Audio Trimmer

No. With stream-copy the audio bytes are copied directly from the source into the output, with no re-encoding. The trimmed section is sample-perfect identical to the matching range in the original file. The only minor caveat is that the cut snaps to the nearest codec keyframe (~26 ms for MP3) which is well below human perception.

Not in one pass with this tool. Run the trimmer once per section you want to keep, downloading each piece. To stitch them together afterwards use a separate audio joiner. We may add multi-section trimming as a future feature.

Stream-copy requires the output container to match the input codec. An MP3 input becomes an MP3 output, a WAV input becomes a WAV output, and so on. To convert format and trim in one step use the audio converter tool with start/end parameters - it does both but re-encodes the audio.

500 MB per upload. That covers roughly 10 hours of stereo CD-quality WAV, or 100+ hours of typical MP3. If you need more either trim down a copy first locally or use FFmpeg directly: `ffmpeg -ss START -to END -i input.mp3 -c copy output.mp3`.

The most common cause is a non-audio file (a video without audio extraction, or a broken file). Make sure the file is a real audio format (MP3, WAV, M4A, OGG, FLAC) and that your browser plays it in the preview before pressing Trim. If the preview duration shows 0:00 the file metadata is unreadable and the trimmer cannot determine valid bounds.

Near-instant for stream-copy. Even a 4-hour audiobook trims in seconds because no re-encoding happens. Upload time dominates total wait.

Files travel over HTTPS to api.zeroutil.com (EU server). FFmpeg processes them locally on the server, returns a signed download URL, and both input and trimmed output are auto-deleted after 15 minutes. We do not log content, do not transcribe audio, and do not retain anything beyond the deletion window.