US 8,077,775 B2 · System and method of adaptive rate control for a video encoder

Abstract

A method of adaptively adjusting a QP of a video encoder to control output bit rate including estimating the QP based on a complexity of a previous frame and encoding bit rate information of a current frame to provide an estimated QP, determining a threshold value based on a video quality factor, a target bit rate and a complexity of a previous interval of the current frame or the same interval of the previous frame, and if the estimated QP is greater than the threshold value, adaptively adjusting the estimated QP using the threshold value, the target bit rate and the complexity of the previous interval. The method may include adaptively limiting a change of the QP between frame intervals based on a difference between the QP and the threshold value. Complexity information may be based on an average of minimum SAD values.

Claims20

Dependent claims

A rate controller which adaptively adjusts a quantization parameter (QP) to control a bit rate of a video encoder, said rate controller comprising:

a first circuit which calculates an estimated QP based on encoding bit rate information of a current frame and first complexity information of a previous frame;
a second circuit which calculates a threshold value based on a video quality factor, a target bit rate and second complexity information of a previous interval of said current frame or of said previous frame;
a comparator which asserts an adjust signal if said estimated QP is greater than said threshold value;
a third circuit which calculates an adaptive QP when said adjust signal is asserted, wherein said adaptive QP is based on said estimated QP and said threshold value;
and
select logic which provides said adaptive QP as a next QP when said adjust signal is asserted and which otherwise provides said estimated QP as said next QP.

3 more elements

A video system for providing real-time video communications, comprising:

a video encoder which converts video data into compressed video information at a bit rate based on a next quantization parameter (QP), said video encoder providing encoding bit rate information and video complexity information;
and
a rate control system, comprising:
accumulation logic which accumulates said encoding bit rate information and said video complexity information;
and
a rate controller, comprising:
a first circuit which calculates an estimated QP based on said encoding bit rate information of a current frame and said video complexity information of a previous frame;
a second circuit which calculates a threshold value based on a video quality factor, a target bit rate, a target frame rate and said video complexity information of a previous interval of said current frame or of said previous frame;
a comparator which asserts an adjust signal if said estimated QP is greater than said threshold value;
a third circuit which calculates an adaptive QP when said adjust signal is asserted, wherein said adaptive QP is based on said estimated QP, said threshold value, said target bit rate, and said video complexity information of a previous interval of said current frame or of said previous frame;
and
select logic which provides said adaptive QP as a next QP when said adjust signal is asserted and which otherwise provides said estimated QP as said next QP.

9 more elements

Dependencies are inferred from the claim text.

System and method of adaptive rate control for a video encoder

Life of this patent

System and method of adaptive rate control for a video encoder

Life of this patent

Abstract

Claims20