Video encoding method, decoding method and device

Abstract

The invention discloses a video coding method which comprises the following steps: A. random access cut-in images in uncoded video sequences are coded by adoption of a first kind of prediction means; B. n images coding sequences of which are after the random access cut-in images are coded according to a fourth kind of prediction means by taking the random access cut-in images as reference images, and n is a presetted positive integer; C. other uncoded images coding sequences of which are after the random access cut-in images are coded by taking the random access cut-in images or/and coded images after the random access cut-in images as reference images. The invention also discloses a video decoding method, an encoder, a decoder and a coding and decoding device. Compared with the prior video random access technology, the proposal of the invention saves higher code rate.

Description

technical field [0001] The invention relates to the field of video signal processing, in particular to a video coding method, a decoding method and a device thereof. Background technique [0002] A good video encoding and decoding method needs to be able to effectively support random access operations on the premise of ensuring the highest possible compression efficiency, that is, when the image address with a random access point is passed to the decoder, the decoder can correctly Decoding the picture with the random access point and the pictures following the picture. At present, the prediction methods for encoding video image sequences can be divided into the following three categories: the first type of prediction method uses the encoded pixel data in the same image to encode the current pixel; the second type of prediction method For, the current image is encoded by using the time sequence, that is, the reference image data whose play or display order is before the curr...

AI Technical Summary

Problems solved by technology

[0009] Although the above-mentioned prior art solves the problem of video random access, it brings a new problem, which is to reduce the coding efficiency

Because according to the method for solving random access in the MPEG-2 or H.264 standard, the prediction direction of the C picture or the B picture following the A picture and the number of optional reference pictures will be subject to certain restrictions, like this It will lead to a reduction in the coding efficiency of this group of C images or B images

Specifically, a group of C pictures after the A picture and before the B picture after the A picture can only be coded in the fourth type of predictive mode, but cannot be encoded in the third type of predictive mode; The first B picture following the A picture can only refer to one picture forward, and the reference pictures of the subsequent B pictures will also be limited in number

For video sequences with many random access points, such as broadcast video sequences requiring an average random access point every 0.5 seconds, the problem of reduced coding efficiency caused by existing video random access methods is even more prominent

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