Media Converter は何をしますか？
Media Converter はブラウザ上でデータやファイルを変換するツールで、結果と制限を明確に示します。 検証済みの機能： WAV audio extraction, Capability-checked MP4 and WebM, Compatible-track remuxing, Resolution caps and hard cancellation.
When should you use this tool?
Use WAV extraction for an uncompressed audio copy, transcode when the target codec or dimensions must change, and remux to change compatible containers without re-encoding. A remux does not fix an unsupported playback codec and does not shrink video dimensions. Check the output in the application that will receive it.
使い方
- Choose a local media file, or load the two-second sample tone. Wait for the file and codec capability check.
- Select an enabled output operation and a video height cap for transcoding. Run Convert locally; Cancel terminates the Worker.
- Preview and download the result, then check it in your target player. Changing the file or settings clears the previous result.
実際の入出力例
Export a two-second local sample as WAV
入力
Sample tone: 2 seconds, 440 Hz, mono PCM, 48 kHz.
Operation: WAV audio extraction.出力
A downloadable WAV file with a 48 kHz, 16-bit mono PCM audio track, about 188 KiB.The sample is generated in this tab without a microphone. WAV uses built-in PCM processing. For compressed inputs, the original codec must also be decodable; video conversion depends on available encoders.
一般的なエラーと対処
| 症状 | 原因 | 対処 |
|---|---|---|
| MP4 or another operation is unavailable. | The file codec cannot be decoded or the requested encoder is unavailable. Container support alone does not guarantee encoding support. | Choose an enabled operation. Firefox may lack AAC encoding even when H.264 is available. WAV extraction or compatible remuxing may still work; the tool rejects accidental track loss. |
| The file is rejected or processing stops. | The media is encrypted, damaged, unsupported, or exceeds duration, dimension, frame, file, output or time budgets. | Use an unencrypted short mono/stereo file, shorten or resize it first, then recheck. No file is uploaded as a fallback. |
Supported behavior and limitations
このツール固有の制限： Inputs: local MP4/MOV/M4A, WebM/Matroska, WAV, MP3, Ogg, FLAC or AAC when their tracks are supported. Maximum 30 seconds; desktop 25 MiB, touch devices 10 MiB. Input video: 1920 × 1080 or rotated equivalent (touch 1280 × 720), 900 frames. Transcoded video: at most 1280 × 720, 30 fps (touch 854 × 480), never upscaled. Audio: 1–2 channels, 8–96 kHz; re-encoded audio is 48 kHz. Output budget is 25 MiB/10 MiB; inspection stops after 20 seconds and conversion after 90 seconds. Only primary video/audio tracks are used; subtitles and descriptive metadata are omitted. Remuxing preserves original codecs and dimensions; MP4 remuxing is limited to H.264/AAC. A browser preview may be unavailable even for a valid output. No MP3 encoder, HLS/URL import, DRM, 4K, arbitrary codec guarantee or server fallback. Physical-phone performance has not been validated; use small files on mobile.
標準と実装の参考資料
- Mediabunny official repository (opens in a new tab)Version 1.61.4, MPL-2.0; the complete corresponding source archive and license are linked in the workspace. No optional codec plugins are included.
- Mediabunny formats and codec support (opens in a new tab)Separates container compatibility from native WebCodecs encoding/decoding. The tool checks the actual tracks and requested configuration.
Media Converter — FAQ
Is my input uploaded?
No. Processing happens in a browser Worker. Engine files load from this website; tool input, output, and filenames are not sent to a processing API.
Do I need an account or API key?
No account, API key, or backend processing service is needed.
How do I save a result?
Review the result, then use the Copy or Download control available for that output. Modifying input clears stale results.
What are the limits?
Inputs: local MP4/MOV/M4A, WebM/Matroska, WAV, MP3, Ogg, FLAC or AAC when their tracks are supported. Maximum 30 seconds; desktop 25 MiB, touch devices 10 MiB. Input video: 1920 × 1080 or rotated equivalent (touch 1280 × 720), 900 frames. Transcoded video: at most 1280 × 720, 30 fps (touch 854 × 480), never upscaled. Audio: 1–2 channels, 8–96 kHz; re-encoded audio is 48 kHz. Output budget is 25 MiB/10 MiB; inspection stops after 20 seconds and conversion after 90 seconds. Only primary video/audio tracks are used; subtitles and descriptive metadata are omitted. Remuxing preserves original codecs and dimensions; MP4 remuxing is limited to H.264/AAC. A browser preview may be unavailable even for a valid output. No MP3 encoder, HLS/URL import, DRM, 4K, arbitrary codec guarantee or server fallback. Physical-phone performance has not been validated; use small files on mobile.
更新内容
実質的な更新： Media Converter: Added local processing, explicit size limits, cancellation, worked examples, error explanations, and downloadable results.