MPEG-4 Part 14

Writable

audio

digital multimedia format most commonly used to store video and audio

Identify it

Extensions.mp4.m4a.m4p.m4b.m4r.m4v
MIME typesaudio/mp4video/mp4
Signatures
00000020667479704d344120 at byte 0
667479704d344120 at byte 4
PRONOMfmt/199
WikidataQ336316
Library of Congressfdd000037fdd000155

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Open it

And 32 more in the JSON record.

Convert it

ToWithFidelityCommand and losses
FLAC (Free Lossless Audio Codec) 1.2.1FFmpegLosslessffmpeg -i in.mp4 out.flac
Lossless for decoded audio; a lossy source stays as degraded as it was. WAV may reduce bit depth or drop metadata.
Waveform AudioFFmpegLosslessffmpeg -i in.mp4 out.wav
Lossless for decoded audio; a lossy source stays as degraded as it was. WAV may reduce bit depth or drop metadata.
Matroska 1-4FFmpegLossyffmpeg -i in.mp4 out.mkv
Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
MPEG 1/2 Audio Layer 3FFmpegLossyffmpeg -i in.mp4 out.mp3
Lossy re-encoding.
OggFFmpegLossyffmpeg -i in.mp4 out.ogg
Lossy re-encoding.
WebMFFmpegLossyffmpeg -i in.mp4 out.webm
Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
0

Sources

From Converters (FFmpeg, ImageMagick, Pandoc, LibreOffice), Just Solve the File Format Problem (File Formats Wiki), Wikidata. Updated 2026-10-24.

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