Audio converter

Load a local audio file, choose the output and channel mode, then convert. Processing stays in your browser. A completed conversion creates a download link; nothing downloads automatically. Changing the file or settings discards the previous output. Cancel discards the pending result; Reset also clears the source.

Supported PCM WAV and AIFF sources retain their sample rate and frame count. Other decodable inputs use the browser decoder at 48 kHz; supported codecs vary by browser. The source information shows the actual decoded rate, channel count and frames. A frame contains one sample per channel. FLAC and other browser-supported formats may be inputs; there is no FLAC output encoder.

Keep preserves the channel layout. Mono mix averages stereo as (L + R) / 2, so opposite channels can cancel. Stereo duplicates a mono channel. Left and Right extract the selected stereo channel; with a mono source both retain that single channel.

WAV and AIFF outputs use PCM16. Samples are rounded and values outside −1…1 are clipped. PCM16 can be repackaged between these containers without changing samples when rate and channels remain unchanged; higher precision inputs lose precision at PCM16. The bitrate control has no effect on these uncompressed formats and is hidden.

MP3 uses 48 kHz encoding and is lossy. Opus and AAC are offered only when supported by the browser recorder; encoding runs in real time and takes approximately the clip duration. Their output rate and exact duration are browser-dependent, and the chosen bitrate is a request, not a size guarantee. Lossy encoders may add delay or padding; repeated lossy conversion can reduce quality. Recorder outputs include short silence margins before and after the clip so its final audio packet is retained. Use WAV or AIFF for sample-exact duration.

Limits: 64 MiB input files, 32 million decoded sample values, and at most two channels. RF64 and metadata preservation are not supported. Files and converted audio are not retained across page reloads.

MP3 uses the bundled lamejs/LAME encoder; see its license. Format references: AIFF specification and Web Audio decoding.

MP3 progress follows encoded samples; native recording progress follows elapsed audio time and reaches completion after finalization. Loading and resampling can show an indeterminate bar. Cancel stops the job and discards old output. Format, channel and bitrate preferences are remembered; audio files are never stored in settings.