Batch processing doesnt handle case when representations have been deleted.

[johnhbenetech]

Steps to reproduce:

1. Process the collection using either method.
2. Delete the representations folder
3. Rerun the processing job using the GUI

Result:

• Exif and Hashing job seem to run but extract_features/generate_matches does not run

Desired result:

• processing script should have a way to ensure all previously processed representations are still present

[johnhbenetech]

This also seems to happen in the case where you add additional videos to the collection after a round of processing.

1. Process the collection using either method.
2. Add additional videos to mounted folder (these videos may have a variety of created dates old and new)
3. Rerun the processing job using the GUI

Result:
Job finishes without additional processing as it believes all videos are processed

Desired result:
processing script should have a way to ensure all videos in drive are processes