Update root README for N-back transfer bundle

README.md

@@ -1,36 +1,102 @@
 # N-back_1
 
-This dataset package is prepared for building multi-video N-back video-memory sequences.
+This repository is a private transfer bundle for building multi-video N-back sequences.
 
-## What Is Included
+It contains:
+
+- raw source videos
+- pair manifests
+- pre-cut segment packages
+
+## Main Idea
+
+Each pair contains two highly similar videos from the same dataset.
+
+The intended similarity structure is:
+
+- within the same pair: highly similar
+- across different pairs from the same dataset: generally similar
+- across different datasets: relatively dissimilar
+
+This makes the package suitable for constructing both:
+
+- more similar source pools
+- less similar source pools
+
+In practice, a simple workflow is:
+
+1. Choose one pair as the anchor pair.
+2. If you want another similar source pair, choose a different pair from the same dataset.
+3. If you want a less similar source pair, choose a pair from a different dataset.
+4. Use either the raw videos or the pre-cut segment packages below.
+
+## Repository Layout
+
+### Raw Pair Package
 
 - `pairs/nback_1_pairs_20_per_dataset.json`
-  A combined manifest with 20 selected pairs from each dataset.
+  Combined manifest with 20 selected pairs from each dataset.
 - `pairs/<dataset>_pairs.json`
   Per-dataset manifests for easier browsing.
 - `pairs/manifest_summary.json`
-  A small summary file with counts.
+  Summary counts.
 - `videos/<dataset>/<pair_id>/video_1.mp4`
 - `videos/<dataset>/<pair_id>/video_2.mp4`
 
-Each pair contains two highly similar videos.
+The raw package is the right choice if you want to cut or sample the videos yourself.
 
-## Similarity Structure
+### Pre-cut Packages
 
-- Within the same pair: the two videos are highly similar.
-- Across different pairs from the same dataset: the videos are generally similar, but less tightly matched than within a pair.
-- Across different datasets: the videos are intended to be dissimilar.
+Pre-cut segment bundles are stored under folders such as:
 
-## Suggested Usage For N-back Construction
+- `precut_subsets/...`
+- `precut_full_20pairs_per_dataset_seg10/...`
 
-One simple way to build a video sequence is:
+Each pre-cut package has its own README and manifest.
+These are the right choice if you want to start directly from equal-count video segments.
 
-1. Pick one pair as the anchor pair.
-2. Pick another pair from the same dataset if you want a more similar source pool.
-3. Pick another pair from a different dataset if you want a less similar source pool.
-4. Use the videos from those pairs as candidate source videos for your N-back sequence.
+## Recommended Usage
 
-## Manifest Fields
+### If You Want Raw Videos
+
+1. Open `pairs/nback_1_pairs_20_per_dataset.json`.
+2. Choose one pair as the anchor pair.
+3. Choose another pair from the same dataset if you want a more similar source pool.
+4. Choose another pair from a different dataset if you want a less similar source pool.
+5. Read the corresponding raw files from:
+   `videos/<dataset>/<pair_id>/video_1.mp4`
+   and
+   `videos/<dataset>/<pair_id>/video_2.mp4`
+
+This is the recommended path if you want full control over:
+
+- how many clips to cut from each video
+- clip duration
+- ordering strategy
+- prompt construction
+
+### If You Want Pre-cut 10-Way Segments
+
+1. Open the README inside the corresponding pre-cut folder.
+2. Use the package manifest there to locate segment files.
+3. Each source video is split into:
+   `seg00` to `seg09`
+4. Use the manifest time fields as the planned time windows for downstream construction.
+
+This is the recommended path if you want to move quickly and do not want to cut videos on your own server.
+
+## Example Sequence Construction
+
+Suppose you want to build one source pool for a multi-video N-back sequence.
+
+1. Pick one anchor pair from `pairs/nback_1_pairs_20_per_dataset.json`.
+2. Use the two videos in that pair as a highly similar base.
+3. Add another pair from the same dataset if you want more semantically related videos.
+4. Or add a pair from a different dataset if you want a less similar source pool.
+5. If you use a pre-cut package, read the corresponding `seg00` to `seg09` files directly.
+6. If you use raw videos, cut them with your own strategy.
+
+## Pair Manifest Fields
 
 The pair JSON files include:
 
@@ -44,8 +110,9 @@ The pair JSON files include:
 - `repo_video_1_path`
 - `repo_video_2_path`
 
-`original_video_*_path` records the original local benchmark path used by the packer.
-`repo_video_*_path` records the path of the corresponding file inside this dataset package.
+`repo_video_*_path` is the path inside this Hugging Face repository.
+
+The per-pair JSON also keeps the selection metadata used during pair construction, which can help if you want to reuse the same sampling logic.
 
 ## Datasets Covered
 
@@ -58,5 +125,8 @@ The pair JSON files include:
 
 ## Notes
 
-- The videos are taken from the original local benchmark datasets used in VideoMemoryEval.
-- This package is intended as a transfer bundle for N-back construction work.
+- The videos come from the original benchmark datasets used in VideoMemoryEval.
+- Some pre-cut packages are produced with fast ffmpeg stream-copy segmentation.
+- In those packages, downstream users should rely on the manifest time windows rather than assuming frame-perfect physical cut points.
+- If you only need one urgent subset, check the `precut_subsets/` folder first.
+- If you want the complete 20-pairs-per-dataset transfer bundle with 10-way cuts, use `precut_full_20pairs_per_dataset_seg10/`.