Convert MKV to WAV
Extract uncompressed audio from an MKV as a WAV. Two things make this pair different from the other video-to-WAV conversions: MKV usually carries five or six channels of AC-3 or DTS rather than stereo, so the audio is mixed down on the way out, and MKV files are typically long, so the result can be very large indeed.
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Up to 50 MB. Deleted automatically after 30 minutes.
What it does
- The video stream is discarded, not re-encoded
- Multichannel audio mixed down to stereo
- Uncompressed 16-bit PCM output
- No watermark and no sign-up
How to use MKV to WAV
- 1
Trim first if the file is long
MKV holds films and episodes. Cut the section you need before uploading; the limit here is 50 MB and uncompressed audio is large.
- 2
Add the MKV
Drop the trimmed file in or choose it from your computer.
- 3
Convert and import
The video is dropped, the first audio track is decoded to 16-bit PCM and written as a WAV that any editor will read.
Two things that make this different
Extracting audio is a simple operation and MKV complicates it in two specific ways, both worth knowing before you start.
The first is channels. Matroska became the container of choice for high-quality video precisely because it carries whatever you put in it, and what people put in it is frequently AC-3 or DTS at five or six channels. WAV here is stereo, so those channels are folded together on the way out.
The second is length. MKV holds films, episodes and long recordings. Uncompressed audio costs about ten megabytes a minute, so an hour of it is six hundred megabytes, and the upload limit here is fifty. Trimming first is not optional for most MKV files.
How it works
The video stream is discarded — not decoded, simply not carried across — and the first audio track is decoded to 16-bit PCM samples written into a WAV. If that track has more than two channels it is mixed to stereo as part of the process.
No encoder runs on the output. WAV stores samples as they are, which is why every editor reads it and why the file is large.
What a downmix actually costs
Folding six channels into two is not a loss of fidelity so much as a loss of position. Every sound is still there; it is now sharing two channels with everything else.
For a film soundtrack the audible effect is that dialog sits less clearly in front of the music, because a center channel exists mainly to keep those apart. For music recorded in surround, instruments separated by position become separated only by level and frequency. For a talk recorded in stereo to begin with, nothing changes at all.
If placement matters to what you are doing, the MKV is the only copy that has it, and a desktop tool can extract the multichannel track without mixing anything.
Picking the right track
An MKV with several audio tracks gives you the first one here, which is usually but not always the one you want. MKVToolNix will list what is inside a file in a few seconds, and ffmpeg can pull out a specific track by index — and can do it without re-encoding, which is faster and lossless.
That is the better route for anything where the track choice matters.
Examples
Audio from a recorded talk for editing
Recording software often writes MKV, and an editor or transcription tool downstream wants uncompressed samples.
A surround soundtrack for analysis
Five or six channels are folded into two, which is what most analysis tools expect — and what they lose is placement rather than content.
Frequently asked questions
What happens to surround sound?
It is mixed to two channels. MKV is popular precisely because it carries multichannel AC-3 or DTS, and WAV here is stereo, so the extra channels are folded in. What you lose is placement rather than content — a sound deliberately positioned behind the listener arrives in the middle with everything else, and center-channel dialog sits alongside the music instead of in front of it.
Which track is taken if there are several?
The first one in the file. MKV commonly holds more than one — a second language, a commentary, a stereo mix alongside a surround one — and there is no way to choose here. If you need a particular track, a desktop tool such as ffmpeg or MKVToolNix will list them and let you pick, and can extract without re-encoding.
Why is the WAV so large?
Because uncompressed audio costs about ten megabytes a minute in stereo regardless of what it contains, and MKV files are usually long. An hour becomes roughly six hundred megabytes. Trimming to the section you actually need before uploading is the practical answer, and mono halves it again if your tool accepts mono.
Should I extract to WAV or MP3?
Whatever the destination requires. Editors, transcription engines and analysis tools frequently insist on uncompressed audio; anything you intend to listen to is better as an MP3, which is a tenth the size and sounds the same to a human. They are different jobs rather than better and worse options.