New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Ffmpeg Encoder Check

by HKUDS in HKUDS/OpenSpace

Check FFmpeg encoder availability before video encoding to avoid library mismatches

MITAuto-check passedMedia & Creative

Install Ffmpeg Encoder Check

skills CLI
$ npx skills add HKUDS/OpenSpace --skill ffmpeg-encoder-check -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install HKUDS/OpenSpace ffmpeg-encoder-check --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/benchmarks/gdpval/skills/ffmpeg-encoder-check .claude/skills/ffmpeg-encoder-check && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
ffmpeg-encoder-check
GitHub stars
7.7k
Token cost
~894 tokens
SKILL.md length
294 words
Files
2
Skills in repo
199
Repo updated
First seen
Licence
MIT

At a glance

Check FFmpeg encoder availability before video encoding to avoid library mismatches

  • Works in 4 steps: Probe Available Encoders → Interpret Results → Choose Encoding Strategy → …
  • Tasks that involve Video production
  • SKILL.md covers Purpose, Instructions, Best Practices and Example Script Template, plus 1 more section
  • Calls ffmpeg

What it does

Ffmpeg Encoder Check is an agent skill from HKUDS/OpenSpace. Check FFmpeg encoder availability before video encoding to avoid library mismatches

Its SKILL.md is about 890 tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file.

It sits in Media & Creative, covering Video production. It works with FFmpeg. The repository describes itself as: "OpenSpace: The Skill Management Layer for AI Agents" -- https://open-space.cloud/. The licence is MIT.

When your agent uses it

  • Tasks that involve Video production

Example prompts

  • “/ffmpeg-encoder-check”

Workflow steps

4 steps, taken from the step headings in SKILL.md.

  1. Probe Available Encoders
  2. Interpret Results
  3. Choose Encoding Strategy
  4. Validate Before Batch Processing

What it can do on your machine

Read from SKILL.md and the folder at commit 3827781. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • ffmpeg

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Ffmpeg Encoder Check loads about 894 tokens when it runs. Until then it costs about 26 tokens; SKILL.md has 294 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~26
When it runs · the whole SKILL.md, loaded when a task matches
~894

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from HKUDS/OpenSpace at commit 3827781, republished under its MIT licence (© HKUDS). 294 words, ~894 tokens.

Download SKILL.mdSave it as .claude/skills/ffmpeg-encoder-check/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
ffmpeg-encoder-check
description
Check FFmpeg encoder availability before video encoding to avoid library mismatches

FFmpeg Encoder Availability Check

Purpose

Before writing video encoding scripts, always verify which H.264 encoders are available in your FFmpeg installation. This prevents failures from library version mismatches, particularly with libopenh264.

Instructions

Step 1: Probe Available Encoders

Run the following command to check available H.264 encoders:

bash
ffmpeg -encoders 2>/dev/null | grep h264

This shows which H.264 encoders are compiled into your FFmpeg build.

Step 2: Interpret Results

Common encoder options you may see:

EncoderDescriptionRecommendation
libx264Software H.264 encoderPreferred - widely compatible
libopenh264OpenH264 software encoderUse with caution - often has library version mismatches
h264_nvencNVIDIA hardware encoderGood if NVIDIA GPU available
h264_videotoolboxmacOS hardware encoderGood on macOS
h264_vaapiIntel VAAPI hardware encoderGood on Linux with Intel GPU
h264_qsvIntel QuickSync encoderGood on Windows/Linux with Intel GPU
Step 3: Choose Encoding Strategy

For same-resolution sources (no re-encoding needed):

bash
# Best option - pass-through without quality loss
ffmpeg -i input.mp4 -c:v copy -c:a copy output.mp4

If libx264 is available:

bash
# Reliable software encoding
ffmpeg -i input.mp4 -c:v libx264 -preset medium -crf 23 -c:a aac output.mp4

If only libopenh264 is available:

bash
# Use with caution - may have library issues
ffmpeg -i input.mp4 -c:v libopenh264 -c:a aac output.mp4
Step 4: Validate Before Batch Processing

Always test your encoding command on a small sample file before processing multiple videos or long footage.

Best Practices

  1. Default to -c:v copy when source and target resolutions match - no quality loss, fastest processing
  2. Prefer libx264 over libopenh264 for software encoding - more stable, better compatibility
  3. Check encoder availability at script startup, not during execution - fail fast with clear error
  4. Cache encoder check results if running multiple encoding operations in the same session
  5. Provide fallback options in automated scripts - try copy first, then libx264, then fail gracefully

Example Script Template

bash
#!/bin/bash

# Check available encoders at startup
ENCODERS=$(ffmpeg -encoders 2>/dev/null | grep h264)

if echo "$ENCODERS" | grep -q "libx264"; then
    VIDEO_CODEC="libx264"
    echo "Using libx264 encoder"
elif echo "$ENCODERS" | grep -q "libopenh264"; then
    VIDEO_CODEC="libopenh264"
    echo "Warning: Using libopenh264 (may have compatibility issues)"
else
    echo "Error: No H.264 encoder available"
    echo "Available encoders:"
    echo "$ENCODERS"
    exit 1
fi

# For same-resolution sources, prefer copy
if [ "$SOURCE_RESOLUTION" = "$TARGET_RESOLUTION" ]; then
    VIDEO_CODEC="copy"
    echo "Same resolution detected - using stream copy"
fi

# Encode
ffmpeg -i "$INPUT" -c:v "$VIDEO_CODEC" -c:a aac "$OUTPUT"

Common Errors to Avoid

  • Do not assume libx264 is available - FFmpeg builds vary by system
  • Do not use libopenh264 without checking - frequent library version mismatch errors
  • Do not re-encode unnecessarily - use -c:v copy when resolution matches
  • Do not skip the encoder check - always probe before writing encoding logic

© HKUDS, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file in benchmarks/gdpval/skills/ffmpeg-encoder-check of HKUDS/OpenSpace.

  • SKILL.md
  • .skill_id

Open the folder on GitHubat commit 3827781

Compare with similar skills

Ffmpeg Encoder Check next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Ffmpeg Encoder Check compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Ffmpeg Encoder Check this skillHKUDS/OpenSpace7.7k—~894Automated safety check: PassMIT
Video Understandcalesthio/OpenMontage65k—~841Automated safety check: PassAGPL-3.0
Video Shotseternityspring/reelbench-skills8682 repos~1.8kAutomated safety check: NotesApache-2.0
HyperFrames Video Entry Pointheygen-com/hyperframes59k3 repos~5.2kAutomated safety check: PassApache-2.0
Mobile Demo Film Editorsuperset-sh/superset15k—~1.8kAutomated safety check: PassCustom licence
Karaoke CaptionsAI-Builder-Club/skills1.3k1 repos~850Automated safety check: PassNone

Similar skills

  • Video Understand

    calesthio/OpenMontage

    Understand video content locally using ffmpeg frame extraction and Whisper transcription.

    65k GitHub stars~841 tokensUpdated 4 days ago
    Media & CreativeAuto-check passed

  • Video Shots

    eternityspring/reelbench-skills

    拉片：把一条成片拆成逐镜头的分析表——每个镜头的时长、景别、类别、运镜、画面. An agent skill from eternityspring/reelbench-skills.

    868 GitHub starsUsed in 2 repos~1.8k tokens
    Media & CreativeAuto-check: notes

  • HyperFrames Video Entry Point

    heygen-com/hyperframes

    Entry point for making, editing and rendering videos from HTML compositions with HyperFrames, routing each request to the right workflow.

    59k GitHub starsUsed in 3 repos~5.2k tokens
    Media & CreativeAuto-check passed

  • Mobile Demo Film Editor

    superset-sh/superset

    Edits real mobile screen recordings into a configurable demo video with phone framing, title cards, cutaways and an end card, using a bundled renderer.

    15k GitHub stars~1.8k tokensUpdated today
    Media & CreativeAuto-check passed

  • Karaoke Captions

    AI-Builder-Club/skills

    Generate TikTok/Shorts-style karaoke captions using MLX Whisper, ASS subtitles, and FFmpeg libass.

    1.3k GitHub starsUsed in 1 repo~850 tokens
    Media & CreativeAuto-check passed

  • Video Scrub

    eternityspring/reelbench-skills

    把一条视频重建成「只有画面和声音」的干净文件——源片的元数据一概不搬： GPS、设备型号、账号 ID、创建时间、章节、GoPro 的遥测轨，全部留在原地。

    868 GitHub starsUsed in 1 repo~1.3k tokens
    Media & CreativeAuto-check: notes

More from HKUDS/OpenSpace

All 199 skills in this repo

  • Audio Track Production Workflow

    HKUDS/OpenSpace

    Walks through producing a master audio track plus stems in Python, from checking a reference file and timing sections by BPM to effects, a zip archive and final verification.

    7.7k GitHub stars~2.9k tokensUpdated 1 mo ago
    Auto-check passed

  • Cascade Failure Recovery

    HKUDS/OpenSpace

    Handle cascading data retrieval tool failures by falling back to embedded knowledge generation

    7.7k GitHub stars~765 tokensUpdated 1 mo ago
    Auto-check passed

  • Sandbox Code Execution Fallback

    HKUDS/OpenSpace

    Gives an agent a workaround when its code-execution sandbox keeps failing: save the Python script to a file and run it through the shell instead.

    7.7k GitHub stars~588 tokensUpdated 1 mo ago
    Auto-check passed

  • Code Execution Fallback

    HKUDS/OpenSpace

    A recovery routine for agents whose sandboxed code runner keeps failing: save the Python script to disk, then run it through the shell and read the output.

    7.7k GitHub stars~652 tokensUpdated 1 mo ago
    Auto-check passed

  • Code Execution Fallback and Path Anchoring

    HKUDS/OpenSpace

    Fallback ladder for failed sandboxed code runs, plus the habit of fixing the working directory first so generated files land in the right place.

    7.7k GitHub stars~1.1k tokensUpdated 1 mo ago
    Auto-check passed

  • Code Execution Fallback E81068

    HKUDS/OpenSpace

    Fallback workflow for executing Python code when executecodesandbox fails repeatedly

    7.7k GitHub stars~1.1k tokensUpdated 1 mo ago
    Auto-check passed

Works with

Categories

Questions about Ffmpeg Encoder Check

What does Ffmpeg Encoder Check do?

Check FFmpeg encoder availability before video encoding to avoid library mismatches. Ffmpeg Encoder Check is an agent skill from HKUDS/OpenSpace.

When should I use Ffmpeg Encoder Check?

Ffmpeg Encoder Check fits situations like: tasks that involve Video production.

How do I install Ffmpeg Encoder Check in Claude Code?

Run `npx skills add HKUDS/OpenSpace --skill ffmpeg-encoder-check -a claude-code`. Or copy the skill folder (benchmarks/gdpval/skills/ffmpeg-encoder-check in HKUDS/OpenSpace) into .claude/skills/ffmpeg-encoder-check in your project. Claude Code loads it when a task matches its description.

How do I install Ffmpeg Encoder Check in Codex?

Run `npx skills add HKUDS/OpenSpace --skill ffmpeg-encoder-check -a codex`. Or copy the skill folder (benchmarks/gdpval/skills/ffmpeg-encoder-check in HKUDS/OpenSpace) into .agents/skills/ffmpeg-encoder-check in your project. Codex loads it when a task matches its description.

Can I use Ffmpeg Encoder Check in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add HKUDS/OpenSpace --skill ffmpeg-encoder-check -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/ffmpeg-encoder-check, .gemini/skills/ffmpeg-encoder-check, .github/skills/ffmpeg-encoder-check and .opencode/skills/ffmpeg-encoder-check in your project.

What does Ffmpeg Encoder Check need to run?

Going by SKILL.md and its folder, Ffmpeg Encoder Check needs the command-line tools its instructions call (ffmpeg).

Does Ffmpeg Encoder Check access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Ffmpeg Encoder Check safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Ffmpeg Encoder Check use?

Ffmpeg Encoder Check is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Ffmpeg Encoder Check use?

About 894 tokens (SKILL.md is roughly 3.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Ffmpeg Encoder Check?

Skills that share tags, products or a category with Ffmpeg Encoder Check: Video Understand (calesthio/OpenMontage, 65k stars), Video Shots (eternityspring/reelbench-skills, 868 stars), HyperFrames Video Entry Point (heygen-com/hyperframes, 59k stars) and Mobile Demo Film Editor (superset-sh/superset, 15k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Ffmpeg Encoder Check?

HKUDS (a GitHub organization) maintains it in HKUDS/OpenSpace, which has 7,749 GitHub stars. The repository holds 199 skills in this directory. The repository was last updated on August 12, 2026.

Source: HKUDS/OpenSpace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.