How to convert M4A (AAC/ALAC) to Opus
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Upload your file
Drag and drop a file or click to select one. Keep this page open while the file uploads and converts.
- 2
Convert M4A (AAC/ALAC) to Opus
NexMedia converts M4A (AAC/ALAC) to Opus on its own servers. Processing time depends on the file size and how busy the queue is.
- 3
Download the converted file
When the conversion finishes, the download appears on this page. Your converted file is kept for 2 hours, then deleted.
About M4A (AAC/ALAC)
M4A is an MPEG-4 audio file: the MP4 container holding only audio, usually AAC and sometimes Apple Lossless (ALAC).
Music bought on iTunes, iPhone voice memos and many podcast downloads.
Whether an M4A is lossy or lossless depends on the codec inside, which the file extension does not show.
Convert M4A to Opus online free, no account required — Opus is a modern open lossy codec for speech and music.
Change M4A to Opus without losing quality — convert M4A to Opus free in your browser.
Why won't my car radio or old speaker play my M4A files? The MPEG-4 audio container is newer than MP3, and devices that only decode MP3 cannot read it until it is converted.
About Opus
Opus is an open, royalty-free lossy audio codec standardised by the IETF in 2012 (RFC 6716). It handles both speech and music well, from very low to high bitrates.
Voice and video calls, WhatsApp voice messages, WebRTC, and the audio track of WebM videos.
Opus always decodes at 48 kHz, and some older players and devices do not support it.
Why convert voice recordings to Opus? It stays clear at very low bitrates, so calls and dictation shrink dramatically without becoming hard to understand.
What changes when you convert M4A to Opus
- The audio is decoded and re-encoded as Opus at the default settings, so the result is close to the M4A but not bit-identical.
Settings you can change
Before you convert M4A to Opus, you can adjust: Audio codec, Rate control, Audio bitrate, Quality (VBR), Sample rate, Channels, Normalize loudness, Trim start, Trim duration, and Keep tags.
Limits
Each plan sets a maximum file size and a number of conversions per day, and video and audio files also have a maximum length. Guests can convert files up to 100 megabytes and 5 per day; a free account raises this to 500 megabytes and 25 per day; paid plans go up to 100 gigabytes.
Your converted Opus file is kept for 2 hours, then deleted.
M4A to Opus: questions and answers
Does converting M4A to Opus reduce quality?
The audio is decoded and re-encoded as Opus at the default settings, so the result is close to the M4A but not bit-identical.
What is the difference between M4A and Opus?
M4A is an MPEG-4 audio file, usually holding AAC. Opus is a modern open lossy codec for speech and music.
Can I change the settings when converting M4A to Opus?
Before you convert M4A to Opus, you can adjust: Audio codec, Rate control, Audio bitrate, Quality (VBR), Sample rate, Channels, Normalize loudness, Trim start, Trim duration, and Keep tags.
Do I need an account to convert M4A to Opus?
No. You can convert M4A to Opus without an account; signing in raises the file-size and daily limits.
How long is my converted Opus file kept?
The Opus file you convert from M4A is kept for 2 hours, then deleted automatically.
When I convert M4A to Opus, is the audio re-encoded?
The audio is decoded and re-encoded as Opus at the default settings, so the result is close to the M4A but not bit-identical.
Will converting M4A to Opus change my original file?
No. The conversion reads your M4A and writes a new Opus file, leaving your original M4A file untouched.