HyperFrames Animation
heygen-com/hyperframes
Collects motion rules, scene blueprints, transitions and runtime adapters for HyperFrames video compositions, with GSAP as the default animation runtime.
Two-pass video concatenation workflow that avoids encoder compatibility issues by separating concat and audio mixing
Install Safe Video Concat Workflow
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflow --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .claude/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.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/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .claude/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflowType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflow --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .agents/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .agents/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .agents/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflow --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .cursor/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .cursor/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/HKUDS/OpenSpace.git --path benchmarks/gdpval/skills/safe-video-concat-workflow--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflow --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .gemini/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .gemini/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflowInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .github/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .github/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .github/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install HKUDS/OpenSpace safe-video-concat-workflow --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/HKUDS/OpenSpace.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/benchmarks/gdpval/skills/safe-video-concat-workflow .opencode/skills/safe-video-concat-workflow && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "safe-video-concat-workflow" agent skill from https://github.com/HKUDS/OpenSpace/tree/main/benchmarks/gdpval/skills/safe-video-concat-workflow into .opencode/skills/safe-video-concat-workflow/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "safe-video-concat-workflow", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
safe-video-concat-workflow- GitHub stars
- 7.8k
- Token cost
- ~777 tokens
- SKILL.md length
- 235 words
- Files
- 2
- Skills in repo
- 199
- Repo updated
- First seen
- Licence
- MIT
At a glance
Two-pass video concatenation workflow that avoids encoder compatibility issues by separating concat and audio mixing
- Works in 4 steps: Probe Source Videos → Use Stream Copy When Resolution Matches → Build Concat List with Bare Filenames → …
- Tasks that involve Video production
- SKILL.md covers When to Use, Step 1: Probe Source Videos, Step 2: Use Stream Copy When… and Step 3: Build Concat List with…, plus 3 more sections
- Calls ffmpeg and ffprobe
What it does
Safe Video Concat Workflow is an agent skill from HKUDS/OpenSpace. Two-pass video concatenation workflow that avoids encoder compatibility issues by separating concat and audio mixing
Its SKILL.md is about 780 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. 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
- “/safe-video-concat-workflow”
Workflow steps
4 steps, taken from the step headings in SKILL.md.
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:
ffmpegffprobe
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
Safe Video Concat Workflow loads about 777 tokens when it runs. Until then it costs about 36 tokens; SKILL.md has 235 words of instructions outside code blocks.
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). 235 words, ~777 tokens.
Download SKILL.mdSave it as
.claude/skills/safe-video-concat-workflow/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- safe-video-concat-workflow
- description
- Two-pass video concatenation workflow that avoids encoder compatibility issues by separating concat and audio mixing
Safe Video Concatenation Workflow
This workflow prevents encoder compatibility failures when creating video showreels or compilations by using a two-pass approach: concatenate video clips first, then add music/SFX in a separate pass.
When to Use
- Creating video showreels from multiple source clips
- Adding background music or sound effects to concatenated videos
- Avoiding encoder errors when combining clips with audio mixing
Step 1: Probe Source Videos
Before processing, verify resolution and duration of all source clips using ffprobe:
# Get video resolution
ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=p=0 clip.mp4
# Get video duration
ffprobe -v error -show_entries format=duration -of csv=p=0 clip.mp4Record the resolution (e.g., 1920x1080) to determine if stream copy is safe.
Step 2: Use Stream Copy When Resolution Matches
If source clips already match your target resolution, use -c:v copy to avoid re-encoding:
# Good: avoids encoder issues when resolution matches
-c:v copy
# Only re-encode if resolution conversion is needed
-c:v libx264 -s 1920x1080This prevents encoder compatibility failures that can occur with complex filter chains.
Step 3: Build Concat List with Bare Filenames
Create the concat list file with bare filenames only (no directory prefixes):
file 'clip1.mp4'
file 'clip2.mp4'
file 'clip3.mp4'Important: Run ffmpeg from the same directory as the video clips, or the concat demuxer may fail to find files.
cd /path/to/clips
ffmpeg -f concat -safe 0 -i file_list.txt ...Step 4: Two-Pass Processing
Pass 1: Concatenate Video Clips
Concatenate all clips first into an intermediate file:
ffmpeg -f concat -safe 0 -i file_list.txt -c:v copy -c:a aac -y interim.mp4Pass 2: Add Music/SFX with Complex Filter
Apply audio mixing or other complex filters in a separate pass:
ffmpeg -i interim.mp4 -i background_music.mp3 \
-filter_complex "[0:a][1:a]amix=inputs=2:duration=first:dropout_transition=3" \
-c:v copy -c:a aac -y final_output.mp4Why Two Passes?
Combining concatenation and audio mixing in a single command can cause:
- Encoder compatibility failures
- Resource exhaustion
- Complex filter chain errors
The two-pass approach isolates concerns and ensures each operation completes successfully.
Quick Reference Commands
# Probe resolution
ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=p=0 VIDEO.mp4
# Create concat list (bare filenames, run from clip directory)
echo "file 'clip1.mp4'" > concat_list.txt
echo "file 'clip2.mp4'" >> concat_list.txt
# Pass 1: Concatenate
ffmpeg -f concat -safe 0 -i concat_list.txt -c:v copy -c:a aac -y interim.mp4
# Pass 2: Add audio
ffmpeg -i interim.mp4 -i music.mp3 -filter_complex "[0:a][1:a]amix=inputs=2" -c:v copy -y output.mp4© 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/safe-video-concat-workflow of HKUDS/OpenSpace.
- SKILL.md
- .skill_id
Open the folder on GitHubat commit 3827781
Compare with similar skills
Safe Video Concat Workflow 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.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Safe Video Concat Workflow this skillHKUDS/OpenSpace | 7.8k | — | ~777 | Automated safety check: Pass | MIT | |
| HyperFrames Animationheygen-com/hyperframes | 60k | 3 repos | ~2.1k | Automated safety check: Pass | Apache-2.0 | |
| Stitch to Remotion Walkthrough Videosgoogle-labs-code/stitch-skills | 8.5k | 6 repos | ~3.2k | Automated safety check: Notes | Apache-2.0 | |
| Faceless Explainer Videoheygen-com/hyperframes | 60k | 3 repos | ~7.7k | Automated safety check: Notes | Apache-2.0 | |
| Video Understandcalesthio/OpenMontage | 66k | — | ~841 | Automated safety check: Pass | AGPL-3.0 | |
| Video ShotcraftVincentwei1021/video-shotcraft | 11k | — | ~2.6k | Automated safety check: Pass | Apache-2.0 |
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Related
Categories
Questions about Safe Video Concat Workflow
What does Safe Video Concat Workflow do?
Two-pass video concatenation workflow that avoids encoder compatibility issues by separating concat and audio mixing. Safe Video Concat Workflow is an agent skill from HKUDS/OpenSpace.
When should I use Safe Video Concat Workflow?
Safe Video Concat Workflow fits situations like: tasks that involve Video production.
How do I install Safe Video Concat Workflow in Claude Code?
Run `npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a claude-code`. Or copy the skill folder (benchmarks/gdpval/skills/safe-video-concat-workflow in HKUDS/OpenSpace) into .claude/skills/safe-video-concat-workflow in your project. Claude Code loads it when a task matches its description.
How do I install Safe Video Concat Workflow in Codex?
Run `npx skills add HKUDS/OpenSpace --skill safe-video-concat-workflow -a codex`. Or copy the skill folder (benchmarks/gdpval/skills/safe-video-concat-workflow in HKUDS/OpenSpace) into .agents/skills/safe-video-concat-workflow in your project. Codex loads it when a task matches its description.
Can I use Safe Video Concat Workflow 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 safe-video-concat-workflow -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/safe-video-concat-workflow, .gemini/skills/safe-video-concat-workflow, .github/skills/safe-video-concat-workflow and .opencode/skills/safe-video-concat-workflow in your project.
What does Safe Video Concat Workflow need to run?
Going by SKILL.md and its folder, Safe Video Concat Workflow needs the command-line tools its instructions call (ffmpeg and ffprobe).
Does Safe Video Concat Workflow 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 Safe Video Concat Workflow 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 Safe Video Concat Workflow use?
Safe Video Concat Workflow 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 Safe Video Concat Workflow use?
About 777 tokens (SKILL.md is roughly 3.1k 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 Safe Video Concat Workflow?
Skills that share tags, products or a category with Safe Video Concat Workflow: HyperFrames Animation (heygen-com/hyperframes, 60k stars), Stitch to Remotion Walkthrough Videos (google-labs-code/stitch-skills, 8.5k stars), Faceless Explainer Video (heygen-com/hyperframes, 60k stars) and Video Understand (calesthio/OpenMontage, 66k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Safe Video Concat Workflow?
HKUDS (a GitHub organization) maintains it in HKUDS/OpenSpace, which has 7,754 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.