An encryption method based on H.264 video stream

Abstract

The invention discloses an encryption method based on H.264 video streaming. During the H.264 coding, a frame of images is divided into m slices (m is more than or equal to 1), each slice contains n macro blocks (n is more than or equal to 1), each macro block is divided into 16 sub-blocks based on 4*4 as a basic unit: that is, Zm,n,0, Zm,n,1, Zm,n,15, and each sub-block contains 16 DCT coefficients, that is, Zm,n,i ={Cm,n,i, 0, Cm,n,i, 1, Cm,n,i,15} (m is more than or equal to 1, n is more than or equal to 1, i is more than or equal to 0 but less than or equal to 15); a DCT coefficient hierarchical model is established in correspondence to the macro block and then divided into a DC coefficient layer and other 15 AC coefficient layers; sequentially, each frame of image data is distributed with a key, that is, each layer is distributed with a key, if necessary, a plurality of layers share one key; each frame of image data is encrypted and the key sequence pointer resets to scramble layer after layer until the frame is completed. The invention has good safety and high compression ratio.

Description

technical field [0001] The invention belongs to an image transmission encryption method, in particular to an encryption method based on the H.264 video stream of the video coding standard. Background technique [0002] H.264 is a new-generation video coding standard jointly formulated by ITU-T and ISO / IEC, which can provide higher compression performance than H.263 and MPEG-4, and can save 30% to 50% when the image coding quality is the same. % bit rate. The excellent compression performance of the new standard makes it play an important role in various fields such as digital TV broadcasting, video real-time communication, network streaming media delivery, and multimedia short messages, and effectively promotes the rapid development of the multimedia industry. However, the extensiveness and convenience of video storage and transmission also cause some very difficult problems in the open network environment, such as illegal interception, information leakage, data tampering, ...

AI Technical Summary

Problems solved by technology

Its disadvantages are: (1) Since the information in each 4×4 unit is completely preserved, the attacker can use the inter-block correlation (such as edge continuity, color and texture similarity, etc.) to decipher; (2) The shuffling process changes The statistical characteristics of the adjacent block coefficients, and the position of the coefficients have changed greatly, so it has a great impact on the signal-to-noise ratio and compression ratio

The disadvantage is that the block-based video coding structure (such as H.264, MPEG-4, etc.) has a great impact on real-time performance, and it is difficult to perform real-time coding

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