Patent ID: 11943450
Assignee: DEUTSCHE TELEKOM AG
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for estimating blockiness in a video frame of transform-based video encoding, the method comprising:
obtaining a bitstream of a transform coded video signal, the signal being partitioned into video frames and all operations being performed on a per frame basis, wherein coefficients constituting transforms encoded in the bitstream of the video frames are read;
averaging the coefficients of the transforms encoded in the bitstream into one averaged transform matrix per transform block size i;
generating or making available one weighting matrix per averaged transform of block size i, comprising weighting factors;
computing intermediate weighted average transform matrices by processing each averaged transform matrix with the corresponding weighting matrix;
processing all members of each weighted and averaged transform matrix into a single value per transform of block size i, to obtain intermediate signals Bls[i]; and
computing a single value Bl0 by weighting values of the intermediate signals Bls[i] according to an area in the respective video frame and adding up the weighted values of the intermediate signals Bls[i];
wherein the area is the area which the quantity of the transform matrices of block size i cover per video frame, and wherein this area is dependent on the number of transforms of a specific block size i, NTr[i], in the examined frame and the number of pixels each of these transforms covers, and wherein Bl0 is computed using the formula

Bl0=Bls[4×4]*NTr[4×4]+4*Bls[8×8]*NTr[8×8]+16*Bls[16×16]*NTr[16×16]+ . . . ;

wherein blockiness is further estimated as Bl1 using a factor C(QP) dependent on a frame averaged quantization parameter QP and a codec dependent maximum QP, QP_max, where C(QP) is defined as C=exp (5*((QP_max−QP)/QP_max)); and
wherein Bl1=Bl0*C(QP).