MP4 Converter Free & Private
The universal video container for every device. Convert MPEG-4 Video files entirely in your browser — no upload, no account.
About MPEG-4 Video
MP4 (MPEG-4 Part 14) is the world's most widely adopted video container format, standardised by ISO in 2003. It wraps H.264, H.265, or VP9 video alongside AAC or MP3 audio into a single file that plays natively on virtually every device — from smartphones and smart TVs to web browsers and game consoles. Its combination of efficient compression and universal playback makes it the default choice for video sharing, streaming, and archival.
Technical details
| Container | MPEG-4 Part 14 (.mp4, .m4v, .m4a) |
| Video codecs | H.264/AVC, H.265/HEVC, MPEG-4 Part 2, VP9, AV1 |
| Audio codecs | AAC, MP3, AC-3, Opus, FLAC, ALAC |
| Max resolution | 8K (7680×4320) |
| Streaming | Progressive download, DASH, HLS (fMP4) |
| Metadata | Full (title, artist, chapters, cover art, GPS) |
Best for
General-purpose video sharing, social media, web streaming, and cross-device playback
Advantages
- Plays on every major platform without conversion
- Excellent compression-to-quality ratio with H.264/H.265
- Supports multiple audio tracks, subtitles, and chapters
- Ideal for both streaming and local playback
Limitations
- Editing requires re-encoding unless using lossless codecs
- Patent-encumbered H.264/H.265 codecs (though widely licensed)
- Large files at high quality and resolution
Convert other formats to MP4
MP4 compatibility
All web browsers, iOS, Android, Windows, macOS, Linux, smart TVs, Chromecast, Roku, gaming consoles
Why privacy matters for file conversion
Most online converters upload your files to remote servers where they may be scanned, stored, or shared. This tool is different — the conversion runs in your browser via WebAssembly or the WebCodecs API. Your files stay on your device. Always.
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Frequently asked questions
MP4 is a container, not a codec. It can hold H.264, H.265, VP9, or AV1 video alongside AAC, MP3, Opus, or FLAC audio. The codec determines quality and compression.
It depends on the codec inside. Most MP4 files use lossy codecs like H.264 + AAC for smaller files, but MP4 can also hold lossless codecs like FLAC or Apple Lossless (ALAC).
M4V is Apple's variant of MP4, sometimes with FairPlay DRM. An unprotected .m4v file is identical to .mp4 — just rename the extension.
Yes, completely free with no file limits. The conversion engine runs directly in your browser — we have zero server costs for processing, so we can offer it at no charge.
Your file never leaves your device. The conversion engine runs 100% in your browser using WebAssembly or the WebCodecs API. We have no access to your files — no uploads, no logs, no data collection whatsoever.
On desktop browsers (Chrome, Firefox, Edge) files up to 500 MB convert reliably. On Safari (macOS) the practical limit is around 200 MB. On iPhone and iPad, keep files under 50 MB — iOS enforces tight memory limits for browser-based processing.
On your first visit, the browser downloads the conversion engine (24–50 MB depending on which backend is used). This is cached locally, so subsequent conversions load much faster.
Chrome, Edge, and Brave use hardware-accelerated WebCodecs when the format is supported — this is 5–10× faster than software encoding. For unsupported formats the tool falls back to ffmpeg.wasm, where Firefox typically performs best.
Utterly is a privacy-first transcription app for Apple devices. It uses on-device AI to transcribe and translate audio — no cloud, no subscription required to start. This free converter is brought to you by the Utterly team.