Audio converter & waveform trimmer

Fun & miscellaneous

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All processing for this tool happens in your browser. Your input is not sent to a server.

About this tool

Choose supported local audio, select a clip and optionally set its linked sample-peak ceiling and linear fade-in/out. Process the selected samples in a worker, preview the encoded result, then download it without uploading your recording.

Common uses

Make the start and end of a recording less abrupt.
Adjust sample peaks with a shared gain that preserves channel balance.

How to use it

1.Choose a supported local file and wait for decoding and the source waveform.
2.Select the clip, output format and quality; optionally enable normalization with a −24 to 0 dBFS target and set fades in seconds.
3.Process the clip, preview its exported audio and download. Editing options clears the previous result; cancel or clear discards pending work.

Limits and notes

Local input: 80 MiB / 1800s / 1–32 channels; decoded PCM 128 MiB, selected PCM 64 MiB, output 120 MiB. Decode 20s; processing/encoding 60s. Browser decoding may allocate before validation and cannot be forcibly stopped. Cancel discards pending work and closes its context; worker processing is terminated. No upload or playback starts automatically.
One gain preserves the output channel balance. Normalization precedes linear fades; overlapping fades multiply, so the final peak may be lower. MP3/OGG/AAC use the existing stereo mix before processing; WAV keeps every channel. This is sample-peak normalization, not LUFS loudness or true-peak limiting. Lossy encoding and 16-bit rounding can change peaks.
Fade durations are rounded to the nearest sample with at least one sample for a positive fade; endpoints are included. Overlapping fade gains multiply. The peak summary describes processed PCM before encoding, not decoded compressed output. MP3/OGG can add delay, padding or change the tail length; exact exported duration and sample count are not promised.

Frequently asked questions

Which output formats are supported?

MP3, WAV PCM, OGG Vorbis, and AAC are supported. AAC export depends on browser WebCodecs support; input decoding also varies by browser.

Is my audio uploaded?

No. The file is decoded and exported in the browser unless the page explicitly says otherwise.

Is this loudness normalization?

No. It uses one gain from the largest absolute sample across output channels, then applies linear fades. It does not measure LUFS or constrain intersample true peaks; lossy codecs and WAV quantization can change decoded peaks.

What happens to silent and multichannel audio?

Silence stays silent; amplification above 60 dB is refused. WAV retains up to 32 channels. MP3/OGG/AAC first use the existing ordinal stereo mix, then normalize the mixed channels together; no speaker layout is detected.