Home / shiguredo / mp4-rs · GitHub

shiguredo-mp4 SKILL.md skillA

shiguredo-mp4 from shiguredo/mp4-rs is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned
mdr add shiguredo/mp4-rs/shiguredo-mp4@git:20260925.37d8584

Pins git:20260925.37d8584 in mdr.lock. Pin the fingerprint instead.

Audit grade
A, 17 of 17 checks passed
Kind
SKILL.md skill
Repository
shiguredo/mp4-rs
Path
skills/shiguredo-mp4/SKILL.md
Versions recorded
7
Latest version
git:20260925.37d8584, committed Sep 25, 2026
First version recorded
Aug 3, 2026
Size
24,274 bytes
Repository stars
159
License
Apache-2.0

時雨堂の Sans I/O MP4 ライブラリ shiguredo_mp4 の機能・API リファレンス。MP4 / fMP4 ファイルの mux/demux、ボックス群のエンコード・デコード、コーデック別サンプルエントリー、ISO/IEC 14496 系規格準拠に関する質問時に使用。.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# shiguredo_mp4

Sans I/O 設計に基づく MP4 (ISO Base Media File Format) の mux/demux ライブラリ。

## 特徴

- **依存なし**: 外部依存ゼロ (`core` / `alloc` のみ)
- **`no_std` 対応**: `std` 非依存 (`alloc` クレートは必要)
- **Sans I/O**: I/O を完全に分離した設計。ファイル読み書きは利用側の責務
- **高レベル API**: `Mp4FileMuxer` / `Mp4FileDemuxer` / `Fmp4SegmentMuxer` / `Fmp4SegmentDemuxer` による mux/demux
- **ボックス単位の API**: 全ボックスが `Encode` / `Decode` を実装し、直接エンコード/デコード可能
- **C API / WebAssembly API**: `crates/c-api` / `crates/wasm` で提供

## バージョン情報

- crate 名: `shiguredo_mp4`
- バージョン: 2026.5.0
- Rust Edition: 2024
- 最小 Rust バージョン: 1.93
- ライセンス: Apache-2.0

## 基本概念

MP4 ファイルは `ftyp` + 各種ボックス（`moov` / `mdat` / `moof` 等）で構成される。
すべてのボックスは `BaseBox` トレイトを実装し、`Encode` / `Decode` トレイトでバイト列と相互変換できる。

| 型 | 説明 |
|----|------|
| `BaseBox` | 全ボックスの共通トレイト (`box_type()` / `children()`) |
| `BoxHeader` | ボックスヘッダー (`box_type` + `box_size`)。`decode_header_and_payload()` でヘッダーとペイロードに分解 |
| `BoxSize` | ボックスのサイズ表現。`U32(u32)` / `U64(u64)`。`VARIABLE_SIZE` (`U32(0)`) は「ファイル末尾まで」を意味する |
| `BoxType` | ボックス種別。`Normal([u8; 4])` / `Uuid([u8; 16])` |
| `FullBox` / `FullBoxHeader` | version + flags を持つボックス用トレイト/ヘッダー |
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint
mdr add shiguredo/mp4-rs/shiguredo-mp4@sha256:1c1b0994f1b00971

The line at the top of this page pins the label git:20260925.37d8584, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_hjgscu26iyc4lnr7.svg)](https://markdownregistry.com/a/art_hjgscu26iyc4lnr7)

2 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 7 versions of this file, between Aug 3, 2026 and Sep 25, 2026, about one every 9 days.

versioncommittedcommitsizeaudit
git:20260925.37d8584 latest2026-09-25 37d8584 24,274 BA view · diff
git:20260925.d4e38882026-09-25 d4e3888 23,825 BA view · diff
git:20260925.49de9342026-09-25 49de934 23,728 BA view · diff
git:20260925.a82209c2026-09-25 a82209c 23,629 BA view · diff
git:20260924.ee0c84c2026-09-24 ee0c84c 23,485 BA view · diff
git:20260821.1e1f7a12026-08-21 1e1f7a1 23,485 BA view · diff
git:20260803.0bee1692026-08-03 0bee169 23,338 BA view

Audit of the latest version

A  17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (24274 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

shiguredo/mp4-rs · 159 stars · license Apache-2.0 · pushed 2026-10-07 · branch develop

API

GET https://markdownregistry.com/api/v1/artifacts/art_hjgscu26iyc4lnr7
GET https://markdownregistry.com/api/v1/resolve?ref=shiguredo/mp4-rs/shiguredo-mp4
GET https://markdownregistry.com/api/v1/blob/1c1b0994f1b00971dfb7a6e799ca80a686ef29d9f575c4d60b1c7b33007e0f01

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

More from shiguredo/mp4-rs

AGENTS.md AGENTS.md file
shiguredo/mp4-rs · AGENTS.md
git:20260924.324f57c · audit A · 159 stars

Every file in shiguredo/mp4-rs

Browse by kind, by grade A, or by owner.