SEGA SATURN DEVELOPER'S MANUAL

4. Overview of stream access
4.1 Streams and stream groups
(1) Stream: A group of sectors that have the same subheader (FN, CN, SM, CI) and are basically processed in the same way is called a stream. It does not have to be physically contiguous sectors.
(2) Stream group: By interleaving and recording multiple streams like audio and video, you can access related streams in synchronization. A set of related streams is called a stream group.
4.2 Stream range: Stream range is specified in the following two ways.
(1) Stream open by file: A stream can be opened by specifying a file identifier (STM_OpenFid). In this case, the range of the stream is from the start frame address to the end frame address of the file.
The end frame address is actually calculated from the start frame address and the total number of sectors in the file. In the case of interleaved files, it is calculated as recorded with a fixed interleave factor (fixed interleave).
(2) Open stream by directly specifying the frame address range: Users can open a stream by directly specifying the frame address range of the stream (STM_OpenFrange). In this case, the specified range becomes the stream range as it is.
The frame address range specifies the top frame address and the number of physical sectors.

4. Overview of stream access