One of STx's strengths lies in its non-destructive coupling of sound and analysis data. This 'metadata' includes
- segment annotations (attributes)
- extracted parameters
- classification based on MPEG-7 (being developed)
Each sound file has, by default, an associated XML metadata file with the name MarriageOfFigaro.wav.stxsm (if the sound file is called MarriageOfFigaro.wav). By default, each time STx starts up, the metadata for each sound file in the current project file is loaded. When STx is then terminated, the metadata is written to disk. This behaviour can be modified (see Importing and Exporting Project Metadata).