Regions are the basic elements of editing and composing in Ardour. In most cases, a region represents a single contiguous section of one or more media files. Regions are defined by a fixed set of attributes:
When placed into a playlist, they gain additional attributes:
There are other attributes as well, but they do not define the region. Things to know about regions:
By themselves, regions consume very little in terms of computer's resources. Each region requires a small amount of memory, and represents a rather small amount of CPU work if placed into an active track. So, multiplying regions creation whenever needed should not be much of an issue CPU wise.
Although a region can represent an entire audio file, they are never equivalent to an audio file. Most regions represent just parts of an audio file(s) on disk, and removing a region from a track has nothing to do with removing the audio file(s) from the disk (the Destroy operation, one of Ardour's few destructive operations, can affect this). Changing the length of a region has no effect on the audio file(s) on disk. Splitting and copying regions does not alter the audio file in any way, nor does it create new audio files (only recording, and the Export, Bounce and Reverse operations create new audio files).