Luma to chroma quantization parameter table signaling
AssigneeInterDigital CE Patent Holdings, SAS
InventorsPhilippe De Lagrange, Edouard Francois, Franck Hiron, Christophe Chevance
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Abstract
Compression technology comprises deriving chroma quantization parameter (Qpc) based on luma Qp using luma-to-chroma Qp mapping table. Such a table may be shared by the encoder and the decoder. However, in some cases, signaling such a table in the data stream instead of having it fixed by a standard may be advantageous. The syntax used to encode, signal and decode this table has a cost in terms of bitrate. The present principles propose to signaling of a luma-to-chroma mapping table in the data stream according to different embodiments.
Claims18
A method comprising:
- decoding a QP information for luma from a data stream;
- obtaining a first luma-to-chroma QP mapping table from the data stream;
- determining a second luma-to-chroma QP mapping table wherein a chroma QP value is an addition between a corresponding chroma QP value in the first luma-to-chroma QP mapping table and a corresponding luma QP value in the first luma-to-chroma QP mapping table;
- and
- decoding a block of an image obtained from the stream using the second luma-to-chroma QP mapping table and the decoded QP information for luma.
A device comprising a processor configured for:
- decoding a QP information for luma from a data stream;
- obtaining a first luma-to-chroma QP mapping table from the data stream;
- determining a second luma-to-chroma QP mapping table wherein a chroma QP value is an addition between a corresponding chroma QP value in the first luma-to-chroma QP mapping table and a corresponding luma QP value in the first luma-to-chroma QP mapping table;
- and
- decoding a block of an image obtained from the stream using the second luma-to-chroma QP mapping table and the decoded QP information for luma.
A method comprising:
- obtaining a first luma-to-chroma QP mapping table;
- determining a second luma-to-chroma QP mapping table wherein the chroma QP value is a difference between a chroma QP value in the first luma-to-chroma QP mapping table and a corresponding luma QP value in the first luma-to-chroma QP mapping table;
- and
- encoding, in a data stream, a block of an image and the second luma-to-chroma QP mapping table.
A device comprising a processor configured for:
- obtaining a first luma-to-chroma QP mapping table;
- determining a second luma-to-chroma QP mapping table wherein the chroma QP value is a difference between a chroma QP value in the first luma-to-chroma QP mapping table and a corresponding luma QP value in the first luma-to-chroma QP mapping table;
- and
- encoding, in a data stream, a block of an image and the second luma-to-chroma QP mapping table.
Dependencies are inferred from the claim text.