The RealMagic adapter enables hardware-assisted playback of MPEG files. MPEG video content is contained in an MPEG-specific file format. This file format, like AVI, interleaves audio and video data but is quite different from the tagged AVI format and requires a unique IOProc. The MPEG IOProc performs the file-format processing in the hardware-assisted environment, while decompression of both audio and video is performed by the hardware.
The digital video device provides normal-speed playback support (in the forward direction only) of MPEG files. The common file extension for MPEG files is .MPG. Seeking is supported, however seeking is an approximation to the nearest MPEG picture group. The size of a picture group is movie-dependent but is commonly 8 frames, so seeking takes place to within one-third of a second, in most cases.