According to one embodiment, an information processing apparatus includes an inter-prediction unit which generates a prediction signal, a transformation unit which orthogonal transform a prediction residual signal between the prediction signal and a picture signal of the macro block, and an inter-prediction mode determining unit which determines a combination of an inter-prediction mode used by the inter-prediction unit and DCT used by the transformation unit for each macro block. The inter-prediction mode determining unit includes a first selection unit which selects a preset number of inter-prediction modes from plural types of inter-prediction mode with a specified type of DCT, and a second selection unit which selects a combination of one inter-prediction mode and one DCT from the preset number of inter-prediction modes selected by the first selection unit and the plural types of DCT.