How do I install the Video Merger skill?

Run npx skillmds@latest add gabrielmoreira/video-merger in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Video Merger safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: docs only. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Video Merger?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Video Merger free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Video Merger?

gabrielmoreira (@gabrielmoreira) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Video Merger by gabrielmoreira — Agent Skill

Name: Video Merger
Rating: 4.2 (5 reviews)
Author: gabrielmoreira

Video Merger

Concatenate a directory of numbered MP4 segments (1_*.mp4, 2_*.mp4, ...) into one MP4 with optional fade transitions, unified resolution/fps/codec. Pure ffmpeg wrapper, no LLM. Trigger when a workflow has produced several short clips that need stitching into a final reel.

gabrielmoreira Updated Sep 9, 2026 17 repo stars

File contents

video-merger — numbered-segment MP4 concatenator

Combines 1_*.mp4, 2_*.mp4, ... in numeric order into one MP4 (or multiple ~60s chunks), with optional fade transitions, codec/resolution/ fps normalisation.

Inputs (`with:`)

key	required	default	notes
`input_dir`	yes	—	Directory containing `\d+_*.mp4` segments.
`output_path`	yes	—	`.mp4` path (full mode) or directory (chunk mode).
`mode`	no	`full`	`full` or `chunk`.
`transition`	no	`0.5`	Fade duration in seconds. `0` disables.
`fps`	no	`24`	Target frame rate.
`crf`	no	`22`	x264 CRF (0-51, lower = better).
`preset`	no	`medium`	x264 preset.

For chunk mode, pass chunk_duration directly to the script — the meta engine entrypoint above does not template it; use a direct shell call when chunking is needed.

Dependencies

ffmpeg ≥ 5.0
ffprobe
Python 3.8+
No Python packages required beyond stdlib.

Install hints (or just run the bundled installer):

OS	One-liner installer	Manual
Windows (PowerShell)	`pwsh -ExecutionPolicy Bypass -File install.ps1`	`winget install Gyan.FFmpeg` / `choco install ffmpeg` / `scoop install ffmpeg`
macOS	`bash install.sh`	`brew install ffmpeg`
Debian/Ubuntu	`bash install.sh`	`sudo apt install ffmpeg`

The Windows installer (install.ps1) defaults to winget but accepts $env:OPENSQUILLA_FFMPEG_INSTALLER="choco"|"scoop"|"skip" to switch backends. It prints the absolute ffmpeg/ffprobe paths after install so you can pass them to merge.py via --ffmpeg-path / --ffprobe-path when subprocess PATH inheritance is unreliable.

Filename ordering contract

The script picks files matching ^\d+_.*\.mp4$ and sorts by the leading integer. Producers must save segments as 1_shot.mp4, 2_shot.mp4, 3_shot.mp4, etc. The meta-short-drama workflow already follows this.

Output

Stdout: progress lines and the final output path. Non-zero exit on ffmpeg failure.

Failure modes

未找到ffmpeg → install ffmpeg, ensure ffmpeg on PATH or pass --ffmpeg-path directly.
未找到符合命名规则...的MP4文件 → ensure segments are \d+_*.mp4.
Mixed resolutions / fps: handled automatically when --resolution is set; otherwise ffmpeg preserves originals (no normalisation).

---name: video-mergerdescription: Concatenate a directory of numbered MP4 segments (1_*.mp4, 2_*.mp4, ...) into one MP4 with optional fade transitions, unified resolution/fps/codec. Pure ffmpeg wrapper, no LLM. Trigger when a workflow has produced several short clips that need stitching into a final reel.--- # video-merger — numbered-segment MP4 concatenator Combines `1_*.mp4`, `2_*.mp4`, ... in numeric order into one MP4 (or multiple ~60s chunks), with optional fade transitions, codec/resolution/ fps normalisation. ## Inputs (`with:`) | key | required | default | notes | |---|---|---|---| | `input_dir` | yes | — | Directory containing `\d+_*.mp4` segments. | | `output_path` | yes | — | `.mp4` path (full mode) or directory (chunk mode). | | `mode` | no | `full` | `full` or `chunk`. | | `transition` | no | `0.5` | Fade duration in seconds. `0` disables. | | `fps` | no | `24` | Target frame rate. | | `crf` | no | `22` | x264 CRF (0-51, lower = better). | | `preset` | no | `medium` | x264 preset. | For chunk mode, pass `chunk_duration` directly to the script — the meta engine entrypoint above does not template it; use a direct shell call when chunking is needed. ## Dependencies - `ffmpeg` ≥ 5.0 - `ffprobe` - Python 3.8+ - No Python packages required beyond stdlib. Install hints (or just run the bundled installer): | OS | One-liner installer | Manual | |---|---|---| | Windows (PowerShell) | `pwsh -ExecutionPolicy Bypass -File install.ps1` | `winget install Gyan.FFmpeg` / `choco install ffmpeg` / `scoop install ffmpeg` | | macOS | `bash install.sh` | `brew install ffmpeg` | | Debian/Ubuntu | `bash install.sh` | `sudo apt install ffmpeg` | The Windows installer (`install.ps1`) defaults to winget but accepts `$env:OPENSQUILLA_FFMPEG_INSTALLER="choco"|"scoop"|"skip"` to switch backends. It prints the absolute `ffmpeg`/`ffprobe` paths after install so you can pass them to `merge.py` via `--ffmpeg-path` / `--ffprobe-path` when subprocess PATH inheritance is unreliable. ## Filename ordering contract The script picks files matching `^\d+_.*\.mp4$` and sorts by the leading integer. Producers must save segments as `1_shot.mp4`, `2_shot.mp4`, `3_shot.mp4`, etc. The `meta-short-drama` workflow already follows this. ## Output Stdout: progress lines and the final output path. Non-zero exit on ffmpeg failure. ## Failure modes - `未找到ffmpeg` → install ffmpeg, ensure `ffmpeg` on PATH or pass `--ffmpeg-path` directly. - `未找到符合命名规则...的MP4文件` → ensure segments are `\d+_*.mp4`. - Mixed resolutions / fps: handled automatically when `--resolution` is set; otherwise ffmpeg preserves originals (no normalisation).

Frequently asked questions