Based on a novel generalized chaotic synchronization system (GCSS), this paper introduces a steganography scheme to secret multimedia information. Firstly a sender uses the chaotic stream generated by the GCSS to mask a secret image and a secrete text according to prescribed rules. Secondly he uses the least significant bit (LSB) embedding method to embed the masked pseudo-liked messages into an unsuspicious video frequency file frame-by-frame for two times. A receiver can use nonsymmetric keys and the GCSS to decrypt the secrete information from the video frequency file and confirm the data origin authentication, without knowing any knowledge of the cover video and communicating with the sender. The key space of the scheme can reach 10 326. The analysis of the key space, sensitivity of key parameters imply that this scheme has good security. The scheme can be applied in the multimedia covert Internet communications