video-merger

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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.

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Source SKILL.md: https://github.com/opensquilla/opensquilla/blob/HEAD/src/opensquilla/skills/bundled/video-merger/SKILL.md

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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).