| 摘要 |
A method of communicating video or image data in intra-coded and predicted frames includes generating a sequence of video or image frames, including intra-coded frames interspersed by predicted frames of a video or image stream (690), including a first intra-coded frame. The method includes the steps of transcoding at least one intra-coded frame I<SB>4</SB> subsequent to the first intra-coded frame into at least one predicted intra-coded frame P'<SB>4</SB>, thereby forming a modified sequence of video or image frames, wherein the at least one predicted intra-coded frame is predicted from said first intra-coded frame; and communicating said modified sequence of video or image frames including the at least one predicted intra-coded frame in place of the at least one intra-coded frame from which the at least one predicted intra-coded frame was transcoded. Alternatively a first predicted intra-coded frame may be generated from the first intra-coded frame, and subsequent predicted intra-coded frames generated from previous predicted intra-coded frames (fig 13). In this manner, fewer intra-coded frames are sent over for example, an IP network, thereby saving bandwidth usage over traditional methods, with minimal loss of quality of the video signal. The invention finds particular application in video conferencing. |
