Convert MP4 to MKV: Free Online Converter
Convert MPEG-4 Part 14 to Matroska Video online for free. Fast, secure video conversion with no watermarks or registration.
MP4に対応
アップロードすることで、これらのファイルの権利を有していること、および利用規約に同意することを確認したものとみなされます。
変換設定: ファイルを追加すると調整できます
安全な転送
HTTPS暗号化アップロード
プライバシー優先
ゲストのファイルは約2時間で自動削除
登録不要
すぐに変換を開始
どこでも動作
あらゆるブラウザ、あらゆるデバイス
MP4 から MKV への設定
- エンジン
- メディア
- 設定
- 調整できる設定: 31
- Trim Start
- Trim End
- Volume
- Audio Fade In
- Audio Fade Out
- Video Codec
- Quality (CRF)
- Encoding Speed
- Profile
- Level
- Tune
- Resolution
変換方法
アップロードエリアにドラッグするか、クリックして選択し、.mp4ファイルをアップロードしてください。
必要に応じて出力設定を調整してください。デフォルト設定ではオリジナルの品質を維持します。
「変換」をクリックし、準備ができたら.mkvファイルをダウンロードしてください。
MP4からMKVへの変換について
MP4 to MKV conversion repackages your MPEG-4 video into the Matroska container format. MKV is an open-standard container that can hold virtually unlimited numbers of video, audio, and subtitle tracks in a single file. Unlike MP4, which has restrictions on supported codecs, MKV accepts everything from H.264 and H.265 to VP9, AV1, FLAC, DTS, and bitmap subtitles.
Our converter performs a stream copy by default: remuxing the existing video and audio streams from the MP4 into an MKV container without re-encoding. This is essentially instant and produces zero quality loss. The MKV container adds support for features like ordered chapters, soft subtitles in ASS/SSA format, and multiple audio tracks.
MP4をMKVに変換する理由
MKV is the format of choice for media archivists and home theater enthusiasts. It supports features that MP4 cannot: multiple subtitle tracks in various formats (SRT, ASS, VobSub), lossless audio codecs (FLAC, DTS-HD MA, TrueHD), chapter navigation with ordered chapters, and tagging systems for detailed metadata. If you are building a media library managed by Plex, Jellyfin, or Kodi, MKV is the preferred container because it holds all tracks in one file without compromise.
主な活用例
- Repackage MP4 files for Plex, Jellyfin, or Kodi media libraries
- Add multiple subtitle tracks (SRT, ASS) to a video in a single file
- Combine video with multiple audio tracks (commentary, different languages)
- Archive video with lossless FLAC audio instead of lossy AAC
- Add chapter markers for navigation in long videos like lectures or films
- Preserve all streams when MP4 codec restrictions prevent certain combinations
仕組み
FFmpeg uses -c copy to remux MP4 streams into the MKV container without transcoding. The Matroska container uses EBML (Extensible Binary Meta Language) for its structure, which is more flexible than MP4's atom-based layout. MKV supports an unlimited number of tracks, ordered chapters via XML chapter files, segment linking for split-file playback, and rich tagging with the Matroska tag specification. CRC-32 checksums can be embedded per cluster for data integrity verification.
品質とパフォーマンス
When remuxing (stream copy), quality is identical to the source MP4 — no re-encoding occurs. The video and audio bitstreams are transferred verbatim into the new container. File size may differ by a few kilobytes due to the different container overhead, but the media data is unchanged.
デバイス互換性
| Device | MP4 | MKV |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Native | Partial |
| Linux | Partial | Partial |
| Web Browser | Native | No |
プラットフォーム別の推奨設定
YouTube
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
TikTok
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Twitter/X
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Discord
Resolution: 1280x720
Bitrate: 4 Mbps
8MB free, 50MB Nitro
最良の結果を得るためのヒント
- 1Use remux mode (stream copy) unless you need to change the codec — it is instant and lossless
- 2Add chapter markers for long videos to enable navigation in media players
- 3Embed subtitle files as tracks rather than separate files for single-file convenience
- 4MKV is ideal for Plex/Jellyfin — organize with correct naming for automatic metadata matching
- 5Use MKVToolNix after conversion to add or edit tracks, chapters, and metadata
関連する変換
MP4 to MKV is a quick remux that unlocks Matroska's rich feature set — multiple tracks, flexible subtitle support, chapters, and universal codec compatibility — without touching your actual video or audio quality.
MP4とMKVの比較
| 特徴 | MP4 | MKV |
|---|---|---|
| 正式名称 | MPEG-4 Part 14 | Matroska Video |
| 拡張子 | .mp4 | .mkv |