HF_RUNTIME_FIX_RECEIPT_6.md

HF Runtime Fix Receipt 6 — PATCHED8 Preview Rehydration

Status

HELD for preview-repair packet generation.

Fault observed

The app route processed the video and generated trace receipts, but both top video preview panes showed blank/NaN preview behavior in the Gradio UI.

Cause class

Gradio Video upload/preview behavior was unreliable for this Space runtime even though the uploaded video was readable by OpenCV and the route completed.

Patch applied

• Replaced the left upload gr.Video control with a gr.File video uploader so file intake is stable and path-bound.
• Added coerce_uploaded_path() to support Gradio file/video payload variants.
• Added make_preview_mp4() to create a browser-stable MP4 preview without mutating the canonical source video.
• Added upload-time preview rehydration via video_input.change(...).
• Returned the browser-safe preview MP4 after route execution instead of returning the raw uploaded path.
• Kept source hashing, atomization, frame extraction, scene detection, trace-stack construction, receipt generation, and packet creation intact.

Boundary preserved

The preview MP4 is a display artifact only. The canonical source remains the uploaded video hash and source capsule authority.

Expected result

After upload, the right preview pane should populate with a playable browser-safe MP4. After route execution, the same preview pane should remain populated while receipts/tables/gallery are generated.