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Sub-Millisecond Snapping · 8ms Micro-Crossfades

Free Audio and MP3 Cutter Online with Waveform Trimming

Cut, trim, and slice audio files in your browser with sub-pixel zero-crossing accuracy and 8ms anti-click micro-fades. 100% private with instant lossless WAV export.

Free Audio and MP3 Cutter Online with Waveform Trimming

Ready for a local audio or video file

✨ Hover any tool icon to see what it does · Click to launch

Export Formats & Application Guide

AutoSilenceCut provides multi-option categorized exports tailored for video creators, podcasters, sound designers, and post-production editors.

🎬 Video Formats

Trimmed Video (.webm / .mp4)

Rendered cut video with silent gaps stripped out directly in the browser.

YouTube, Social, Quick Share
Extracted Master Audio (.wav)

Lossless 16-bit uncompressed audio track extracted from your video file.

DAW audio finishing

🎵 Lossless Audio & Takes

Master Audio (16-bit Lossless .wav)

Uncompressed broadcast-grade audio with 8ms anti-click micro-fades and True-Peak limiting.

Podcasts, Voiceovers, Mastering
Compressed Audio (.webm / .mp3)

Lightweight compressed file for fast messaging, email, or draft reviews.

Preview & Fast Sharing
Split Takes to ZIP (.zip)

Bundles individual WAV slices for every speech segment plus a manifest CSV.

Sample Packs, Voice Banks, ML

🎞️ NLE & DAW Project Timelines

Adobe Premiere / DaVinci Resolve (.edl)

CMX 3600 standard edit decision list with frame-accurate timeline cuts.

Premiere Pro, DaVinci Resolve
Final Cut Pro XML (.fcpxml)

Modern XML sequence exchange format for Final Cut Pro and DaVinci Resolve.

Final Cut Pro, DaVinci Resolve
Audacity / Reaper Labels (.txt)

Tab-delimited text file for instant label track import.

Audacity, Cockos Reaper
CSV Edit Ledger (.csv)

RFC-compliant spreadsheet table with exact start/end timestamps and cut durations.

Excel, Google Sheets, Auditing

📝 Subtitles & Metadata

WebVTT Subtitles (.vtt)

W3C standard WebVTT subtitle track re-synchronized with edited speech timing.

HTML5 Video, YouTube, Vimeo
SubRip Subtitles (.srt)

Universal SubRip subtitle file with sequentially numbered and re-timed dialogue cues.

VLC, Social Media, Captions
Show Notes & Summary (.md)

Structured Markdown notes with episode overview, key takeaways, and timestamped chapters.

Podcast Hosts, Blog Posts, Descriptions
Edit Evidence Manifest (.json)

Machine-readable JSON audit manifest with a CRC-32 source checksum, sync diagnosis, and decision items.

Compliance, Archive, Pipelines

Keyboard Shortcuts

Play / Pause
Space
Jump Back 2s
J
Pause
K
Jump Forward 2s
L
Cut Selected Silence
Del / Backspace / D
Keep Selected Pause
R / U
Cycle Pauses
↑ / ↓ / ← / →
Undo / Redo
⌘Z / ⇧⌘Z

Arrange & Merge Clips

Drag clips to arrange the sequence before trimming silences

Select or drop additional video/audio clips to append
No clips added yet. Add multiple videos or audio files to arrange and merge them.
0 clips·00:00.0 Total
100% Client-Side · Zero Server Uploads

Dual-System Audio/Video Sync

Align camera scratch video with separately recorded high-quality external microphone audio. Diagnoses time offset ($\Delta t$) and linear crystal drift ($\alpha$ PPM) 100% locally.

Primary video or reference audio track with camera mic.

High-fidelity external recording (Zoom, Tascam, Rode, lavalier).

Zero cloud uploads · 100% Client-Side

Start fresh with a new file?

Your current edits and audio buffer will be cleared from memory.

100% browser-local processing · No files uploaded to any server

Acoustic Engineering Guide · Architecture

How this tool works in browser memory

How this tool decodes, analyzes, and masters your dialogue locally with zero cloud latency.

01Phase 01

HiDPI Waveform Boundary Selection

Drag start and end playhead boundaries across high-density RMS energy bars with sub-millisecond timeline zoom precision.

02Phase 02

Snap to Speech Alignment

Automated energy scanner detects the first and last spoken syllables, instantly trimming awkward dead air at recording edges.

03Phase 03

Equal-Power Micro-Crossfade

Applies 8ms cosine crossfades at slice boundaries to eliminate pop and click artifacts caused by DC offset discontinuities.

Connected finishing workflows

Explore companion utilities for dialogue cleanup, speech pacing, and mastering.

Audio Splitter by Silence

Split long voice recordings into separate takes.

Open tool→

Silence Remover

Automatically trim quiet pauses throughout longer recordings.

Open tool→

NLE & DAW Exporter

Export cut markers to Audacity label tracks and CMX 3600 EDL.

Open tool→
Audio Standards & Research

Engineering guides & deep-dive workflows

Explore the acoustic principles, ITU-R loudness standards, and pacing techniques behind this tool.

Browse All 58 Guides
Audio Cutting7 min read

How to Trim Audio Files Accurately at Zero-Crossings Without Clicks

The physics of zero-crossing splices and 8ms equal-power crossfades: how to cut dialogue tracks cleanly without abrupt voltage step artifacts.

Read engineering guide→
WAV vs MP36 min read

WAV vs MP3 for Editing Voice: When to Choose Each Format

A technical deep-dive into codec generation loss: why you must keep your master timeline in PCM WAV and only compress to MP3 for final distribution.

Read engineering guide→
Free Audio Editor7 min read

Free Audio Editor for Voice: How to Choose a Safe, Focused Workflow

A 5-point evaluation framework for voice tools: local processing privacy, reversible edits, dialogue-specific pacing controls, and uncompressed export.

Read engineering guide→

Frequently Asked Questions

Common Questions & Technical Clarifications

How does AutoSilenceCut prevent click artifacts when cutting audio?+

Whenever an audio segment is cut or joined, AutoSilenceCut automatically computes an 8ms equal-power linear micro-crossfade across boundary zero-crossings, ensuring silent transitions without audible pops.

What is Snap to Speech boundary trimming?+

Snap to Speech automatically identifies where speech begins and ends, placing trim markers with a calibrated 0.15s safety cushion so you do not have to manually hunt for quiet edges.

Does cutting audio online reduce audio quality?+

No. Unlike cloud cutters that re-encode into lossy 128k or 192k MP3, AutoSilenceCut renders directly to pristine uncompressed 16-bit PCM RIFF WAV format.

Can I undo mistakes while trimming audio?+

Yes. AutoSilenceCut maintains a 50-step deep state history stack accessible via Cmd+Z (undo) and Cmd+Shift+Z (redo).

Are my audio files uploaded to any server?+

No. All slicing and file rendering happen entirely inside your browser sandbox. Zero bytes are uploaded.