Patent ID: 9185436
Filing Date: 2015-11-10
Classification: H04N

Abstract:
1. A method for determining coding parameters of a variable-resolution video stream by a video coder, said variable-resolution video stream comprising a plurality of resolution layers and being compressed to be transmitted at a plurality of given data bit rates or a plurality of given qualities through a heterogeneous network to a plurality of users, the method comprising: generating reference charts with which to determine compression parameters, at least a quantization step, and/or protection parameters, at least a protection efficiency, as a function of a data bit rate and of a perceived quality; initializing parameters representative of said video coder, at least a maximum number C determining, for each user associated with a transmission link having an available bit rate d retaining, for each user, a resolution C excluding from said representation users whose perceived quality value is below the minimum acceptable quality D evaluating a function f which links the data bit rate to the total bit rate based on the representation of said users; if the function f is strictly increasing for all users considered, then ranking the users in homogeneous groups according to the perceived quality, the users of one and the same group are associated with the same resolution C if the function f is not strictly increasing for at least two consecutive users, executing at least one of the following steps: determining, for each resolution layer of index i and in ascending order of a resolution level, compression parameters, at least a quantization step, and protection parameters, at least an efficiency of a correcting code, based on the reference charts, the quantization step being determined relative to a lowest available bit rate among the transmission links of a group of users to which said resolution layer of index i is assigned, the efficiency of the correcting code being determined as being a lowest efficiency among those allocated to the users of said group; compressing said video stream by applying said determined compression parameters; and protecting said video stream by applying said protection parameters to it.