Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add cxcscmu/SkillLearnBench --skill ffmpeg-keyframesgit clone --depth 1 https://github.com/cxcscmu/SkillLearnBenchWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/cxcscmu/skilllearnbench/ffmpeg-keyframes)<a href="https://agentmods.dev/skills/cxcscmu/skilllearnbench/ffmpeg-keyframes"><img src="https://agentmods.dev/badge/skills/cxcscmu/skilllearnbench/ffmpeg-keyframes.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00024 | $0.00225 |
| Opus 5 | $0.00012 | $0.00112 |
| Sonnet 5 | $0.00005 | $0.00045 |
| Haiku 4.5 | $0.00002 | $0.00022 |
Grade A, and why
ffmpeg-keyframes scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
FFmpeg Key Frame Extraction
Overview
Extract I-frames (keyframes) from video files. Keyframes are complete frames that don't depend on other frames for decoding.
Command
ffmpeg -i input.mp4 -vf "select=eq(pict_type\,I)" -vsync vfr output_%03d.png
Flags
-vf "select=eq(pict_type\,I)": Select only I-frames (key frames)-vsync vfr: Variable frame rate to avoid duplicate frames%03d: Zero-padded 3-digit numbering
Output
Produces files like output_001.png, output_002.png, etc. in timeline order.
Verify
ffprobe -i input.mp4 -select_streams v -show_frames -show_entries frame=pict_type | grep -c "pict_type=I"
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago First seen · 29 lines · 24 tokens per session scan A 60763976798f
ffmpeg-keyframes is a skill published in the GitHub repository cxcscmu/SkillLearnBench (83 stars, last pushed 1mo ago), licensed MIT. It adds 24 tokens to every session and 225 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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Transcribe audio segments to text using Whisper models. Use larger models (small, base, medium, large-v3) for better accuracy, or faster-whisper for optimized performance. Always align transcription timestamps with diarization segments for accurate speaker-labeled subtitles.