A data converting apparatus includes a video encode or decode operation unit which decodes a bit stream into a video signal; an IO buffer into which the bit stream transferred from an encoded-video recorder is stored; and a DMAC which controls a process of determining, in accordance with free space of the IO buffer and an OP buffer, either a first path going through a main memory or a second path bypassing the main memory as the transfer path, and having the bit stream, that is stored in the IO buffer, inputted into the video encode or decode operation unit via the determined transfer path.