How to save the audio from a video
- Drop an MP4, M4V, MOV or M4A into the box above.
- Read the Audio track in this file panel. It tells you the codec, the sample rate, the channel count and how many audio frames the track holds — before anything is done to it.
- Leave Copy without re-encoding selected unless you need uncompressed audio, then press Extract audio.
- Play it back on the page to check, then download.
Why copying beats converting
The audio inside a video is not raw sound. It is already a finished, compressed stream, almost always AAC, and the compression it went through was lossy: detail was discarded when the video was made and it is not coming back.
A converter takes that stream, decodes it back to samples, and compresses it again into MP3 or AAC. The second pass has no idea which detail the first pass already removed, so it removes more of what is left. You end up with a file that is smaller in quality than the audio the video was carrying, for no reason other than that the tool did not know how to simply copy it.
Copying skips both steps. The compressed frames are lifted out of the container exactly as they are, and the only thing added is the small header each frame needs so that a player can find it in a standalone file. That is why this tool prints the numbers after every run: how many bytes of audio came out, how many bytes of framing were added, and how many frames there were. Divide the second by the third and you get seven — seven bytes per frame, which is the entire cost of the operation.
| Route | What happens to the audio | Quality | Size |
|---|---|---|---|
| Copy (this tool's default) | Frames moved out of the container, headers added | Identical to the video's audio | Same as the audio inside the video |
| WAV | Decoded to raw samples, written uncompressed | No further loss | Roughly 10 MB per minute, stereo |
| MP3 conversion (what most tools do) | Decoded, then compressed again | A second round of loss | Similar to the original, sometimes larger |
Which one should you pick?
- Listening, archiving, sending to someone: copy. It is the same audio the video had, at the same size, and it takes a moment because nothing is decoded.
- Editing, transcribing, running through analysis software: WAV. Editors want uncompressed samples, and starting from WAV means any later conversion happens once, from lossless material.
- You were told to supply an MP3: take the WAV and convert that. Going MP4 to MP3 directly is two lossy passes; WAV to MP3 is one.
Why the file is .aac and not .mp3
Because that is honestly what came out. The audio in the video was AAC, so a copy of it is AAC, and calling it something else would mean converting it — the exact thing this tool exists to avoid. VLC, foobar2000, Winamp, most Android players, and every audio editor worth the name open a .aac file without comment.
A few consumer players are fussier about extensions than about contents, and would rather see .m4a or .mp3 even for audio they can decode perfectly well. If you are stuck with one of those, the WAV route sidesteps the problem entirely.
What cannot be copied
Containers outside the MP4 family — WebM, MKV — and codecs other than AAC, such as Opus or Vorbis, cannot be lifted out here. The tool does not pretend otherwise: it tells you what it found and why the copy route is unavailable, and offers WAV, which works because the browser can decode those formats even when this tool cannot repackage them.
Size, speed and limits
There is no upload and no cap. Copying is close to instant on any length of recording, because no audio is decoded at all. WAV takes longer and needs more memory, since the entire track has to be turned into raw samples before it can be written — and the result can be large enough to run into upload limits somewhere else, which is its own small nightmare.
If you wanted the pictures too
Video to frames exports the frames as PNG or JPG and shows you the frame count so you can see nothing was duplicated, and video to GIF makes a short animation from a stretch of the clip that can be fitted to a size limit.