Layered decomposition of chroma components in EDR video coding
AssigneeDolby Laboratories Licensing Corporation
InventorsGuan-Ming Su, Qian Chen, Sheng Qu
Life of this patent
Estimating the term…
Abstract
An encoder receives one or more input pictures of enhanced dynamic range (EDR) to be encoded in a coded bit stream comprising a base layer and one or more enhancement layers. To encode the chroma pixels, the encoder generates a luma mask and a corresponding chroma mask. Based on generated high-clipping and low-clipping thresholds, the encoder determines the appropriate parameters to encode the chroma values in the base and enhancement layers.
Claims13
A method to encode chroma pixel values of an input picture of enhanced dynamic range (EDR) with a layered encoder, the method comprising:
- generating a luma mask, the luma mask indicating a selection of luminance pixel values in the input picture to be clipped in a base layer (BL) by the encoder;
- generating an initial chroma mask based on the luma mask;
- searching to determine a high-clipping threshold based on the chroma pixels values of pixels defined by the initial chroma mask and a first search criterion;
- if the high-clipping threshold is determined, then coding the chroma pixel values that are higher than the high-clipping threshold in an enhancement layer (EL) signal, otherwise searching to determine a low-clipping threshold based on the chroma pixels values of the pixels defined by the initial chroma mask and a second search criterion;
- and
- if the low-clipping threshold is determined, then coding the chroma pixel values that are lower than the low-clipping threshold in the enhancement layer (EL) signal.
An apparatus to encode chroma pixel values of an input picture of enhanced dynamic range (EDR) with a layered encoder, the apparatus comprising:
- an input to receive an input image comprising pixel values;
- and
- a processor configured to execute instructions to:
- generate a luma mask, the luma mask indicating a selection of luminance pixel values in the input picture to be clipped in a base layer (BL) by the layered encoder;
- generate an initial chroma mask based on the luma mask;
- search to determine a high-clipping threshold based on chroma pixels values of pixels defined by the initial chroma mask and a first search criterion;
- if the high-clipping threshold is determined, then coding the chroma pixel values that are higher than the high-clipping threshold in an enhancement layer (EL) signal, otherwise searching to determine a low-clipping threshold based on the chroma pixels values of the pixels defined by the initial chroma mask and a second search criterion;
- and
- if the low-clipping threshold is determined, then coding the chroma pixel values that are lower than the low-clipping threshold in the enhancement layer (EL) signal.
Dependencies are inferred from the claim text.