Multi-component picture or video coding concept
The coding efficiency of a multi-component picture or video coding concept is improved by reconstructing a third component signal relating to a third component of the multi-component video using inter-component prediction from both a reconstructed first component signal and a reconstructed second component signal.
1 . A decoder, comprising:
a processor configured to execute a program for decoding a multi-component video based on operations including:
reconstructing a first component signal relating to a first component of the multi-component video from a data stream;
reconstructing a second component signal relating to a second component of the multi-component picture video from the data stream; and
reconstructing a third component signal relating to a third component of the multi-component video using inter-component prediction (ICP) based on ICP information, the reconstructed first component signal and the reconstructed second component signal.
2 . The decoder according to claim 1 , the operations further including determining weights based on the ICP information, wherein the weights indicate contributions of the reconstructed first component signal and the reconstructed second component signal to the inter-component prediction.
3 . The decoder according to claim 2 , wherein the data stream includes the ICP information.
4 . The decoder according to claim 2 , wherein at least one of the weights is entropy-decoded based on context modeling and is represented by a sign value and an absolute value.
5 . The decoder according to claim 4 , wherein the absolute value is entropy decoded using context-modeling based on the sign value, and the sign value is decoded before the absolute value.
6 . The decoder according to claim 1 , wherein the decoder is configured to be responsive to a multiple-source ICP signalization in the data stream to switch, for different ICP mode portions of the multi-component video, between ICP coding modes of a set of ICP coding modes, which includes:
(a) a multiple-source ICP coding mode in which the decoder is configured to reconstruct the third component signal in a current sub-portion of a current picture of the multi-component video using inter-component prediction from a signaled one of, or a combination of, spatially corresponding portions of the reconstructed first component signal and the reconstructed second component signal,
(b) at least one of a non-ICP coding mode in which the decoder is configured to reconstruct the third component signal in a current sub-portion of the current picture of the multi-component video without using any inter-component prediction, and
(c) a fixed-one-source ICP coding mode in which the decoder is configured to reconstruct the third component signal in the current sub-portion of the current picture of the multi-component video using inter-component prediction from spatially corresponding portions of a fixed one of the reconstructed first component signal and the reconstructed second component signal, which is fixed within each portion of the multi-component video for which the decoder, in response to the multiple-source ICP signalization, switches to the fixed-one-source ICP coding mode.
7 . The decoder according to claim 6 , wherein the multiple-source ICP signalization is signaled in the data stream such that the ICP mode portions are single pictures, picture sequences or slices.
8 . The decoder according to claim 1 , wherein the first component is a luma component, the second component is a first chroma component, and the third component is a second chroma component.
9 . The decoder according to claim 1 , wherein the decoder is configured to switch, at a first sub-picture granularity, between reconstructing the third component signal in a current picture of the multi-component video using inter-component prediction from a spatially corresponding portion of the reconstructed first component signal, and reconstructing the third component signal in the current picture of the multi-component video using inter-component prediction from a spatially corresponding portion of the reconstructed second component signal.
10 . An encoder, comprising:
a processor configured to execute a program for encoding a multi-component video based on operations including:
encoding a first component signal relating to a first component of the multi-component video into a data stream;
encoding a second component signal relating to a second component of the multi-component video into the data stream; and
encoding a third component signal relating to a third component of the multi-component video using inter-component prediction (ICP) based on ICP information, the first component signal and the second component signal.
11 . The encoder according to claim 10 , the operations further including determining weights based on the ICP information, wherein the weights indicate contributions of the first component signal and the second component signal to the inter-component prediction.
12 . The encoder according to claim 11 , wherein the operations further include inserting the ICP information into the data stream.
13 . The encoder according to claim 11 , wherein at least one of the weights is entropy-encoded based on context modeling and is represented by a sign value and an absolute value.
14 . The encoder according to claim 13 , wherein the absolute value is entropy encoded using context-modeling based on the sign value, and the sign value is encoded before the absolute value.
15 . The encoder according to claim 10 , wherein the first component is a luma component, the second component is a first chroma component, and the third component is a second chroma component.