Skip to main content
Convert999
フォーマットすべての変換ツール比較活用事例ToolsBlog
変換ツール
Convert999

400以上の形式をサポートする無料オンラインファイル変換ツール。

製品

  • すべての変換ツール
  • フォーマット
  • 比較
  • 活用事例
  • Tools

リソース

  • 概要
  • Blog
  • Security
  • Glossary
  • Statistics
  • Changelog
  • Contact

法的情報

  • プライバシーポリシー
  • 利用規約

© 2026 Convert999. All rights reserved.

Made with for the web

HomeFormatsMP4
.mp4

MP4 Converter

Convert MPEG-4 Video files online for free — no upload, no registration, 100% private

動画 format
ファイルを選択

またはファイルをここにドラッグ＆ドロップ

最大ファイルサイズ：2GB

ファイルはブラウザ内でローカルに処理されます。サーバーにアップロードされません。

What is a MP4 file?

MPEG-4 Video (.mp4)

MP4 (MPEG-4 Part 14) is the world's most widely used video container format, standardized as ISO/IEC 14496-14. MP4 can contain video (H.264, H.265/HEVC, AV1), audio (AAC, MP3, AC-3), subtitles (SRT, ASS), and metadata in a single file. H.264/AVC is the most common video codec in MP4 files, providing excellent quality at reasonable file sizes. MP4 supports 4K, 8K, HDR (HDR10, Dolby Vision), 360° video, and multiple audio tracks. It's the default video format for smartphones, digital cameras, streaming services (YouTube, Netflix), social media platforms, and web browsers. MP4 files are natively playable on virtually every device and operating system without additional software. The format supports fast seeking, progressive download, and adaptive streaming (DASH). For web video, MP4 with H.264 video and AAC audio provides the widest compatibility.

Extension: .mp4Category: 動画

Convert from MP4

Convert your MPEG-4 Video files to other formats

MP4AVIMP4MKVMP4MOVMP4WMVMP4FLVMP4WEBMMP4M4VMP4MPGMP4MPEGMP43GPMP43G2MP4VOBMP4OGVMP4TSMP4M2TSMP4MTSMP4SWFMP4ASFMP4DVMP4F4VMP4DIVXMP4XVIDMP4RMMP4RMVB

Convert to MP4

Convert other files to MPEG-4 Video format

AVIMP4MKVMP4MOVMP4WMVMP4FLVMP4WEBMMP4M4VMP4MPGMP4MPEGMP43GPMP43G2MP4VOBMP4OGVMP4TSMP4M2TSMP4MTSMP4SWFMP4ASFMP4DVMP4F4VMP4DIVXMP4XVIDMP4RMMP4RMVBMP4

Frequently Asked Questions about MP4

What is a MP4 file?
A MP4 file is a video format with the extension .mp4. MPEG-4 Video files are widely used in digital workflows for creating, sharing, and storing video content.
How do I convert MP4 files for free?
Use Convert999 to convert MP4 files for free directly in your browser. Simply upload your file, select the target format, and click convert. No installation or signup required.
Is it safe to convert MP4 files online?
Yes! Convert999 processes all files 100% locally in your browser. Your MP4 files are never uploaded to any server, ensuring complete privacy and security.
What formats can I convert MP4 to?
Convert999 supports converting MP4 to 24+ formats including AVI, MKV, MOV, WMV, FLV and more. Browse the full list above.

Explore MP4

MP4 Converter

MP4 → all formats

Convert to MP4

All sources → MP4

動画

All video formats

File Tools

Compress, resize, merge

Other 動画 Converters

.aviAudio Video Interleave.mkvMatroska Video.movApple QuickTime Movie.wmvWindows Media Video.flvFlash Video.webmWebM Video.m4vMPEG-4 Video.mpgMPEG Video.mpegMPEG Video.3gp3GPP Video.3g23GPP2 Video.vobDVD Video Object.ogvOgg Video.tsMPEG Transport Stream.m2tsBlu-ray BDAV.mtsAVCHD Video.swfShockwave Flash.asfAdvanced Systems Format