A review: Data transmission techniques over the network by using steganography

This review paper is concentrating on two data hiding approaches using compressed MPEG video files. The first approach by modulating the quantization scale[26] of a constant bitrate video, message bits are hided. A payload of one message bit per macroblock is achieved. A second order multivariate regression[26] is used to find an association between macroblock-level feature variables and the values of a hidden message bit. The regression model is then used by the decoder to predict the values of the hidden message bits with very high prediction accuracy. The second approach uses the flexible macroblock ordering feature of H.264/AVC to hide message bits. Macroblocks are assigned to arbitrary slice groups according to the content of the message bits to be hidden. A maximum payload of three message bits per macroblock is achieved.The experimental solutions are analyzed in terms of message extraction accuracy, message payload, excessive bitrate and quality distortion. And also we are reviewing the paper which presents an improved data hiding techniques based on BCH (n,k,t) coding.