Reversible Audio Information Hiding Based on Integer DCT Coefficients with Adaptive Hiding Locations

This paper presents a reversible audio information hiding method based on integer Discrete Cosine Transform (intDCT), and investigates the effectiveness of adaptive hiding locations. In this work, audio data is first divided into several frames with a fixed length, and then, each frame data is transformed into the DCT coefficients by integer DCT in a lossless manner. Then the DCT coefficients are divided by several segments. We extend DCT coefficients out of selected segments to reserve hiding space. In our previous work, the payload was embedded to higher DCT coefficients. While in this paper, we focus on solving the problems to reduce the distortion caused by embedding, as well as to make hiding positions more difficult to be speculated. We examine the adaptive embedding locations by estimating distortion. By experimental evaluation of stego data, the proposed adaptive hiding shows slightly better performance in a segmental SNR (segSNR) criterion, while Listening Quality Objective Mean Opinion (MOSLQO), which is one of the well-used objective criterion for speech quality, degrades, which implies the necessity of the overlapping frame analysis to audio data for improving the sound quality. Spectrum of stego data shows that it is difficult to detect the hiding locations by the proposed method.