Abstract An inter-frame predictive encoding apparatus divides an input into reference and non-reference frames. For the non-reference frames it derives a prediction error signal representing successive frames of a video signal based on differences between pixel data of each such frame and pixel data of at least one reference frame, and executes intra-frame encoding of the reference fames and the prediction error signal. The prediction error signal is transferred through a spatial filter, prior to intra-frame encoding, in which the degree of filtering is controlled by a control signal, for thereby controlling the high frequency components of the error signal to an appropriate level in accordance with respective requirements for the output data rate from the apparatus and spatial resolution of a finally obtained picture.
An inter-frame predictive encoding apparatus for processing a video signal formed of successive frames of pixel data comprising; means (24, 25) for encoding periodically selected reference frames without inter-frame predictive encoding of said reference frames; means (21, 22, 23) for executing inter-frame prediction processing on respective frames intervening between said reference frames to derive prediction error signals for said respective intervening frames based on differences between pixel data of the intervening frames and pixel data of at least one other frame; spatial filter means (3) for filtering said prediction error signals to reduce frequency components in particular ranges thereof; and filter control means (40, 41, 42, 43) responsive to a filter degree control signal produced by filter degree control means for varying the degree of said filtering and including means for controllably by-passing said spatial filter means in accordance with a level of said filter degree control signal.
Claim 2
Dependent Claim
34 words
Apparatus according to claim 1, wherein said filter degree control signal is preset to a fixed value which is selected to provide a desired output encoded data rate from said inter-frame predictive encoding apparatus.
Claim 3
Dependent Claim
44 words
Apparatus according to claim 1 or 2, wherein said inter-frame prediction processing means (21, 22, 23) provides said prediction error signals for each said intervening frame on the basis of a reference frame preceding and a reference frame succeeding each said respective intervening frame.
Claim 4
Dependent Claim
27 words
Apparatus according to any one of claims 1 to 3 further comprising intra-frame encoding means (4) for encoding both said reference frames and said predictive error signals.