Convert MKV to M4A — Free Online Converter

M4A is an MPEG-4 audio container that typically holds AAC or ALAC audio streams, widely supported across Apple, Android, and Windows devices. Extracting audio from MKV to M4A produces a feature-rich audio file that supports metadata, chapters, album art, and gapless playback — advantages that raw AAC or MP3 files lack.

M4A is the preferred audio format for iTunes, Apple Music, and Apple Podcasts because it supports the full range of metadata Apple's ecosystem expects: artwork, lyrics, chapter markers, and podcast episode information. If you are extracting audio from MKV recordings for distribution through Apple's platforms, M4A is the correct output format.

Compared to MP3, M4A with AAC encoding delivers noticeably better audio quality at the same bitrate, especially at lower bitrates below 128 kbps. The M4A container also supports gapless playback, which is critical for live albums, classical music, and DJ mixes where silence between tracks ruins the listening experience.

FFmpeg extracts the audio from the MKV container and either stream-copies existing AAC audio directly into the M4A container (if the MKV already has AAC) or transcodes from the source codec to AAC using libfdk_aac or the native encoder. The M4A container is technically an MP4 file with only audio streams, identified by the .m4a extension. Metadata tags are mapped from the MKV using FFmpeg's metadata handling, including title, artist, album, track number, and embedded cover art.