The present invention relates to data processing apparatuses which improve
the quality of decoded data, such as an image and sound, more. A decoding
section 21 decodes, for example, encoded data obtained by JPEG-encoding
an image, and an encoding section 22 encodes first decoded data obtained
as a result to output re-encoded data. Further, a decoding section 23
decodes the re-encoded data to obtain second decoded data. A
class-classification adaptive processing circuit 24 generates a
prediction tap used for a predetermined prediction calculation with tap
coefficients obtained by learning, from the first decoded data and the
second decoded data, and performs the predetermined prediction
calculation by using the prediction tap and the tap coefficients to
obtain a prediction value corresponding to master data used as a master
in the learning. The present invention can be applied to transfer systems
for encoding images and sound to transfer them.