Video steganography has the advantage of large embedding capacity

but the security is usually neglected when obtain the capacity.In order to balance the two aspects

a secure steganographic algorithm for embedding secret information in compressed video is proposed utilizing the principle of steganography based on error-correcting code.The strategy of two-time embedding is designed to embed secret bits.In other words

the secret bits are firstly embedded into the error-correcting codeword.Then by modifying the level value of run-level pair corresponding to the DCT coefficient which is not differentially encoded

the stego error-correcting codeword obtained by first-time embedding is secondly embedded.At the same time

measures are taken for the purpose of preserving video stream size.Experimental results show that the algorithm has a good visual and statistical imperceptibility

and satisfies the Kerchhoff rule in cryptography.Furthermore

the algorithm has a considerable embedding capacity

and can keep the nearly invariant size of video stream.