The present disclosure relates to a file generation device and a method, and a content playback device, enabling efficient access to arbitrary subsamples within a sample. As indicated by grouping_type=‘sgss’, a subsample sample group (entry) structure is used as an sgpd. mha1 is identification information indicating 3d audio. As indicated by entry_count=3, the sgpd includes three entries. The three entries are defined to be mha1 0, mha1 1, and mha1 2. To assign these meanings of the sgpd to levels, the sgpd entries are linked to leva entries in index order. The present disclosure may be applied to a content playback system equipped with a content server and a content playback device, for example.