Free online OPUS to AT3 converter

What the OPUS format is

OPUS is a modern, open, lossy audio codec designed for speech and music at low latency and efficient bitrates. It is commonly stored in an Ogg container with the .opus extension and is created by web browsers, WebRTC applications, voice software, Audacity, FFmpeg, and recording tools.

OPUS files are common in downloaded voice recordings, browser-based captures, messaging applications, and media converted with FFmpeg. Many older portable players and Sony applications do not decode OPUS directly.

What the AT3 format is

AT3 usually denotes Sony ATRAC3 audio, a proprietary lossy codec used by devices and software from the Sony ecosystem, including some PlayStation Portable and PlayStation 3 workflows. An AT3 file normally contains ATRAC3 audio in a Sony-compatible container or header rather than raw codec data alone.

ATRAC3 can provide predictable playback on compatible Sony hardware and supports device-specific bitrate modes. It is useful when a player, game, or authoring program explicitly requires .at3; it is not a general-purpose replacement for OPUS on modern computers.

How to actually convert OPUS to AT3

The most reliable desktop workflow uses FFmpeg for decoding and software containing Sony's ATRAC3 encoder for the final export.

1. Install FFmpeg and decode the OPUS file to an uncompressed PCM WAV file:

ffmpeg -i input.opus -c:a pcm_s16le -ar 44100 -ac 2 intermediate.wav

Change -ar 44100 or -ac 2 only when the target device requires another sample rate or channel count. The WAV is an intermediate file; it does not improve the original OPUS quality.

2. Open intermediate.wav in a desktop editor or encoder that provides the Sony ATRAC3/AT3 codec, such as a compatible version of Sony Sound Forge with the ATRAC export component installed.
3. Choose File → Save As or File → Export, select the ATRAC3 or AT3 format, and choose the bitrate, sample rate, channel mode, and filename required by the target device.
4. Save the result with the .at3 extension, then test it on the actual player or application. Some Sony workflows require a particular bitrate or folder structure in addition to the extension.

FFmpeg is useful for preparing the WAV, but many FFmpeg builds can decode ATRAC3 without providing a licensed ATRAC3 encoder. If the AT3 option is absent, installing another FFmpeg build usually will not solve the problem; use software with a compatible Sony encoder instead.

For a no-installation option, upload the source and select the target format on the free converter at 101convert.com, then download the generated AT3 file. Verify the output on the intended Sony device because AT3 compatibility depends on codec variant and encoding parameters.

Quality and compatibility limits

OPUS and ATRAC3 are both lossy codecs, so the conversion can introduce additional artifacts, especially in cymbals, speech sibilants, and other high-frequency material. Use the highest bitrate accepted by the target and keep the original OPUS file as the source archive.

Do not rename an OPUS file to .at3; the codec, container metadata, and header must be encoded correctly. An AT3 file made for one Sony application may still fail in another if it uses ATRAC3plus, an unsupported bitrate, an incompatible sample rate, or a different required container structure.