HYBRID ERROR CONCEALMENT METHOD

Abstract

Disclosed herein is a hybrid error concealment method. The hybrid error concealment method of the present invention includes a first step of calculating a side match distortion, measured when a motion vector for an arbitrary intra-frame is assumed to be zero, and the intra-frame is temporally reconstructed, a second step of applying temporal error concealment when the side match distortion, calculated at the first step, is less than a predetermined low threshold value, a third step of applying spatial error concealment when the side match distortion, calculated at the first step, is greater than a predetermined high threshold value, and a fourth step of performing error concealment based on {circumflex over (m)}{circumflex over (b)}(x,y)=α·{circumflex over (m)}{circumflex over (b)}t(x,y)+β·{circumflex over (m)}{circumflex over (b)}s(x,y) when the side match distortion, calculated at the first step, exists between the low threshold value and the high threshold value. According to the present invention, the hybrid error concealment method improves PSNR performance compared to a conventional spatial error concealment algorithm used in H.264, and obtains greatly improved performance characteristics, particularly when motion is small and the value of a quantization parameter is relatively low.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an example of an H.264 video transmission procedure in a Real-Time Transport Protocol (RTP)/User Datagram Protocol (UDP)/Internet Protocol (IP) environment;

FIG. 2 illustrates an example of an error concealment algorithm for intra-frames based on a weighted pixel averaging method; and

FIG. 3 illustrates an example of an error concealment algorithm for inter-frames based on a Boundary Matching Algorithm (BMA).

Claims

1. A hybrid error concealment method for real-time video transmission in a network environment, comprising: a first step of calculating a side match distortion, measured when a motion vector for an arbitrary intra-frame is assumed to be zero, and the intra-frame is temporally reconstructed;a second step of applying temporal error concealment when the side match distortion, calculated at the first step, is less than a predetermined low threshold value;a third step of applying spatial error concealment when the side match distortion, calculated at the first step, is greater than a predetermined high threshold value; anda fourth step of performing error concealment based on {circumflex over (m)}{circumflex over (b)}(x,y)=α·{circumflex over (m)}{circumflex over (b)}t(x,y)+β·{circumflex over (m)}{circumflex over (b)}s(x,y) when the side match distortion, calculated at the first step, exists between the low threshold value and the high threshold value.

2. The hybrid error concealment method according to claim 1, wherein, at the fourth step, α is a weight for a macroblock obtained through temporal error concealment, and β is a value obtained by subtracting α from 1.

3. The hybrid error concealment method according to claim 1, wherein the temporal error concealment used at the second step employs a temporal error concealment algorithm applied to intra-frames.

4. The hybrid error concealment method according to claim 1, wherein the spatial error concealment used at the third step employs a spatial error concealment algorithm used in H.264 standard.

5. The hybrid error concealment method according to claim 1, wherein the side match distortion calculated at the first step is obtained by calculating side match distortions DUP, DLO, DLE, and DRI, which are measured in upper, lower, left and right locations, respectively, through the following equation, and by obtaining the sum of the side match distortions measured in respective locations: