TRANSMISSION DEVICE, TRANSMISSION METHOD, RECEPTION DEVICE, AND RECEPTION METHOD
To improve coding efficiency in encoding and transmitting image data of a base layer and an enhancement layer. The image data of each picture of the base layer is encoded to generate a first coded stream. The image data of each picture of the enhancement layer is encoded to generate a second coded stream. A container including the streams is transmitted. A picture of the base layer can be used as a reference picture in encoding the image data of each picture of the enhancement layer, and conversion processing for causing the image data of the base layer to correspond to the image data of the enhancement layer is applied to a block of the reference picture to perform motion compensation prediction coding processing when the picture of the base layer is used as the reference picture.
1 . A transmission device comprising:
an image coding unit configured to encode image data of each picture of a base layer to generate a first coded stream and encode image data of each picture of an enhancement layer to generate a second coded stream; and
a transmission unit configured to transmit a container including the first coded stream and the second coded stream, wherein
the image coding unit
is able to use a picture of the base layer as a reference picture in encoding the image data of each picture of the enhancement layer, and
applies conversion processing for causing the image data of the base layer to correspond to the image data of the enhancement layer to a block of the reference picture to perform motion compensation prediction coding processing when using the picture of the base layer as the reference picture.
2 . The transmission device according to claim 1 , wherein
the image data of each picture of the enhancement layer includes image data of a picture having different display timing from each picture of the base layer.
3 . The transmission device according to claim 1 , wherein
the image data of the base layer is image data of a first resolution, and the image data of the enhancement layer is image data of a second resolution larger than the first resolution, and
the image coding unit performs, as the conversion processing, scaling processing of changing a resolution of a reference block in the reference picture from the first resolution to the second resolution.
4 . The transmission device according to claim 3 , wherein
the image coding unit further performs, as the conversion processing, shaping processing of correcting a blunt edge of an image, for the scaled image data.
5 . The transmission device according to claim 3 , wherein
the first resolution is an HD resolution, and the second resolution is a UHD resolution.
6 . The transmission device according to claim 5 , wherein
the UHD resolution is a 4K resolution, and
the image coding unit
performs block matching processing using the scaled reference block, for each vector block configured by two-dimensionally adjacent 2×2 four prediction blocks of a picture of the enhancement layer, to determine a first motion vector, and performs block matching processing with each of the four prediction blocks in the scaled reference block to determine a second motion vector corresponding to each of the prediction blocks, and performs the motion compensation prediction coding processing.
7 . The transmission device according to claim 1 , wherein
the image data of the base layer is image data of a first dynamic range, and the image data of the enhancement layer is image data of a second dynamic range wider than the first dynamic range, and
the image coding unit performs, as the conversion processing, processing of converting a pixel value of the block of the reference picture to correspond to a pixel value of the second dynamic range.
8 . A transmission method comprising:
an image coding step of, by an image coding unit, encoding image data of each picture of a base layer to generate a first coded stream, and encoding image data of each picture of an enhancement layer to generate a second coded stream; and
a transmission step of, by a transmission unit, transmitting a container including the first coded stream and the second coded stream, wherein,
in the image coding step,
a picture of the base layer is able to be used as a reference picture in encoding the image data of each picture of the enhancement layer, and
conversion processing for causing the image data of the base layer to correspond to the image data of the enhancement layer is applied to a block of the reference picture to perform motion compensation prediction coding processing when the picture of the base layer is used as the reference picture.
9 . A reception device comprising:
a reception unit configured to receive a container including a first coded stream obtained by encoding image data of each picture of a base layer and a second coded stream obtained by encoding image data of each picture of an enhancement layer, wherein
a picture of the base layer is able to be used as a reference picture in encoding the image data of each picture of the enhancement layer, and conversion processing for causing the image data of the base layer to correspond to the image data of the enhancement layer is applied to a block of the reference picture to perform motion compensation prediction coding processing when the picture of the base layer is used as the reference picture, and
the reception device further comprises
a processing unit configured to process the first coded stream, or the first coded stream and the second coded stream, according to display capability, to obtain display image data.
10 . A reception method comprising:
a reception step of, by a reception unit, receiving a container including a first coded stream obtained by encoding image data of each picture of a base layer and a second coded stream obtained by encoding image data of each picture of an enhancement layer, wherein
a picture of the base layer is able to be used as a reference picture in encoding the image data of each picture of the enhancement layer, and conversion processing for causing the image data of the base layer to correspond to the image data of the enhancement layer is applied to a block of the reference picture to perform motion compensation prediction coding processing when the picture of the base layer is used as the reference picture, and
the reception method further comprises
a processing step of, by a processing unit, processing the first coded stream, or the first coded stream and the second coded stream, according to display capability, to obtain display image data.