Transcoding in the block DCT space

Transcoding enables the transformation of multimedia content to adapt to a diverse nature of client/user requirements. In this paper, we propose a technique for transcoding wavelet coefficients to block DCT coefficients in the transform domain. In the first step, the wavelet coefficients are transformed into upsampled block DCT coefficients. Subsequently these transformed coefficients are synthesized by filtering in the block DCT space. To reduce the transcoding complexity, we perform upsampling and filtering operations in a single combined step. The proposed transcoding approach restricts all operations of the synthesis process in the block DCT space. The proposed approach achieves the same quality of reconstruction (Except rounding errors in processing) as that of spatial domain technique with reduced complexity for a given wavelet synthesis filter bank.