Interdigital Vc Holdings, Inc.

Thomson Licensing

Thomson-csf

Interdigital Ce Patent Holdings, Sas

Interdigital Madison Patent Holdings, Sas

Thomson Licensing S.a.

Christophe Chevance

Edouard Francois

Franck Hiron

Dominique Thoreau

Pierre Andrivon

Philippe De Lagrange

Vincent Bottreau

Philippe Bordes

Fabrice Urban

Jurgen Stauder

Christel Chamaret

Patrick Morvan

Erik Reinhard

Philippe Salmon

Thierry Viellard

Pierre Ruellou

Alain Ferre

Julien Haddad

Joaquin Zepeda Salvatierra

Jérome Vieron

Edouard Fran&ccedil;ois

Jéróme Vieron

Xavier Castellan

Jean Quignon

Francois Edouard

A method for encoding a block of a picture comprising, for at least one sample of the block and for one current component: obtaining a prediction value; determining a mapped residual value from a source value of the sample and from the prediction value responsive to a mapping function; and encoding the mapped residual value into a bitstream; wherein the mapping function is derived to obtain at least one of a reduction of a bit cost of the bitstream for a given quality of reconstruction or an increase of quality of reconstruction for a given bit cost of the bitstream.

Method and device for predictive picture encoding and decoding

Described are systems and methods for encoding or decoding a picture part of video information can include using a refinement mode per block where the refinement mode can be based on a refinement parameter. The refinement mode can include a cross-component refinement that can be a cross-component chroma refinement. The refinement mode can include enabling selection per block of a refinement parameter where the refinement parameter can include one or more chroma refinement parameters included in a chroma refinement table.

Refinement mode processing in video encoding and decoding

A method for reconstructing a block of an image, said block comprising a plurality of components and being predictively encoded from a reference block, includes if a single quantized residual block is used to jointly encode at least two components of the plurality of components, deriving at least one quantization matrix from a plurality of scaling lists each defined for one component of the plurality of components; and, applying one of the at least one derived quantization matrix to the single quantized residual block to obtain a reconstructed residual block for each of the at least two components.

Derivation of quantization matrices for joint Cb-Br coding

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.

Luma to chroma quantization parameter table signaling

A method and apparatus for performing a forward mapping function or its inverse is implemented through information conveyed in a bitstream to perform mapping. The information can be implemented in a uniform or non-uniform lookup table. A decoder can receive the information and derive the inverse function to be used. In one embodiment, a decoder receives information representative of an inverse mapping function and uses the information to implement an inverse mapping lookup table for intra coded picture portions and can derive a forward mapping lookup table to be used with an inverse mapping lookup table for inter coded picture portions.

In-loop reshaping adaptive reshaper direction

Methods and apparatus provide mapping functions for video encoding or decoding by replacing a pivot point of a uniformly sampled inverse mapping function by another pivot point not located on an original non-uniformly sampled inverse mapping function. In one embodiment a last pivot point of the inverse mapping function is extended based on a previous slope whose curve is plotted between two previous pivot points or based on the preservation of the slope which is dual to the existing slope of the equivalent section in the forward mapping function. Syntax is provided that assists the mapping and inverse mapping and clipping.

Luma mapping with chroma scaling (LMCS) lut extension and clipping

An encoding method for a picture part encoded in a bitstream and reconstructed can involve refinement data encoded in the bitstream and determined based on at least one comparison of a version of a rate distortion cost computed using a data coding cost, a distortion between an original version of the picture part and a reconstructed picture part, and at least one other version involving one or more combinations of with or without a refinement by the refinement data, or a refinement either in or out of the decoding loop, or with or without a mapping or an inverse mapping.

Encoding and decoding with refinement of the reconstructed picture

Reshaping can be used to better exploit the sample value distribution of video data. When reshaping is used inside the coding loop, forward mapping is applied to prediction signals from intra or inter prediction, and inverse mapping is applied to reconstructed signals. To simplify the inverse mapping operations, in one embodiment, the inverse mapping function is modelled as a piece-wise linear function, and each line segment is defined on an equi-distant interval of a length equal to a power of 2. In this embodiment, the inverse mapping function is specified by the number of pieces, initial offset value and the slope for each piece. In one example, the slope parameters can be signaled directly in the bitstream. In another example, an initial estimate of the slope parameters can be obtained from the forward mapping function, and the difference between the initial estimate and the actual parameters are signaled.

Inverse mapping simplification

Encoding or decoding a picture part of video information can include using a refinement mode per block where the refinement mode can be based on a refinement parameter. The refinement mode can include a cross-component refinement that can be a cross-component chroma refinement. The refinement mode can include enabling selection per block of a refinement parameter where the refinement parameter can include one or more chroma refinement parameters included in a chroma refinement table.

A method for encoding a block of a picture is disclosed. The method comprises for at least one sample of the block and for one current component: &#x2014;obtaining a prediction value; &#x2014;determining a mapped residual value from a source value of the sample and from the prediction value responsive to a mapping function; and &#x2014;encoding the mapped residual value into a bitstream; wherein the mapping function is derived to obtain at least one of a reduction of a bit cost of the bitstream for a given quality of reconstruction or an increase of quality of reconstruction for a given bit cost of the bitstream.

A method for decoding a block of a picture represented in a current HDR/WCG format is disclosed. The method comprises receiving a bitstream representative of a coded block of picture, an indication representative of a default d QP table (index_d QP_table), an indication representative of a QP offset (slice_qp_delta); determining a quantization parameter responsive to the current format based on the default d QP table and the QP offset; decoding the coded block of a picture using the determined QP. Corresponding encoding method, transmitting method, decoding device, encoding device and transmitting device are disclosed. Besides an embodiment relative to adapting generic codec parameters to any HDR/WCG format as done for d QP table is also disclosed.

Encoding and decoding pictures in of high dynamic range and wide color gamut format

The present principles are directed to a parameterized OETF/EOTF for processing images and video. The present principles provide a method for encoding a picture, comprising: applying a parameterized transfer function to a luminance (L) signal of the picture to determine a resulting V(L) transformed signal; encoding the resulting V(L); wherein the parameterized transfer function is adjusted based on a plurality of parameters to model one of a plurality of transfer functions. The present principles also provide for a method for decoding a digital picture, the method comprising: receiving the digital picture; applying a parameterized transfer function to the digital picture to determine a luminance (L) signal of the digital picture, the parameterized transfer function being based on a plurality of parameters; wherein the parameterized transfer function is adjusted based on a plurality of parameters to model one of a plurality of transfer functions.

Methods, systems and apparatus for electro-optical and opto-electrical conversion of images and video

The present principles relates to a method and device for encoding an input video comprising a luma component and two chroma components. The method comprises: &#x2014;reshaping of said input video by applying () piece-wise linear functions to the luma and chroma components; &#x2014;encoding () the reshaped video into a bitstream; and &#x2014;encoding () parameters representative of said piece-wise linear functions as side information; and the method is characterized in that reshaping of said input video further depends on a targeted range of a decoded reshaped video and the range of a reconstructed video after an inverse-reshaping is applied on the decoded reshaped video.

Method for encoding an input video comprising a luma component and two chroma components, the method comprising reshaping of said input video based on reshaping functions

The invention relates to a method for deriving motion data for a macroblock divided in elementary blocks of a high resolution picture, called high layer macroblock, from motion data of macroblocks of a low resolution picture, called base layer macroblock. The method comprises the following steps:

Method for deriving motion for high resolution pictures from motion data of low resolution pictures and coding and decoding devices implementing said method

A reframing application crops a sub-part of a video source, based on its content. The reframing application involves a visual attention model that produces a saliency map, and a dedicated reframing algorithm that extrapolates a cropping window based on that saliency map. After cropping, only the reframed portion of each video image remains visible. A method for processing images of a video sequence comprises steps of determining parameters of the video sequence, parameters of a previously decoded subsequence of the video sequence and user settings, determining a portion to be cropped according to the determined parameters, and cropping in a reframing step the determined portion for being displayed. An advantage of the invention is that an advanced automatic solution is provided for tuning automatically the reframing parameters, based on the content of a video.

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Brece, France

Christophe Chevance