Convert MP4 to Opus
Free online converter for MP4 files. Low-latency codec with excellent quality at low bitrates. Nothing to install, no watermark, and every file is deleted automatically.
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Upload a MP4 file to convert it to Opus. Up to 3 files at once, 100 MB each.
Free · up to 3 files · 100 MB each · files deleted automatically after 1 hour.
About MP4 and OPUS
MP4 .mp4
The universal video container, normally holding H.264 video and AAC audio. If a device plays video at all, it plays MP4.
Good for
- Plays on effectively every device, browser and editor
- Excellent compression at high quality
- Streams well, and seeks quickly
Trade-offs
- H.264 carries patent licensing obligations
- Lossy — quality drops each time it is re-encoded
- Less flexible than MKV for subtitles and multiple tracks
video/mp4
Opus .opus
The current state of the art in lossy audio, standardised by the IETF. It outperforms MP3 and AAC across the range and is dramatically better at low bitrates.
Good for
- Best quality per byte of any format here
- Excellent for speech as well as music
- Open, royalty-free, and low latency
Trade-offs
- Lossy
- Older devices and some players will not open it
- Less familiar, so people distrust the file extension
audio/opus
MP4 and OPUS side by side
| MP4 | OPUS | |
|---|---|---|
| Compression | Lossy (usually H.264) | Lossy |
| Transparency | No | n/a |
| Typically used for | Everything — the safe default for video | Voice, streaming, bandwidth-limited audio |
What changes when you convert MP4 to OPUS
Only the sound is kept
This takes the audio track out of the MP4 and writes it as OPUS. The picture is discarded entirely, and no conversion back will return it — keep the MP4 if you still need the video.
This is a re-encode, not a repackage
Some tools can move a stream into a different container untouched when the codecs happen to line up. We do not — every job here is decoded and encoded again, so the conversion takes time in proportion to the length of the file and costs a small amount of quality even where a repackage would have been possible. In exchange the output is predictable: it plays everywhere, rather than inheriting whatever the source happened to contain.
What your OPUS will contain
The output is Opus — encoded with Vorbis at 192 kbps by default. Vorbis is royalty-free and holds up slightly better than MP3 at the same bitrate, though Opus has largely superseded it for new work.
Other MP4 conversions
Other ways to get Opus
Worth reading next
MP4, MOV and MKV are not really video formats
The extension on a video file tells you far less about it than most people assume. Understanding the difference between a container and a codec explains almost every confusing thing about video conversion.
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What 192 kbps actually means, and when you need more
Bitrate is the single dial that decides how big an audio file is and how good it sounds. Here is what the numbers mean, why they are not comparable between codecs, and where the real thresholds sit.
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