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 jakenuts/agent-skills --skill ffmpeg-toolkitgit clone --depth 1 https://github.com/jakenuts/agent-skillsWrote 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/jakenuts/agent-skills/ffmpeg-toolkit)<a href="https://agentmods.dev/skills/jakenuts/agent-skills/ffmpeg-toolkit"><img src="https://agentmods.dev/badge/skills/jakenuts/agent-skills/ffmpeg-toolkit.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 | $0.00060 | $0.02991 |
| Opus 5 | $0.00030 | $0.01496 |
| Sonnet 5 | $0.00012 | $0.00598 |
| Haiku 4.5 | $0.00006 | $0.00299 |
Grade A, and why
ffmpeg-toolkit 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 8d 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.
How it starts
The opening of the file, as written. The whole thing — 271 lines — stays where its author put it; the contents beside it link to each section on GitHub.
FFmpeg Toolkit
Transcode
# Convert to MP4 (H.264 + AAC)
ffmpeg -i input.mov -c:v libx264 -preset medium -crf 23 \
-c:a aac -b:a 128k output.mp4
# Convert to WebM (VP9 + Opus)
ffmpeg -i input.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 \
-c:a libopus -b:a 128k output.webm
Resize
# Specific dimensions
ffmpeg -i input.mp4 -vf "scale=1920:1080" output.mp4
# Aspect-ratio preserve with padding (letterbox/pillarbox)
ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2" output.mp4
# Crop to fill (no black bars)
ffmpeg -i input.mp4 -vf "scale=1920:1080:force_original_aspect_ratio=increase,crop=1920:1080" output.mp4
# Scale to width, auto height
ffmpeg -i input.mp4 -vf "scale=1280:-2" output.mp4
# Scale to percentage (50%)
ffmpeg -i input.mp4 -vf "scale=iw/2:ih/2" output.mp4
Trim and Cut
# Cut from timestamp + duration (re-encode recommended for accuracy)
ffmpeg -i input.mp4 -ss 00:00:30 -t 00:00:15 -c:v libx264 -c:a aac output.mp4
# Cut from start to end timestamp
ffmpeg -i input.mp4 -ss 00:00:30 -to 00:00:45 -c:v libx264 -c:a aac output.mp4
# Stream copy (faster, but may lose frames at non-keyframe cut points)
ffmpeg -i input.mp4 -ss 00:00:30 -t 00:00:15 -c copy output.mp4
# Fast seek for large files (put -ss before -i)
ffmpeg -ss 00:10:00 -i large_video.mp4 -t 00:05:00 -c copy clip.mp4
Note: Re-encoding is recommended for trimming. Stream copy (-c copy) can silently drop video if the seek point doesn't align with a keyframe.
Speed Adjustment
# 2x speed (video and audio)
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" \
-map "[v]" -map "[a]" output.mp4
# 0.5x speed (slow motion)
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]atempo=0.5[a]" \
-map "[v]" -map "[a]" output.mp4
# Video only (no audio)
ffmpeg -i input.mp4 -filter:v "setpts=0.5*PTS" -an output.mp4
# Extreme slow motion (0.25x) - chain atempo filters (each limited to 0.5-2.0)
ffmpeg -i input.mp4 -filter_complex "[0:v]setpts=4.0*PTS[v];[0:a]atempo=0.5,atempo=0.5[a]" \
-map "[v]" -map "[a]" output.mp4
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 8d ago First seen · 271 lines · 60 tokens per session scan A f385febeb1a5
ffmpeg-toolkit is a skill published in the GitHub repository jakenuts/agent-skills (2 stars, last pushed 1mo ago), licensed MIT. It adds 60 tokens to every session and 2,991 once invoked, about $0.0003 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 2026-08-31.
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