Convert MPEG-4 Audio (.m4a) to Matroska Video (.mkv) online for free. Fast, secure audio conversion with no watermarks or registration.
Upload your .m4a file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .mkv file when it's ready.
MKV (Matroska Video) is a versatile open container that supports virtually every audio and video codec. Converting M4A to MKV packages the audio inside a Matroska container, which is useful for combining audio with video tracks, adding subtitle streams, or preparing audio for media server libraries (Plex, Jellyfin, Kodi) that organize content in MKV format. The AAC audio from M4A can be stream-copied directly into MKV without re-encoding.
MKV supports multiple audio tracks, chapter markers, attachments, and metadata in ways that M4A does not. If you need to combine M4A audio with a video track, subtitles, or additional audio tracks (commentary, different languages), MKV is the standard container. Media server software like Plex indexes MKV files with their full track metadata, making MKV the preferred format for organized media libraries.
FFmpeg performs a stream copy of the AAC audio from the M4A container into an MKV container. The AAC bitstream is transferred bit-for-bit with no re-encoding. MKV (Matroska) uses EBML encoding and supports AAC natively with codec ID A_AAC. ALAC from M4A can also be muxed into MKV (codec ID A_ALAC). The operation is nearly instant since no transcoding occurs.
Stream copy mode preserves the exact audio quality from the M4A source. No re-encoding means zero quality change. The MKV container is a transparent wrapper.
| Device | M4A | MKV |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Resolution: N/A
Bitrate: 256 kbps
AAC format required
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
M4A to MKV is a fast, lossless container swap useful for media library organization, multi-track packaging, and compatibility with Matroska-based workflows.
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| No |
| Egenskap | M4A | MKV |
|---|---|---|
| Fullt navn | MPEG-4 Audio | Matroska Video |
| Filendelse | .m4a | .mkv |
| Best egnet for | Better than MP3 | Multiple audio tracks |