How to mute a section of video audio in your browser
- Step 1Drop your video onto the tool — Open the audio region muter and drag the clip in. Processing runs in your browser via FFmpeg.wasm — the file is never uploaded. MP4, MOV, MKV, WebM, AVI, M4V, and TS are all accepted; you always get an MP4 back.
- Step 2Find the exact in/out times — Scrub your clip in any player and note the start and end of the audio you want gone in seconds. Decimals are fine — Start and End are rounded to three places (e.g.
14.250), so you can be frame-accurate to the millisecond. - Step 3Set Start (s) — Type the start of the region into the Start (s) field. It accepts 0 up to the clip duration. This becomes the lower bound of FFmpeg's
between(t, start, end)window. - Step 4Set End (s) — Type the end into End (s). It must be strictly greater than Start or the tool stops with End time must be after start time. The field is capped at the detected clip duration.
- Step 5Run the mute — The tool runs
volume=enable='between(t,START,END)':volume=0, copies the video stream with-c:v copy, and re-encodes the audio to AAC 192k. The picture is untouched; only the audio inside your window goes silent. - Step 6Download and verify — Play the result with headphones across the boundary you set. The cut to silence is hard (no fade). If you have more than one section to handle, feed this MP4 back in and run another pass.
The only two controls (verified against the tool UI)
The options panel for this tool has exactly two numeric fields. There is no beep/tone option, no fade, no waveform scrubber, and no multi-region list — every claim here is checked against the actual client component.
| Control | What it is | Range | Default |
|---|---|---|---|
| Start (s) | Start of the mute region in seconds. Passed to FFmpeg as the lower bound of between(t, start, end). Decimals allowed (rounded to 3 places, e.g. 12.480) | 0 to clip duration | 0 |
| End (s) | End of the mute region in seconds. Upper bound of the between() expression. Must be greater than Start or the tool stops with *End time must be after start time* | 0 to clip duration | 0 |
| Region count | One region per pass. The tool applies a single between(t, start, end) window. To silence several separate sections, run the tool once per section (the output of one pass is the input to the next) | 1 | 1 |
| Replacement | Silence only — the region's volume is set to 0. There is no beep, tone, hum, or audio substitution. The registry note is explicit: silence is the default to avoid copyright on common beep sounds | fixed | silence |
What actually happens to your file
Grounded in the FFmpeg command the tool runs. The video stream is copied bit-for-bit; only the audio is touched. AAC 192k is transparent for typical speech and music, but it is still a transcode of the full track.
| Stage | FFmpeg behaviour | Effect on your file |
|---|---|---|
| Video stream | -c:v copy — the video is stream-copied, never decoded or re-encoded | Zero quality loss on the picture. No generation loss, no re-compression artefacts, frame-identical to the source |
| Audio filter | -af volume=enable='between(t,START,END)':volume=0 — audio plays at full volume everywhere except the region, where volume drops to 0 | Hard silence inside the region; original audio everywhere else |
| Audio re-encode | -c:a aac -b:a 192k — the entire audio track is re-encoded to AAC at 192 kbps, not stream-copied | One transcode pass on the whole track. AAC 192k is transparent for speech/most music, but it is a re-encode, not a copy |
| Container | Output is always written as out_*.mp4 | You always get an .mp4 back, whatever container you fed in (MOV, MKV, WebM, AVI, M4V, TS) |
| Where it runs | FFmpeg.wasm inside your browser tab — no upload | The file never leaves your device. Nothing is sent to a server |
File-size and batch limits by plan
Video tools are gated by file size and how many files you can queue, not by duration — there is no minutes cap. Numbers from the live tier table.
| Plan | Max file size | Files per batch |
|---|---|---|
| Free | 1 GB | 1 |
| Pro | 10 GB | 5 |
| Pro-media | 100 GB | 50 |
| Developer | 100 GB | unlimited |
Cookbook
Concrete Start/End setups for the most common one-region mutes. Times are in seconds; decimals are allowed.
Mute a 6-second stretch in the middle
A phone rang from 00:32 to 00:38. Set Start to 32 and End to 38; everything else plays at full volume.
Start (s): 32 End (s): 38 FFmpeg runs: -af volume=enable='between(t,32.000,38.000)':volume=0 -c:v copy -c:a aac -b:a 192k out.mp4 Result: silence from 0:32 to 0:38, picture untouched.
Frame-accurate, sub-second window
A single muttered word lands between 1:14.25 and 1:14.90. Decimals give you a tight window without clipping surrounding speech.
Start (s): 74.25 End (s): 74.90 Mutes a 0.65 s window only. Surrounding dialogue stays at full volume.
Two separate sections, two passes
The tool mutes one window per pass. Mute the first, download, feed the MP4 back in, mute the second. The video is copied each time, so nothing degrades.
Pass 1 -> Start 10 End 14 (download out1.mp4)
Pass 2 -> load out1.mp4
Start 41 End 45 (download out2.mp4)
out2.mp4 has both windows silent, picture frame-identical.Silence from a point to the end of the clip
To mute everything after 2:00 on a 2:30 clip, set End past the real end — the filter simply runs out of audio at the true end.
Clip duration: 150 s Start (s): 120 End (s): 150 (the UI caps End at clip duration) Silence from 2:00 to the end; first two minutes untouched.
MOV from a phone, MP4 out
An iPhone .mov works fine — the tool reads MOV and writes MP4. The video stream is copied across containers; only the audio is re-encoded.
Input: clip.mov (H.264 + AAC)
Start (s): 5 End (s): 9
Output: out.mp4 (same video stream, AAC 192k audio,
silence from 0:05 to 0:09)Edge cases and what actually happens
End is less than or equal to Start
RejectedIf End is the same as or earlier than Start, the tool stops immediately with *End time must be after start time. Set both Start and End in the options panel.* Set End to a value strictly greater than Start. A common cause is leaving both at the default 0.
Region runs past the end of the clip
By designThe between(t, start, end) expression simply has no frames to act on past the real end of the audio, so an End value larger than the clip duration silences from Start to the end of the audio and stops. The UI also caps the End field at the detected clip duration, so you normally cannot overshoot.
Audio gets re-encoded even outside the region
ExpectedThe command runs -c:a aac -b:a 192k, which re-encodes the whole audio track, not just the muted window. AAC at 192 kbps is transparent for speech and most music, but if you need a true stream-copy of the untouched audio, this tool is not the right choice — it always does one audio transcode.
Output is MP4 even though you uploaded MOV/MKV/WebM
By designThe tool always writes out_*.mp4. If you need the original container back (for example MKV with multiple tracks), this tool will not preserve it. Use it for the MP4 deliverable, or mute first then remux elsewhere.
Several separate sections to mute
By designEach pass mutes one window. For multiple non-adjacent sections, run the tool repeatedly: mute section 1, download, feed that MP4 back in, mute section 2, and so on. The video is stream-copied each time so the picture never degrades across passes.
You want a beep instead of silence
Not supportedThere is no beep, tone, or audio-replacement control — the region is set to volume 0 (pure silence). The registry note states silence is deliberate to avoid copyright on common beep sounds. If a hard cut to silence is acceptable, this tool is correct; otherwise add a tone in a dedicated audio editor after export.
Clip has no audio track
No effectWith no audio stream the volume filter has nothing to operate on. You will get an MP4 back, but nothing is muted. Confirm the source actually carries audio first — you can check with the audio-track-extractor.
Multiple audio tracks (e.g. commentary + original)
CaveatThe default FFmpeg audio mapping in this single-filter command targets the primary audio stream. Secondary tracks (alternate language, commentary) are not separately addressed by this tool. For multi-track files, split or pre-process the tracks with the audio-track-extractor before muting.
Very large file on the Free plan
BlockedFree caps a single video at 1 GB. A 1080p hour-long export can exceed that. Pro lifts the cap to 10 GB and Pro-media to 100 GB. Because the video is stream-copied, processing is fast even on large files — the bottleneck is the size cap, not duration.
Variable-frame-rate phone footage
SupportedBecause the video is copied rather than re-encoded, VFR footage from phones and screen recorders passes through untouched. The mute window is keyed to playback time t in seconds, so the silence lands at the same wall-clock position regardless of frame timing.
Frequently asked questions
Does muting a section lower the video quality?
No. The video stream is copied with -c:v copy — it is never decoded or re-encoded, so the picture is frame-identical to your source. Only the audio is re-encoded (to AAC 192k).
Can I mute more than one section at once?
Not in a single pass — the tool applies one between(t, start, end) window. For several sections, run it once per section, feeding each output back in. Because the video is copied, repeated passes don't degrade the picture.
Can I add a beep instead of silence?
No. The region is set to volume 0 (pure silence). There is no beep or tone option; the registry note says silence is deliberate to avoid copyright on common beep sounds. If you need a censor beep, add it in an audio editor after export.
Is my video uploaded anywhere?
No. FFmpeg.wasm runs entirely in your browser tab. The file never leaves your device — nothing is sent to a server.
What output format do I get?
Always MP4 (out_*.mp4), regardless of whether you uploaded MP4, MOV, MKV, WebM, AVI, M4V, or TS.
Why is the audio re-encoded if I'm only muting part of it?
The command runs -c:a aac -b:a 192k, which re-encodes the whole audio track in one pass. AAC 192k is transparent for speech and most music, but it is a transcode, not a stream-copy.
Can I use decimals for the times?
Yes. Start and End accept decimals and are rounded to three places (e.g. 14.250), so you can place silence to the millisecond.
What happens if I set End before Start?
The tool stops with End time must be after start time. Set both Start and End in the options panel. Make End strictly greater than Start.
How large a file can I process?
Free handles up to 1 GB per file; Pro 10 GB; Pro-media and Developer 100 GB. There is no minutes cap — limits are by file size and batch count.
Does it remove the audio or just silence it?
It silences the region (volume 0) — the audio track still exists, it's just inaudible in that window. To strip an audio track entirely, use the audio-track-extractor workflow instead.
Will the silence fade in or cut hard?
It's a hard cut to silence at both edges — there is no fade or crossfade control in this tool.
What if I want to keep the original container, like MKV?
This tool always outputs MP4. If you specifically need the source container back, mute here for an MP4 deliverable, then remux separately; container preservation isn't part of this tool.
Privacy first
Every JAD Video tool runs entirely in your browser via WebCodecs and FFmpeg (WebAssembly). Your video files never leave your device — verified by zero outbound network requests during processing.