Patent ID: 8675979

Claim:
A transcoder which converts a first coded stream to at least part of which intra prediction is applied, into a second coded stream to which intra prediction and inter prediction are applied, the transcoder comprising: a decoding unit configured to decode the first coded stream on a per predetermined unit basis to generate decoded image data; an intra prediction direction obtaining unit configured to obtain an intra prediction direction on a per processing unit basis, the intra prediction direction being one of intra prediction directions (i) specified in a coding standard used in the coding of the first coded stream and (ii) actually applied to the first coded stream, the processing unit being a processing unit of the intra prediction in coding of the first coded stream; a coding unit configured to code the decoded image data by applying intra prediction or inter prediction on a per prediction processing unit basis to generate the second coded stream; and a control unit configured to control the coding unit so that the coding unit reuses the intra prediction direction obtained by the intra prediction direction obtaining unit in the decoding of the first coded stream performed by the decoding unit, when the coding unit performs the prediction processing using the intra prediction; and a first cost value generating unit configured to generate a first cost value on the per predetermined unit basis based on decoded information generated in a decoding process performed by the decoding unit and before intra prediction or inter prediction is applied, the first cost value indicating coding efficiency when intra prediction is to be applied, wherein the control unit is further configured to control the coding unit so that the coding unit applies intra prediction or inter prediction according to the first cost value on the per predetermined unit basis when coding the decoded image data.