Record and reproduction apparatus for reading or writing data during reproducing of stream data

A record and reproduction apparatus includes: a CPU; a memory; a recording medium control unit configured to read out data from a recording medium; a reproduction buffer configured to temporarily store stream data such as an image and an audio out of the data read by the recording medium control unit; a reproduction processing unit configured to decode and reproduce the stream data temporarily stored in the reproduction buffer; and an access control unit configured to control the timing by which the access control unit switches between access to the memory and access to the reproduction buffer so that the reproduction processing does not break off during reproduction of the stream data while supervising the state of the reproduction buffer, and to manage the memory and the recording medium control unit in each transaction.