Free online AAC to WV converter

A media player, editor, or archival workflow may require WavPack when it does not accept AAC. Converting creates a .wv file from the decoded AAC audio, but it cannot restore detail removed during lossy encoding.

What the AAC format is

AAC (Advanced Audio Coding) is a lossy audio codec used for streaming, music downloads, mobile recordings, and video soundtracks. AAC audio is commonly stored in an .m4a container by Apple Music, iTunes, phones, and media applications; an elementary AAC stream normally uses the .aac extension. AAC produces substantially smaller files than uncompressed PCM and usually than lossless formats at comparable perceived quality.

What the WV format is

WV is the filename extension commonly used for WavPack audio. WavPack supports lossless compression, which reduces PCM file size without discarding audio data, and hybrid mode, which combines a lossy WV file with a correction file for lossless reconstruction. It can support multichannel audio, high-resolution samples, tags, and embedded cuesheets when the encoder and application handle those features.

WavPack suits archival copies and editing workflows that support it, but WV is less widely compatible than AAC, MP3, WAV, or FLAC. A lossless WV file made from AAC preserves the decoded AAC result, not the original recording before AAC compression.

Convert with FFmpeg

FFmpeg is a practical desktop option for Windows, macOS, and Linux because it can decode both standalone AAC streams and AAC tracks inside M4A containers, then encode WavPack without an intermediate WAV file.

1. Install a current FFmpeg build and place the source file in an accessible folder.
2. Open Terminal, Command Prompt, or PowerShell in that folder.
3. Run ffmpeg -i input.aac -c:a wavpack output.wv. Replace the filenames as necessary. The same command works with an AAC track in input.m4a.
4. Check the result with ffprobe output.wv or open it in a WavPack-compatible player.

To select the first audio stream and copy supported metadata from an M4A file, use:

ffmpeg -i input.m4a -map 0:a:0 -map_metadata 0 -c:a wavpack output.wv

Use -map 0:a:1 or another stream index when the source contains multiple audio tracks. Metadata, album art, gapless information, and chapter or cue data may not transfer completely because support varies between containers, encoders, and players.

Convert without installing software

You can use the converter on 101convert.com for free: open the AAC-to-WV converter, select an .aac or compatible .m4a file, choose WV, start the conversion, and download the result. Upload only files whose privacy, copyright, and retention requirements are acceptable for a web-based service.

Quality and compatibility limits

• Decoding AAC and encoding the PCM output as lossless WV does not restore frequencies, dynamics, or other information discarded by AAC.
• The WV file will often be larger than the AAC source because it uses lossless compression on already decoded audio.
• Do not convert repeatedly between lossy formats; each lossy re-encoding can add further artifacts.
• For genuine lossless archiving, create WavPack directly from the original WAV, AIFF, or recording session instead of from AAC.
• Test the output in the target application, especially when multichannel audio, high sample rates, album art, cuesheets, or gapless playback are required.