from being selected as the reference picture; and
operable, in a case where the intra coded picture is not specified as the specified picture in said specifying unit, to code information which indicates that the intra coded picture is not specified as the specified picture,
wherein, for a picture to be coded by the inter picture coding unit after the intra coded picture which is not specified as the specified picture, at least one of the following pictures is selected as the reference picture: i) the intra coded picture which is not specified as the specified picture, ii) a picture located before, in display order, the intra coded picture which is not specified as the specified picture, and iii) a picture located after, in display order, the intra coded picture which is not specified as the specified picture.