US 8,559,501 B2Granted

Method and apparatus for adaptively determining a bit budget for encoding video pictures

AssigneeThomson Licensing

InventorsQu Qing Chen, Zhi Bo Chen, Xiao Dong Gu

Life of this patent

Estimating the term…

Loading patent…

Abstract

When for video coding Intra refresh is used, which inserts Intra coded blocks into previously Inter coded pictures, an efficiently adapted rate control method is required for error resilient video coding. A method for adaptively determining a bit budget for encoding video pictures comprises pre-analyzing each of the pictures of a group of pictures, wherein a relative complexity index is calculated for each picture, allocating bits to the pictures based on their relative complexity index and encoding each of the pictures with the allocated number of bits. The pre-analysis comprises selecting pictures for Intra refresh coding, extracting attention area information from the selected pictures, encoding at least the macroblocks of the attention area using Intra mode, calculating for each picture a complexity index, and calculating from the complexity indices of the pictures of the group a relative complexity index for each picture. Thus, a subjectively better video quality is achieved.

Claims15

Dependent claims

A method for adaptively determining a bit budget for encoding of video pictures, comprising the steps of

selecting a group of at least three adjacent pictures and a bit budget for the selected group of pictures;
pre-analyzing each of the pictures, wherein respective predicted residuals in the frequency domain are generated;
based on the result of the pre-analysis, allocating bits to the pictures;
and
encoding each of the pictures with the allocated number of bits,
wherein the step of pre-analyzing comprises the steps of
extracting attention area information on block or macroblock level for each of the pictures that shall use Intra refresh, wherein Intra refresh means forced intra coding of specified picture portions;
based on said extracted attention area information, generating for each selected picture an Intra refresh map indicating for blocks or macroblocks whether they will be Inter or Intra coded;
generating for each picture a predicted residual according to the Intra refresh map;
transforming the residuals into the frequency domain;
calculating for each of the pictures a complexity index in the frequency domain;
calculating a complexity proportion of each picture based on the complexity indices;
and
allocating to each picture an amount of bits according to its complexity proportion and the bit budget of the group of pictures.

11 more elements

An apparatus for adaptively determining a bit budget for encoding of video pictures, comprising

an extractor for selecting a group of at least three adjacent pictures and selecting a bit budget for the selected group of pictures;
a pre-analysis module for pre-analyzing each of the pictures, wherein respective predicted residuals in the frequency domain are generated;
and
an encoder for encoding each of the pictures with the allocated number of bits,
wherein the pre-analyzer means comprises
an extractor module for extracting attention area information on block or macroblock level for each of the pictures that shall use Intra refresh, wherein Intra refresh has the meaning of forced intra coding of specified picture portions;
an Intra refresh controller for generating at least for each selected picture an Intra refresh map based on said extracted attention area information, the Intra refresh map indicating for blocks or macroblocks whether they will be Inter or Intra coded;
a predictor for generating for each picture a predicted residual according to the Intra refresh map;
a transformer for transforming the residuals into the frequency domain;
a frequency domain analyzer for calculating for each of the pictures a complexity index in the frequency domain and calculating a complexity proportion of each picture based on the complexity indices;
and
a bit allocator for allocating to each picture an amount of bits according to its complexity proportion and the bit budget of the group of pictures.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/308,136Filed 9 Jun 2006
Published: US 2009/0279603 A112 Nov 2009
Granted: 15 Oct 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification16 codes

H04N 19/194
The adaptation method, adaptation tool or adaptation type being iterative or recursive: involving only two passes
H04N 19/103
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: selection of coding mode or of prediction mode
H04N 19/107
Selection of coding mode or of prediction mode: between spatial and temporal predictive coding, e.g. picture refresh
H04N 19/115
Characterised by the element, parameter or selection affected or controlled by the adaptive coding: selection of the code volume for a coding unit…