How to use
- lecture.mp42 audio tracks
Add a video or audio file
- lecture (audio)1:23–5:00
Pick the track and time range
- lecture.m4ano video kept
Save in the format you choose
Drop a video or an audio file, or click “Choose file”. If there are several audio tracks, choose the one to use.
Choose an output format (MP3, M4A, WAV, Opus or FLAC; only the ones this browser can write are listed). For MP3, M4A and Opus you can also choose a bitrate.
Optionally enter a start and an end time to take out only that part. Empty boxes mean the start and the end.
Click “Convert”, play the result to check it, then save. Several files can be saved together as a ZIP.
What it does
Audio from video
Takes the sound out of MP4, MOV, WebM or MKV video and drops the picture. When there are several audio tracks, you choose which one to keep.
No re-encoding for AAC
When the source audio is AAC, M4A is written by copying it, so the quality is unchanged and it is quick.
Cut by start and end time
Write times like 83.5, 1:23 or 1:02:03 and only that range is converted.
Check before you save
Shows the length, format, bitrate and size of the result, and lets you play it in the browser first.
Read in pieces
The file is read a little at a time rather than loaded whole into memory, and you can stop a conversion part way.
Use cases
- Take the audio out of a recorded meeting or interview for transcription
- Save only the music or narration from a phone video as WAV
- Change an M4A to Opus (OGG) to make the file smaller
- Cut out part of a lecture video and save it as an audio file
Supported formats
Input
Output
Capability matrix
| Feature | Support | Notes |
|---|---|---|
| Taking the audio out of video (picture dropped) | Supported | — |
| Choosing an audio track when there are several | Supported | — |
| Copying AAC to M4A without re-encoding | Supported | When the source is already AAC, the chosen bitrate has no effect and the audio is copied as it is |
| Cutting by start and end time | Supported | — |
| Writing WAV (16-bit) | Supported | — |
| Writing M4A and Opus | Partial | Only in browsers with WebCodecs encoders (checked in Chrome; Safari and Firefox support is limited) |
| Writing FLAC | Partial | Listed only when this browser can write FLAC |
| Writing MP3 | Supported | LAME (an open-source MP3 encoder) runs in your browser. About 0.3 MB is loaded the first time you choose MP3 |
| Loudness normalisation and noise removal | Not supported | — |
| DRM-protected (encrypted) video or audio | Not supported | Cannot be read |
| Keeping tags (title, artist and so on) | Not supported | The output has no tags |
| Writing video | Not supported | The picture is not kept; this tool is for audio |
Limits & notes
- Up to 2 GB and 4 hours per file on a PC. Phones: 300 MB and 1 hour.
- Up to 10 files at a time.
- WAV grows with the length (1 hour of 48 kHz stereo is about 690 MB). A WAV that would exceed the limit is refused before conversion starts.
- Files that are damaged, or use an unsupported format or DRM, cannot be read.
Privacy & safety
Reading, converting and saving all happen in your browser. The file is never sent to a server.
FAQ
How do I get only the audio from a video?
Can I convert MP4 to MP3?
Does the quality go down?
Is my video uploaded?
What if conversion fails?
Related tools
Music Tag Studio
Edit and save the tags of MP3 and FLAC files in one table. Title, artist, album, track number, year, genre, lyrics and album art are supported, and garbled Shift_JIS tags common in old Japanese MP3s can be re-read and saved as UTF-8 / UTF-16. Audio data is not changed by a single byte, and everything stays on your device.
Microphone Test
Start the mic to see input level (dBFS), waveform and spectrum. Clipping, noise and mute are detected automatically, and a guided speak test rates whether your mic is good enough for meetings. Nothing is uploaded.
Subtitle Studio
Open a subtitle file (SRT, WebVTT, ASS/SSA, SBV, TTML or LRC), edit it in a list and convert it to another format. Shifting, two-point stretching, frame-rate fixes and checks for overlaps and reading speed all run in your browser.
Audio Editor
To cut unwanted parts of audio, drag on the waveform to select a range and press “Remove selected ranges”. To join clips, use “Join and edit” to set the order and any silence between them. You can save as WAV or MP3, or as M4A or Opus where your browser can write them. Your file is never uploaded.
Audio Noise Removal
To reduce background noise in a recording or meeting, choose the audio or video, set the strength and click “Remove noise”. Compare the result with the original, then save it as 16-bit WAV. Your file is never uploaded.
Volume Normalization and LUFS
When sound is quiet, or the volume differs from file to file, set it to a target in LUFS. -14 suits YouTube and Spotify, -16 Apple Podcasts, and -23 broadcast. The tool measures first, then changes only the gain, and keeps the true peak under -1 dBTP. Your file is never uploaded.
Last updated: