File Use Vocabulary
The File Use Vocabulary is a list of subclasses of pcdm:File that describe the role a pcdm:File plays within a pcdm:Object. These classes, combined with technical metadata (mime type, image resolution, etc.), should be used to determine which file to use in a given context.
File Use Values
- Original File: the original file uploaded by the user
- Thumbnail Image: low resolution placeholder image
- Extracted Text: text extracted from documents/OCR
- Preservation Master File: best quality file in a format appropriate for long-term preservation
- Intermediate File: high quality representation of the Object, appropriate for generating derivatives or other additional processing
- Service File: a format generated for serving to users, such as the PDF generated from a Word/LaTeX source file, MP3 generated from a WAV file, JPEG generated from a TIFF, etc.
- Transcript: text representation that can be a substitute or complement for accessibility purposes, such as a transcript, subtitles, or closed captions
Examples
| Object Type | Original File | Preservation Master File | Thumbnail Image | Extracted Text | Transcript | Service File |
|---|---|---|---|---|---|---|
| Audio | Logic source file | WAV | JPEG of album cover, promotional poster, etc. | transcript | MP3 | |
| Document | Word Doc | JPEG of first page | text dump | |||
| Image | Photoshop source file, uncropped/uncorrected TIFF | TIFF image | low-res JPEG | OCR text | med-res JPEG | |
| Video | Premiere source file | full-quality MOV | JPEG of title frame | text-to-speech output | subtitles | 720p MPEG4 |
Using Multiple Types
Multiple types may be appropriate for a single file, such as an image originally created as a medium-resolution JPEG. In that case, you can assign both Original File (because it's the original creation format) and Service File (because it's appropriate for serving to end users).