Replacement of frame data in a video stream signal

Abstract

Provided is an apparatus and a method for replacing a video stream signal. The video stream signal represents a succession of frames, comprising a plurality of dependent frames that each provide for prediction of visual content using selectable ones of a preceding and following anchor frame that precede and follow the plurality of frames respectively. When a shortage of transmission bandwidth occurs, the apparatus generates a processed version of the video stream signal wherein a bit-rate alteration is performed starting from one of the dependent frames before an end of said plurality. Said alteration is executed by substituting a standard prediction from the following anchor frame at least for data in the video stream signal that encodes a region in said one of the dependent frames. The bit rate alteration is accompanied by a switch to a mode in which the processing circuit substitutes a standard prediction from the following anchor frame in all following dependent frames that follow said one of the dependent frames until the following anchor frame, for data in the video stream signal that encodes the region in said following dependent frames. In an embodiment interlacing is killed for the replaced regions.

Description

technical field [0001] The present invention relates to devices and methods for processing video stream signals. Background technique [0002] It is known from WO2005 / 065030 that the bit rate of an MPEG video stream signal can be reduced by replacing selected B-frames with "empty" frames, each representing an adjacent anchor frame (I frame or P frame). US5956088 describes a similar technique. Thus, a reduced quality video stream is achieved with non-zero motion vectors and residual data that requires less data than the original video stream with non-empty B-frames. In an embodiment of WO2005 / 065030 it is described how only selected parts of B-frames with low-motion are blanked, which results in higher quality video at the expense of less data simplification. [0003] It has been found that this technique can cause interference artifacts when applied to interlaced video, ie when each frame contains multiple fields. Furthermore, it has been found that this technique is dif...

AI Technical Summary

Problems solved by technology

This document considers adding slow-moving frames and removing fast-playing frames, but does not replace frames to reduce bitrate

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