Video conversion
Convert MKV to AAC
Updated Jul 2026
Converting MKV to AAC means pulling the audio track out of the video and saving it as a standalone AAC file, since AAC can't hold video at all. To do it, open the MKV in a converter, choose AAC as the output, and convert. Doing this on your own computer means the video file never has to be uploaded anywhere.
- Extension
- .mkv
- Type
- Video
- Typically
- High-quality video containers
- Extension
- .aac
- Type
- Audio
- Typically
- Apple / streaming audio
- Compression
- Lossy
Convert MKV to AAC on your own computer. Nothing uploads.
How to convert MKV to AAC
- Open Morphjet and drag in the MKV file or folder of files you want the audio from.
- Choose AAC as the output format. Morphjet pulls the audio track and re-encodes it.
- Convert. The AAC file is written next to your original, and the video never leaves your machine.
MKV vs AAC: what actually changes
| MKV | AAC | |
|---|---|---|
| Holds video | Yes | No, audio only |
| File size | Large, often gigabytes | Much smaller, tens of megabytes |
| Quality | Lossless or near-lossless audio and video | Lossy, compressed audio |
| Opens everywhere | No, needs a capable media player | Yes, plays on nearly any device or app |
| Subtitles and multiple tracks | Can hold several audio tracks and subtitles | No, single audio track only |
| Keeps chapter and tags metadata | Yes | Partial, basic tags only |
When to convert, and when not to
Convert MKV to AAC when you only want the sound from a video, like a lecture, podcast recording, concert, or commentary track, and you want it as a small file you can play on a phone or in a music app.
Keep the MKV if you still want to watch the video, because converting to AAC throws away the picture, subtitles, and any extra audio tracks for good.
Why not just use an online converter?
MKV files are often large recordings, lectures, or personal videos that people don't want sitting on someone else's server just to pull out the audio. An online converter has to receive the whole video file before it can hand back an AAC. Converting on your own computer means the video, and whatever it shows, never gets uploaded at all.
Questions
Does converting MKV to AAC lose quality?
The audio does lose a little quality, since AAC is a compressed format and the original audio in an MKV is often lossless or near-lossless. For speech, podcasts, and most casual listening the difference isn't noticeable.
What happens to the video when I convert MKV to AAC?
It's discarded. AAC is an audio-only format, so the conversion keeps the sound and drops the picture, subtitles, and any other tracks in the MKV.
Can I choose which audio track to convert if the MKV has more than one?
Yes, if the MKV contains multiple audio tracks, such as different languages or a commentary track, you pick which one becomes the AAC file.
Will the AAC file keep any of the MKV's metadata?
Basic tags can carry over, but chapter markers, subtitles, and anything tied to the video itself don't, since AAC has no place to store them.
Can I convert MKV to AAC without uploading the video file?
Yes. A desktop app like Morphjet reads the MKV and writes the AAC on your own computer, so the video never has to travel over the internet.
Morphjet converts MKV, AAC, and 1,800+ other formats, all on your machine. Launching this July.