A tool for combining multiple MP4 videos into one video arranged as a grid, such as videos shown side by side or stacked.

Use it to compare recordings, create side-by-side videos, or combine videos into custom row-and-column layouts with optional labels.

It removes the need to place and align each video manually. It can keep the combined video running as long as the longest input and can handle large grids in streaming mode.

merge — Skill for Claude Code and Codex by phanghonghao

Install

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.

Any agent

npx skills add phanghonghao/THU-Awesome-Skills --skill merge

Clone the repo

git clone --depth 1 https://github.com/phanghonghao/THU-Awesome-Skills

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/phanghonghao/thu-awesome-skills/merge/github.svg)](https://agentmods.dev/skills/phanghonghao/thu-awesome-skills/merge)

Your own site

<a href="https://agentmods.dev/skills/phanghonghao/thu-awesome-skills/merge"><img src="https://agentmods.dev/badge/skills/phanghonghao/thu-awesome-skills/merge/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/phanghonghao/thu-awesome-skills/merge"><img src="https://agentmods.dev/badge/skills/phanghonghao/thu-awesome-skills/merge.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,322 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00074	$0.01322
Opus 5.5	$0.00030	$0.00529
Sonnet 5.5	$0.00015	$0.00264
Haiku 4.5	$0.00007	$0.00132

Measured 2mo ago against content hash 43089a007ac5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

merge 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 2mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (merge_videos.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/merge/SKILL.md · 124 lines

How it starts

The opening of the file, as written. The whole thing — 124 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Merge Videos

Merge multiple MP4 videos into a single grid-layout video with optional labels.

Permanent Script

The merge tool is the permanent CLI script next to this file:

<this skill directory>\merge_videos.py

After syncing to Claude with codex2claude, use the copied script in Claude's merge skill directory. Do not use hardcoded stale paths such as .claude-key3.

Do not generate temporary merge scripts. Always call this permanent script directly with python.

Templates

Template	Layout	Video Count	Description
`2x1`	2 rows, 1 col	2	Vertical stack of 2 videos
`3x1`	3 rows, 1 col	3	Vertical stack of 3 videos
`2x2`	2 rows, 2 cols	4	Square grid, TL TR BL BR
`3x2`	3 rows, 2 cols	6	Tall grid, 6 cells
`NxM`	N rows, M cols	N*M	Any arbitrary grid, auto-parsed

Auto-detect template when -t is omitted:

2 videos -> 2x1
3 videos -> 3x1
4 videos -> 2x2
6 videos -> 3x2

For any other count, pass -t, for example -t 8x4 for 32 videos.

Workflow

Find video paths from user arguments, globbing a directory when needed.
Determine the template from the user request or by auto-detect.
Auto-generate labels from filenames unless custom labels or --no-labels are requested.
Use --loop-to-longest when the user wants the longest video to define the full episode and shorter videos to replay.
Use --stream for large grids or long videos so encoded frames are written incrementally instead of held in memory.
Run the permanent script directly:

python "<this skill directory>\merge_videos.py" <video_paths> -t <template> --labels <labels...> -o <output>

Report output path, frame count, duration, resolution, and file size.

CLI Parameters

python merge_videos.py VIDEO [VIDEO ...] [-t TEMPLATE] [--labels LABEL [LABEL ...]]
                       [-o OUTPUT] [--gap N] [--fps N] [--font-size N] [--no-labels]
                       [--loop-to-longest] [--stream]
                       [--cell-width N] [--cell-height N]

Read the full file on GitHub · 124 lines

Files

What ships with it

1 file 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.

merge_videos.py 12 KB runs code

Changes

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.

2mo ago First seen · 124 lines · 74 tokens per session scan A 43089a007ac5

Subscribe to this mod's changes

merge is a skill published in the GitHub repository phanghonghao/THU-Awesome-Skills (8 stars, last pushed 3mo ago), licensed MIT. It adds 74 tokens to every session and 1,322 once invoked, about $0.0003 per session on Opus 5.5. 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.

Creative and media

merge next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
mergephanghonghao/THU-Awesome-Skills	Skill	8	3mo ago	MIT	A	74	Claude Code, Codex
imagegenopenai/codex	Skill	134k	today	Apache-2.0	A	113	Codex
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	yesterday	MIT	A	200	Claude Code, Codex
playwright-climicrosoft/playwright	Skill	100k	yesterday	Apache-2.0	A	19	Claude Code
browser-automationopenclaw/openclaw	Skill	394k	today	MIT	A	36	Claude Code
systematic-debuggingobra/superpowers	Skill	314k	4d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	today	MIT	A	95	Claude Code