Digital audio watermarking method and apparatus using a color image as a watermark

A color image of relatively large size is inserted in audio signal data as a watermark. And yet the watermark embedded audio signal data can be played back with sound quality very close to that of original audio signal data. The original audio signal data are reshaped into a matrix form to correspond to that of a color image file before wavelet transformed while the color image file undergoes a format conversion before discrete cosine transformed. The coefficients of the transformed audio signal data and the reformatted color image are combined before inverse-matrix-reshaped and subsequently inverse-wavelet-transformed to finally generate an audio signal wherein a color-image watermark has been inserted.