Audio formats and converters

Format reference

MP3 (MPEG-1 Audio Layer III)

MP3 throws away sound the ear is unlikely to notice, using a psychoacoustic model, so a song shrinks to roughly a tenth of its CD size. Best for: sharing, podcasts, car stereos, anything that must just play. Plays on: Everywhere: every phone, browser, car and media player made in the last 25 years.

WAV (Waveform Audio File Format)

WAV stores raw PCM samples with no compression at all. What you save is exactly what the editor sees, which is why studios and editors use it. Best for: editing, mastering, importing into DAWs and video editors. Plays on: Every desktop OS, most phones and all audio software.

FLAC (Free Lossless Audio Codec)

FLAC compresses audio like a ZIP file compresses text: the file gets 40–60% smaller, and every sample comes back bit-for-bit identical on playback. Best for: archiving CDs and masters, hi-fi listening libraries. Plays on: Android, Windows 10+, macOS and iOS 11+ (Files app), VLC, most hi-fi players.

M4A (MPEG-4 Audio)

M4A is an MP4 file with only an audio track, usually AAC. It is what iPhone Voice Memos, Apple Music downloads and many screen recorders produce. Best for: Apple devices, better quality than MP3 at the same size. Plays on: iPhone, Mac, Android, Windows 10+, modern browsers.

AAC (Advanced Audio Coding (raw ADTS stream))

A .aac file is a bare AAC stream without the MP4 wrapper. AAC was designed as MP3’s successor and sounds better at the same bitrate. Best for: broadcast and streaming tools that ask for raw AAC. Plays on: Most phones and players; some older car stereos only accept MP3.

OGG (Ogg Vorbis)

Ogg Vorbis is an open, patent-free lossy codec. Games, Android notification sounds and many Linux apps use it. Best for: games, Android sounds, open-source projects. Plays on: Android, Chrome, Firefox, VLC; not natively on older iPhones.

OPUS (Opus in an Ogg container)

Opus is the codec behind WhatsApp voice notes, Discord and WebRTC calls. It is the most efficient lossy codec here, especially for speech. Best for: voice notes, speech at tiny sizes, web audio. Plays on: Chrome, Firefox, Android, VLC, iOS 17+; older apps may refuse it.

M4R (iPhone ringtone (AAC))

M4R is an M4A file with a different extension. iPhone only accepts it as a ringtone when it is 40 seconds or shorter. Best for: custom iPhone ringtones and text tones. Plays on: iPhone (via Finder, iTunes or GarageBand).

MP4 (MPEG-4 Part 14 video)

MP4 is a container that holds a video track, an audio track (almost always AAC) and metadata. Phones, screen recorders and most downloads use it. Best for: video. Plays on: Everywhere.

MOV (QuickTime movie)

MOV is Apple’s QuickTime container, the default for iPhone camera videos and Mac screen recordings. Its audio is normally AAC. Best for: video. Plays on: Apple devices, most editors.

WEBM (WebM video)

WebM is the open web video container. Browser screen recorders, OBS presets and many online downloads save WebM with Opus audio. Best for: video. Plays on: Browsers, VLC; not QuickTime.

MKV (Matroska video)

MKV (Matroska) can hold almost any codec and several audio tracks. OBS recordings and many films use it. Best for: video. Plays on: VLC, MPV, Plex; few phones play it natively.

WMA (Windows Media Audio)

WMA was Microsoft’s answer to MP3 in the Windows Media Player era. Old CD rips and voice recorders still produce it, but Apple devices and many apps can’t play it. Best for: legacy Windows libraries. Plays on: Windows; not iPhone, Mac or most browsers.

AIFF (Audio Interchange File Format)

AIFF is Apple’s uncompressed format, the Mac equivalent of WAV. Logic, GarageBand exports and CD rips on Macs often use it. Best for: editing on Mac. Plays on: Mac, iPhone, most DAWs; awkward on Android.

AVI (Audio Video Interleave)

AVI is Microsoft’s 1992 video container. Old camcorder clips, screen captures and downloaded films still use it, often with MP3 or AC-3 audio inside. Best for: video. Plays on: Windows, VLC; not iPhone or most browsers.

3GP (3GPP multimedia file)

3GP is the mobile-phone video format of the 2000s. Older Android and feature phones recorded video and voice in it, usually with AMR or AAC audio. Best for: video. Plays on: Android, VLC; patchy elsewhere.

AMR (Adaptive Multi-Rate audio)

AMR is a speech codec designed for mobile calls. Call recorders and older Android voice recorders save .amr files; they are tiny but only cover telephone bandwidth. Best for: call and voice recordings. Plays on: Android; not iPhone, Mac or most browsers.

CAF (Core Audio Format)

CAF is Apple’s audio container. iMessage audio messages, GarageBand loops and some iOS apps save .caf files, which most non-Apple software won’t open. Best for: Apple apps and audio messages. Plays on: Mac and iPhone; rarely elsewhere.