Importing Footage

Beta — research prototype

Xianji is an early-stage research instrument, not a shipping product. The trial engine and its timing are verified; much of the surrounding workflow is not built yet. Tennis is configured but not runnable. See Current Limitations before planning around it.

Before you start

• The output folder is in the iPad’s Files app
• manifest.json and the clips/ folder are together in the same folder

Importing

1. From the home screen, tap Import footage
2. Tap the blue Import footage button
3. The iOS file browser opens, filtered to .json files
4. Select manifest.json

The button reads Importing… while it works. A green Imported N shots card confirms success.

Warnings

Amber warning cards may appear below the confirmation. The import has already been written at this point — if a warning is serious, delete the footage from the Footage screen and fix it at source.

Warning	Meaning	What to do
Viewpoint warning	Footage is not from the receiver position	Serious. Results are not comparable with receiver footage. Consider re-filming
N clip files are missing from disk	The clips/ folder didn’t come with the manifest	Delete, transfer both together, re-import
N contact frames are unconfirmed	Normal for a fresh import	Annotate before running a session
No shots for FL, BC…	Some zones have no examples	The forced choice is narrower than it appears, so accuracy will read artificially high. Add shots for the missing zones
Not marked as consented	No consent recorded on this footage	Record consent for footage of identifiable people

Errors

If the manifest is invalid, a red Error card appears and nothing is imported. See Manifest Format for the full list of causes.

The most common:

• Unsupported manifest schema version — the desktop script and app are different versions
• This video has already been imported — delete the existing copy first
• Zone code not defined — wrong sport’s zone codes in the shot list

The Footage screen

Tap Footage from the home screen to see everything imported. Each card shows the footage id, its frame rate and resolution, and status chips:

Chip	Meaning
Shots: N	Total shots in this set
Needs annotation: N (amber)	Contact frames not yet confirmed
Ready (green)	All shots confirmed — safe to run sessions
Excluded: N	Shots you rejected during annotation
Side-on (red)	Non-receiver viewpoint
No consent recorded (red)	Consent field is false or absent

Tip

Check for the green Ready chip before running any session you intend to record.

Deleting footage

Tap the trash icon on a footage card. The confirmation reads “Delete this footage and every shot from it? Sessions already run are kept.”

Deleting footage does not delete sessions already measured against it — but it does remove the ability to inspect which clips produced them.

Next steps

• Annotating Shots →
• Troubleshooting →