Content acquisition device, content transmission device, content transmission/reception system, data structure, control method, control program, and recording medium

A client (11) receives a response message including a Content-Type header, a plurality of movie fragments for each of which a quality type is set independently, and an X-Representation-Id header. When determining that contents are received as a media segment according to the received Content-Type header, the client (11) reproduces the movie fragments while referring to the X-Representation-Id header.