Picture coding method, picture decoding method, picture coding apparatus, picture decoding apparatus, and program thereof
View Patent ↗A picture coding method of the present invention codes a picture signal and a ratio of a number of luminance pixels and a number of chrominance pixels for the picture signal, and then one coding method out of at least two coding methods is selected depending on the ratio. Next, data related to a picture size is coded in accordance with the selected coding method. The data related to the picture size indicates a size of the picture corresponding to the picture signal or an output area, which is a pixel area to be outputted in decoding in a whole pixel area coded in the picture signal coding.
1. A picture decoding method comprising:
decoding, using a processor, a coded picture signal;
decoding a ratio of a number of luminance pixels to a number of the chrominance pixels for the decoded picture signal;
selecting one decoding method out of at least two decoding methods, the one decoding method being selected based on the ratio; and
decoding data related to a picture size in accordance with the selected decoding method,
wherein the data related to the picture size indicates a size of a picture corresponding to the decoded picture signal, and
wherein, when a ratio of a number of horizontal luminance pixels to a number of horizontal chrominance pixels is M:1, said selecting selects a decoding method where a parameter value of a horizontal size included in the decoded data related to the picture size is multiplied by M, the horizontal luminance pixels and the horizontal chrominance pixels being included in the decoded picture signal.
2. The picture decoding method according to claim 1 , wherein the data related to the picture size indicates an output area in a whole pixel area decoded in said decoding of the coded picture signal, the output area being a pixel area to be outputted in decoding.
3. The picture decoding method according to claim 2 , wherein the data related to the picture size includes a bottom crop value and a right crop value, the bottom crop value showing a number of pixels from a bottom end of the whole pixel area to a bottom end of the output area, the right crop value showing a number of pixels from a right end of the whole pixel area to a right end of the output area.
4. The picture decoding method according to claim 3 , wherein the data related to the picture size further includes a top crop value and a left crop value, the top crop value showing a number of pixels from a top end of the whole pixel area to a top end of the output area, the left crop value showing a number of pixels from a left end of the whole pixel area to a left end of the output area.
5. A picture decoding method comprising:
decoding, using a processor, a coded picture signal;
decoding a ratio of a number of luminance pixels to a number of the chrominance pixels for the decoded picture signal;
selecting one decoding method out of at least two decoding methods, the one decoding method being selected based on the ratio; and
decoding data related to a picture size in accordance with the selected decoding method,
wherein the data related to the picture size indicates a size of a picture corresponding to the decoded picture signal,
wherein, when a ratio of a number of vertical luminance pixels to a number of vertical chrominance pixels is N:1, said selecting selects a decoding method where a parameter value of a vertical size included in the decoded data related to the picture size is multiplied by N, the vertical luminance pixels and the vertical chrominance pixels being included in the decoded picture signal.
6. A picture decoding apparatus comprising:
a picture decoding unit operable to decode a coded picture signal;
a ratio decoding unit operable to decode a ratio of a number of luminance pixels to a number of the chrominance pixels for the decoded picture signal;
a selecting unit operable to select one decoding method out of at least two decoding methods, the one decoding method being selected based on the ratio; and
a data decoding unit operable to decode data related to a picture size in accordance with the selected decoding method,
wherein the data related to the picture size indicates a size of a picture corresponding to the decoded picture signal, and
wherein, when a ratio of a number of horizontal luminance pixels to a number of horizontal chrominance pixels is M:1, said selecting unit selects a decoding method where a parameter value of a horizontal size included in the decoded data related to the picture size is multiplied by M, the horizontal luminance pixels and the horizontal chrominance pixels being included in the decoded picture signal.
7. A non-transitory computer-readable recording medium having a picture decoding program recorded thereon, the picture decoding program causing a computer to execute a method comprising:
decoding a coded picture signal;
decoding a ratio of a number of luminance pixels to a number of chrominance pixels for the decoded picture signal;
selecting one decoding method out of at least two decoding methods, the one decoding method being selected based on the ratio; and
decoding data related to a picture size in accordance with the selected decoding method,
wherein the data related to the picture size indicates a size of a picture corresponding to the decoded picture signal, and
wherein, when a ratio of a number of horizontal luminance pixels to a number of horizontal chrominance pixels is M:1, said selecting selects a decoding method where a parameter value of a horizontal size included in the decoded data related to the picture size is multiplied by M, the horizontal luminance pixels and the horizontal chrominance pixels being included in the decoded picture signal.