ffmpeg-nl2cmd-clean: audited and split NL -> ffmpeg commands

A cleaned, audited and split version of burak29/Natural_Language_to_Ffmpeg_Commands (MIT license, by burak29) for training small models that translate a plain-English description into one executable ffmpeg command.

What was done

1. Audit (see scripts/audit.py): every command was executed against tiny synthetic media (lavfi testsrc/sine/color, 12s 640x480 video with audio and subtitle streams; image sequences; glob dirs). Commands needing hardware (nvenc/qsv), network (rtsp/srt/udp/rtp) or uncreatable inputs (.vob, .h264, .ac3, ...) were static-validated instead (filter/encoder/muxer existence).
2. Dedup: 6 exact + 6 near-duplicate pairs removed (1,030 -> 1,024 rows).
3. Labels: runs (804, exit 0), static-only (80, passed static validation), fails (140, genuine failures - e.g. unescaped commas in filter args, unquoted parentheses, removed options like -map_channel, wrong filter usage like avectorscope as a transform filter).
4. Fixes (logged in edits): 2 rows with a second -af overriding the first were merged into one filter chain.
5. Splits: 80/10/10 train/val/test grouped by main filter or codec family (151 families). A deliberate subset of rare families (<=2 rows) is assigned to test so the test set contains filter families absent from train (unseen_families_in_test). fails rows keep split="" and are excluded from training and evaluation.
6. Robustness slice (201 rows, split="test-robust"): test prompts rewritten with different filenames (applied consistently to prompt AND command) and rule-based rephrasing. Never applied to train/val.

Columns

• natural_language, ffmpeg_command: original pair (command possibly fixed, see edits)
• label: runs | static-only | fails | dup
• split: train | val | test | test-robust | empty for fails/dups
• category: video filter / audio filter / conversion / trim / concat / streaming
• filter_family: main filter or codec of the command
• reason: audit failure reason (fails rows)
• robustness_notes, source_id: provenance of robustness variants

License and attribution

Source dataset: burak29/Natural_Language_to_Ffmpeg_Commands, MIT license. The source is synthetically generated and its author warns it contains inaccuracies; the audit labels here quantify - but do not fully resolve - that. Some reference commands that execute are still semantically wrong, and static-only commands were never executed. Review before use.