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File ConvertersAn NCM file is a song downloaded from NetEase Cloud Music, and a KGM file is a song downloaded from Kugou Music. Both are encrypted containers: the original MP3 or FLAC audio is inside, but it is scrambled so that only the vendor’s own app can play it. VLC, Windows Media Player and phones show an error or silence. To use the music elsewhere, the file has to be decrypted and saved as a normal MP3 or FLAC.
What is an NCM file?
NetEase Cloud Music (网易云音乐) is one of the largest streaming services in China. When a subscriber downloads a track for offline listening, the app saves it with the .ncm extension instead of .mp3. The extension marks a DRM (digital rights management) container. It exists so that downloaded songs stay tied to an active NetEase account and cannot be copied to other players or shared.
| Property | NCM file | KGM file |
|---|---|---|
| Source app | NetEase Cloud Music | Kugou Music (酷狗音乐) |
| Extensions | .ncm | .kgm, .kgma (also .kgg in newer versions) |
| Inside | Encrypted MP3 or FLAC stream, metadata, cover art | Encrypted MP3 or FLAC stream |
| Plays in | NetEase Cloud Music app only, with a logged-in account | Kugou Music app only |
| Standard players | No | No |
Technically an NCM file starts with the magic string CTENFDAM, followed by an AES-128 encrypted key, a block of metadata (title, artist, album, original format and bitrate), the cover image, and the audio data scrambled with an RC4-style stream cipher. Nothing is re-encoded: once the stream is decrypted, you get the very same MP3 or FLAC file that NetEase served, at the original bitrate.
What is a KGM file?
Kugou Music uses the same idea with a different cipher. Downloads from the Kugou app carry the .kgm extension, or .kgma for tracks that were FLAC. Some newer client versions write .kgg files. Like NCM, a KGM file holds the untouched audio stream under an encryption layer, so the quality is whatever Kugou delivered, usually 128 or 320 kbps MP3 or lossless FLAC for VIP subscribers.
How do I open an NCM or KGM file?
Inside the vendor app it just plays. Log in to NetEase Cloud Music or Kugou Music with the account that downloaded the track, and the app decrypts it on the fly. Everything else fails: the file has no valid MP3 header, so players, phones, car stereos and editing software reject it. There is no codec to install; the only ways out are to stream the song again in the app or to convert the file.
How do I convert NCM or KGM to MP3?
Converting means decrypting the container and writing the audio back as a standard file. The NCM to MP3 online converter and the KGM to MP3 online converter do this in the browser: upload the file, download the MP3. Tracks that were FLAC inside come out at full quality. Open-source command-line unlockers exist as well and are the usual choice for large collections, but they need a terminal and, for the newest Kugou versions, a key extracted from the installed app.
After conversion, the songs behave like any other audio. To change bitrate, normalize volume or turn a folder of MP3 files into FLAC, WAV, AAC or OGG in one batch, use Total Audio Converter on Windows (30-day free trial, no card required).
Is converting NCM or KGM files legal?
The honest answer is: it depends on where you are and what you do with the result. The encryption is a DRM measure, and the terms of service of both NetEase and Kugou tell subscribers to play downloads only inside the app. Removing DRM for personal use of music you paid for is tolerated in some countries and prohibited in others. Redistributing the decrypted files is copyright infringement everywhere. Convert only tracks you have rights to, keep the copies for yourself, and check the law of your country before building a library this way.
Frequently asked questions
What is an NCM file?
An encrypted song downloaded from NetEase Cloud Music. It wraps an ordinary MP3 or FLAC stream, plus metadata and cover art, in a DRM container that only the NetEase app can play.
How do I convert NCM to MP3?
Upload the file to the NCM to MP3 online converter and download the result. The audio is decrypted, not re-encoded, so a 320 kbps download stays 320 kbps and a FLAC download stays lossless.
What is a KGM file?
The Kugou Music equivalent of NCM: an encrypted download that plays only in the Kugou app. The KGM to MP3 online converter unlocks it into a standard MP3.
Can I play NCM or KGM files in VLC?
No. VLC, foobar2000, Windows Media Player and phone players cannot decrypt the container and report an unsupported or corrupt file. Convert the file to MP3 first, then it plays anywhere.
Is it legal to convert NCM or KGM files?
It is a gray area. The files are DRM-protected and the apps’ terms of service restrict playback to the app. Personal use of music you paid for is treated differently from country to country; sharing decrypted files is illegal everywhere.
