Free online OMG to M4A converter

OMG files are usually Sony OpenMG audio files, and many modern players and editors cannot open them directly. Converting them to M4A provides AAC audio in a format supported by phones, media libraries, and editing software.

What the OMG format is

In the Audio category, .omg identifies a Sony OpenMG music file, generally containing ATRAC3 or ATRAC3plus audio. SonicStage and related Sony software created these files for MiniDisc players, Network Walkman devices, and other Sony hardware.

OMG files are most often encountered in old SonicStage music libraries or backups from Sony portable players. Some contain OpenMG DRM, which restricts copying and may prevent direct conversion. The file extension alone does not indicate whether the audio is protected.

What the M4A format is

.m4a is an audio-only MPEG-4 container. It commonly stores AAC audio, although it can also contain ALAC lossless audio.

AAC M4A files usually provide smaller files than uncompressed WAV while retaining good quality at ordinary bitrates. Phones, desktop music applications, streaming libraries, and many audio editors support M4A without additional codecs.

How to convert OMG to M4A

Try the built-in online converter

1. Open the OMG-to-M4A converter on 101convert.com.
2. Select the .omg file and start the conversion.
3. Download the resulting .m4a file and test playback before deleting the original.

This method works only when the uploaded OMG contains decodable, non-DRM audio and the converter supports its particular ATRAC variant. Do not upload copyrighted or confidential recordings unless you have permission to process them.

Use SonicStage when the file is protected

Protected OpenMG files generally cannot be converted directly by FFmpeg or ordinary audio converters. Install and use the original SonicStage installation, if available, to authorize the library and burn the tracks to an audio CD. Then import that CD into a current music application and choose AAC/M4A as the import format.

In Apple Music on macOS, select Music → Settings → Files → Import Settings, choose AAC Encoder, select a bitrate, then use File → Import after inserting the audio CD. In older iTunes versions, the equivalent settings are under Edit → Preferences → General → Import Settings.

Convert an already decoded audio file with FFmpeg

If SonicStage or another compatible tool exports WAV, AIFF, or another FFmpeg-readable file, create an AAC M4A with:

ffmpeg -i input.wav -c:a aac -b:a 192k output.m4a

Use 128k for smaller speech or casual-listening files, or 256k for higher-quality music. FFmpeg normally does not bypass OpenMG encryption, so giving it a protected OMG file will usually produce an unsupported-input or decoding error.

Quality and compatibility limitations

ATRAC-to-AAC conversion is a lossy-to-lossy transcode: the M4A cannot restore information already removed by the original ATRAC encoding. Keep the bitrate at least comparable to the source and avoid repeated conversions.

For archival use, retain the original OMG files and any SonicStage license data. Audio-CD extraction can also introduce a second generation of loss, but it is often the only authorized path for DRM-protected OpenMG material. Check track names, duration, album metadata, and playback after conversion because older SonicStage libraries may not preserve all tags.