maxwellinked/time-lapse-artifacts-derived

Time-Lapse Artifacts: Derived Access Layer

This repository contains reproducible access derivatives for maxwellinked/time-lapse-artifacts. The archival masters remain in the source dataset and remain authoritative.

Related interfaces

• Public browser (pinned snapshot)
• Browser source and revision history

The browser is a static presentation layer and may lag the current Hugging Face dataset. Hugging Face remains authoritative for media, record identities, and machine-readable metadata.

This construction release is deliberately narrower than a benchmark. Its first purpose is to test whether a deterministic pipeline can make the visual record inspectable without collapsing encoded process into a static endpoint or claiming that encoded playback is real drawing time.

Authority boundary

The repository keeps five kinds of information separate:

1. Source identity and curator-verified facts
2. Explicitly unresolved states
3. Deterministic derivatives and measurements
4. Human interpretations
5. Machine interpretations

Only the first three are in scope for the initial pilot. Model captions, embeddings, style labels, quality judgments, and benchmark claims are out of scope.

Initial outputs

For each processed record_id, the pipeline creates:

• a silent H.264 access proxy fitted within 1280 × 1280 pixels
• 21 JPEG frames sampled at normalized encoded positions from 0.00 to 1.00
• exact SHA-256 hashes and deterministic 64-bit difference hashes for frames
• adjacent-frame Hamming distances, reported as measurements rather than interpreted as meaningful or meaningless change
• a JSON derivation manifest pinned to the source repository revision, published Xet identity, Hub LFS SHA-256, and independently computed download SHA-256

Normalized encoded position is not real drawing time. The final sampled frame is an encoded endpoint, not a claim that the complete process was captured.

Pipeline validation set

data/pipeline_validation_set.csv is an engineering test fixture, not a representative sample. Records are selected by declared rules designed to expose pipeline failures: duration and file-size extremes, median cases, tier, codec, orientation, audio-stream presence, documented shortened derivatives, and filename-level multi-recording cases.

The six low-volume Wave 1 records exercise short-duration, shortened, Pre-Standard, HEVC, landscape, and no-audio conditions before costly stress tests. Large and multi-recording cases remain in Wave 2 until Wave 1 establishes actual runtime and cost.

Wave 1 is published under artifacts/pilot-v1. It contains 6 silent proxies, 126 progress frames, 6 record manifests, summary.csv, and a run manifest. See PILOT_REPORT.md for the verified result and the failures that changed the pipeline.

Audio

source_has_audio records stream presence only. Proxies remove audio uniformly. This does not classify a source stream as music, speech, silence, or meaningful signal.

Work identity and completeness

record_id identifies a video object. work_id is reserved for a curator-verified physical drawing and remains null when that relationship has not been established. Rec01, shared dates, and similar filenames are not treated as proof of shared work identity or sequence.

Visible start state, visible end state, capture extent, and source-master status are separate fields. A completed-looking or signed endpoint never implies that the complete process was captured.

See DERIVATION_CONTRACT.md for the normative contract.

Reproduction

Generate the validation manifest from a pinned metadata snapshot:

python tools/select_validation_set.py \
  --standard-metadata metadata.csv \
  --prestandard-metadata Pre_Standard_Time_Lapses/metadata.csv \
  --source-revision 46e0be60f606635ee2b627be911bc98ab46565d3 \
  --output data/pipeline_validation_set.csv \
  --relationship-output data/work_relationship_review.csv

Process Wave 1 locally or in a Hugging Face Job:

python tools/generate_derivatives.py \
  --validation-repo maxwellinked/time-lapse-artifacts-derived \
  --validation-revision main \
  --pilot-wave 1 \
  --output-dir derived-output

The script records the complete FFmpeg build string. When a runtime lacks FFmpeg and FFprobe, its pinned PEP 723 dependency installs static binaries without elevated privileges.

Supplying --output-repo maxwellinked/time-lapse-artifacts-derived persists the results to the Hub. Each completed record is checkpointed before the next begins; run-level summary files are committed only after every selected record succeeds. --resume reuses locally completed record manifests after an interrupted run. Hub metadata requests and source downloads use four bounded attempts with exponential backoff; partial standard-HTTP downloads can continue on retry. Without --output-repo, no upload occurs.