Picture coding and decoding method for random accessing

Claim 3

The picture encoding method as claimed in claim 1 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 4

The picture encoding method as claimed in claim 1 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 5

A picture encoding method comprising the steps of: generating a predicted picture signal using one of: (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the locally decoded signal of the intra-coded first field, taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and encoding said difference signal and a flag indicating whether said encoding is made using only the locally decoded signal of the intra-coded first field or the locally decoded signal of the intra-coded first field of the first group and the locally decoded signal of the field belonging to the second group.

Claim 6

A picture encoding method comprising the steps of: generating a predicted picture signal using one of: (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the locally decoded signal of the intra-coded first field, taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and encoding said difference signal and a flag indicating whether said encoding is made using only the locally decoded signal of the intra-coded first field or the locally decoded signal of the intra-coded first field of the first group and the locally decoded signal of the field belonging to the second group.

Claim 7

The picture encoding method as claimed in claim 4 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 8

The picture encoding method as claimed in claim 4 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 11

The picture decoding method as claimed in claim 7 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 12

The picture decoding method as claimed in claim 7 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 13

A picture decoding method comprising the steps of: decoding a flag indicating whether encoding is made using (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, or (ii) only the locally decoded signal of the intra-coded first field, generating a predicted picture signal using only the locally decoded signal of the intra-coded first field if said flag indicates that said encoding is made using only the locally decoded signal of the intra-coded first field, and adding a signal based on an encoded signal of a second field making up a frame along with said first field to said predicted picture signal for decoding said second field.

Claim 14

A picture decoding method comprising the steps of: decoding a flag indicating whether encoding is made using (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, or (ii) only the locally decoded signal of the intra-coded first field, generating a predicted picture signal using only the locally decoded signal of the intra-coded first field if said flag indicates that said encoding is made using only the locally decoded signal of the intra-coded first field, and adding a signal based on an encoded signal of a second field making up a frame along with said first field to said predicted picture signal for decoding said second field.

Claim 15

The picture decoding method as claimed in claim 10 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 16

The picture decoding method as claimed in claim 10 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 19

The encoding device as claimed in claim 13 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 20

The encoding device as claimed in claim 13 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 21

A picture encoding device comprising: means for generating a predicted picture signal using one of: (i) a local decoded signal of an intra-coded first field of a first group and a local decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the local decoded signal of the intra-coded first field, subtraction means for taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and means for encoding said difference signal and a flag indicating whether said encoding has been made using only the local decoded signal of the intra-coded first field or the local decoded signal of the intra-coded first field of the first group and the local decoded signal of the field belonging to the second group.

Claim 22

A picture encoding device comprising: means for generating a predicted picture signal using one of: (i) a local decoded signal of an intra-coded first field of a first group and a local decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the local decoded signal of the intra-coded first field, subtraction means for taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and means for encoding said difference signal and a flag indicating whether said encoding has been made using only the local decoded signal of the intra-coded first field or the local decoded signal of the intra-coded first field of the first group and the local decoded signal of the field belonging to the second group.

Claim 23

The encoding device as claimed in claim 16 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 24

The encoding device as claimed in claim 16 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 27

The decoding device as claimed in claim 19 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 28

The decoding device as claimed in claim 19 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 29

A picture decoding device comprising: means for decoding a flag indicating whether encoding has been made using (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, or (ii) only the locally decoded signal of the intra-coded first field, means for generating a predicted picture signal using only the locally decoded signal of the intra-coded first field if said flag indicates that said encoding is made using only the locally decoded signal of the intra-coded first field, and means for adding said predicted picture signal and a signal based on an encoded signal of a second field making up a frame along with said first field.

Claim 30

A picture decoding device comprising: means for decoding a flag indicating whether encoding has been made using (i) a locally decoded signal of an intra-coded first field of a first group and a locally decoded signal of a field belonging to a second group which is temporally previous to said first group, or (ii) only the locally decoded signal of the intra-coded first field, means for generating a predicted picture signal using only the locally decoded signal of the intra-coded first field if said flag indicates that said encoding is made using only the locally decoded signal of the intra-coded first field, and means for adding said predicted picture signal and a signal based on an encoded signal of a second field making up a frame along with said first field.

Claim 31

The decoding device as claimed in claim 22 wherein said predicted picture signal and the signal based on said second field are block-based signals each made up of plural pixels.

Claim 32

The decoding device as claimed in claim 22 wherein said first field is a first intra-coded picture in a group of plural pictures and said second field is a first predictive-coded picture in the group of plural pictures.

Claim 33

A bitstream representing a plurality of frames each formed from first and second fields, said bitstream produced by the steps of: generating a predicted picture signal of a second field of a respective frame using only a decoded signal of a first field of the respective frame when the first field of the respective frame is an intra-coded field (I-field) and the second field of the respective frame is a predicted-coded field (P-field), taking a difference between the predicted picture signal and a signal based on the second field of the respective frame for generating a difference signal, and encoding said difference signal.

Claim 34

A bitstream representing a plurality of frames each formed from first and second fields, said bitstream produced by the steps of: generating a predicted picture signal of a second field of a respective frame using only a decoded signal of a first field of the respective frame when the first field of the respective frame is an intra-coded field (I-field) and the second field of the respective frame is a predicted-coded field (P-field), taking a difference between the predicted picture signal and a signal based on the second field of the respective frame for generating a difference signal, and encoding said difference signal.

Claim 35

A bitstream produced by the steps of: generating a predicted picture signal using one of: (i) a local decoded signal of an intra-coded first field of a first group and a local decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the local decoded signal of the intra-coded first field, taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and encoding said difference signal and a flag indicating whether encoding has been made using only the local decoded signal of the intra-coded first field or the local decoded signal of the intra-coded first field of the first group and the local decoded signal of the field belonging to the second group.

Claim 36

A bitstream produced by the steps of: generating a predicted picture signal using one of: (i) a local decoded signal of an intra-coded first field of a first group and a local decoded signal of a field belonging to a second group which is temporally previous to said first group, and (ii) only the local decoded signal of the intra-coded first field, taking a difference between the predicted picture signal and a signal based on a second field making up a frame along with said first field for generating a difference signal, and encoding said difference signal and a flag indicating whether encoding has been made using only the local decoded signal of the intra-coded first field or the local decoded signal of the intra-coded first field of the first group and the local decoded signal of the field belonging to the second group.