Refine README academic wording

README.md

@@ -10,7 +10,7 @@ license: other
 
 # Video-Progress Benchmark Release
 
-Video-Progress Benchmark is a benchmark for long-horizon robot manipulation progress prediction. This release provides benchmark JSON files, the minimal raw-video subset required by the released protocol, and a lightweight frame-extraction workflow for reproducible evaluation.
+Video-Progress Benchmark is a benchmark for evaluating progress prediction in long-horizon robot manipulation. This release provides the benchmark split files, the minimal subset of raw videos required by the benchmark protocol, and a frame-extraction workflow for reproducible evaluation.
 
 ## Contents
 
@@ -39,7 +39,7 @@ data/
 bash scripts/extract_vlac2_release_raw_archives.sh
 ```
 
-This extracts `data/train_videos.tar` and `data/test_videos.tar` into `data/`.
+This command extracts `data/train_videos.tar` and `data/test_videos.tar` into `data/`, while preserving the relative directory structure expected by the benchmark release.
 
 To extract the raw videos elsewhere, pass a target directory:
 
@@ -53,7 +53,7 @@ bash scripts/extract_vlac2_release_raw_archives.sh /path/to/data
 python scripts/extract_vlac2_release_frames.py --data-root data
 ```
 
-By default, extracted frames are written to `_extracted_frames/` under the release directory. Only the benchmark main view is extracted.
+By default, extracted frames are written to `_extracted_frames/` under the release directory. The extractor materializes only the benchmark-designated main camera stream.
 
 If the raw videos were extracted elsewhere:
 
@@ -63,7 +63,7 @@ python scripts/extract_vlac2_release_frames.py --data-root /path/to/data
 
 ### 3. Use the benchmark splits
 
-The benchmark JSON files are ready to use. No benchmark reconstruction is required.
+The benchmark JSON files are pre-generated and can be used directly. No benchmark reconstruction is required.
 
 Frame paths in the JSON files use the prefix:
 
@@ -71,7 +71,7 @@ Frame paths in the JSON files use the prefix:
 __VLAC2_FRAMES_ROOT__/
 ```
 
-Replace `__VLAC2_FRAMES_ROOT__` with the absolute path to the extracted-frame directory.
+Replace `__VLAC2_FRAMES_ROOT__` with the absolute path to the extracted-frame directory produced by the frame-extraction step.
 
 For example, if frames are extracted to:
 
@@ -101,11 +101,11 @@ The release contains one training split and four evaluation splits:
 * `test_nonexpert_seen`
 * `test_nonexpert_unseen`
 
-The test splits are intended for evaluation only.
+The four test splits are intended for evaluation only.
 
 ## Dependencies
 
-A video decoder backend is required for frame extraction. Install one of:
+A video decoder backend is required for frame extraction. Install one of the following:
 
 ```bash
 pip install opencv-python
@@ -121,7 +121,7 @@ pip install imageio imageio-ffmpeg
 
 ## Notes
 
-* This repository only contains the raw videos required by the released benchmark splits.
+* This repository contains only the raw videos required by the released benchmark splits.
 * The full raw-data release is distributed separately.
-* The benchmark JSON files are pre-generated and ready to use.
-* The raw-video archives and extracted-frame cache are separated so that users can regenerate frames under their own storage layout.
+* The benchmark JSON files are canonical release artifacts and do not need to be rebuilt.
+* The raw-video archives and the extracted-frame cache are intentionally separated so that users can regenerate frames under their own storage layout.