How to mute audio between specific timestamps in an mp4
- Step 1Convert your timecodes to seconds — Both fields take seconds. Convert mm:ss to seconds first (1:23 → 83). Keep decimals if your timecode has them (1:23.500 → 83.5).
- Step 2Drop the MP4 onto the tool — Open the audio region muter and drag the file in. It runs in your browser via FFmpeg.wasm — no upload. MP4 in, MP4 out (MOV/MKV/WebM/AVI/M4V/TS also accepted, all output MP4).
- Step 3Enter Start (s) — Type the start timestamp in seconds into Start (s). This is the lower bound of the
between()window. - Step 4Enter End (s) — Type the end timestamp into End (s). It must be strictly greater than Start or the tool stops with End time must be after start time.
- Step 5Run the mute — FFmpeg applies
volume=0only between your two timestamps. Everything outside the window plays at full volume; the video stream is copied untouched. - Step 6Verify and chain if needed — Play across both boundaries to confirm. For additional timestamp pairs, feed the output 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 |
Timecode to seconds — quick conversions
Both fields are in seconds. Convert common timecodes first; decimals are allowed.
| Timecode (mm:ss) | Seconds | With decimals |
|---|---|---|
| 0:30 | 30 | 30.000 |
| 1:05 | 65 | 65.000 |
| 2:15.5 | 135.5 | 135.500 |
| 10:00 | 600 | 600.000 |
| 1:02:30 (h:mm:ss) | 3750 | 3750.000 |
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. The 'non-destructive' part applies to the rest of the audio and to the whole video; the audio track itself is transcoded once.
| 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 |
Cookbook
Converting timecodes and chaining windows. Always express times in seconds.
Mute between 1:05 and 1:48
Convert the mm:ss timecodes to seconds, then enter them.
1:05 -> 65 s 1:48 -> 108 s Start (s): 65 End (s): 108 -af volume=enable='between(t,65.000,108.000)':volume=0
Sub-second timestamp pair
A timecode with frames or milliseconds maps to decimal seconds.
2:15.500 -> 135.5 2:16.250 -> 136.25 Start (s): 135.5 End (s): 136.25 (mutes a 0.75 s window)
Three timestamp windows from a transcript
A transcript flagged three spans. One pass per pair; feed the output back in each time.
Pass 1 -> Start 12 End 18 (download out1) Pass 2 -> load out1, Start 95 End 99 (download out2) Pass 3 -> load out2, Start 210 End 217 (download out3) out3 has all three windows silent.
Hour-plus recording
Long timestamps work the same — convert h:mm:ss to seconds.
Mute 1:02:30 to 1:03:00 1:02:30 -> 3750 s 1:03:00 -> 3780 s Start (s): 3750 End (s): 3780
End capped at clip duration
The End field won't exceed the detected duration, so a typo can't push the window past the file.
Clip duration: 600 s Typing End = 9999 is clamped to 600. Silence runs to the true end of the audio.
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
Do I enter timestamps as mm:ss or seconds?
Seconds. Convert mm:ss first (1:05 → 65). Decimals are allowed for sub-second precision (rounded to 3 places).
Is the rest of the audio affected?
No. Only the audio between Start and End is silenced; everything outside the window plays at full volume. (The whole track is re-encoded once to AAC 192k, which is transparent.)
Is the video re-encoded?
No — -c:v copy copies the video stream, so the picture is frame-identical and processing is fast.
Can I mute multiple timestamp ranges?
One pair per pass. For several ranges, feed the output MP4 back in and run again. The copied video doesn't degrade across passes.
What if End is less than 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.
What if I enter an End past the end of the clip?
The End field is capped at the detected clip duration, and the between() expression simply runs out of audio at the true end — silence runs to the end.
Does it accept files other than MP4?
Yes — MOV, MKV, WebM, AVI, M4V, and TS are read too, but the output is always MP4.
Is the MP4 uploaded?
No. FFmpeg.wasm runs in your browser tab; the file never leaves your device.
How precise is the silence boundary?
It's keyed to playback time t, accurate to the decimals you enter (3 places). The cut is hard at both edges — no fade.
Does this shorten the video?
No — it silences audio without changing duration. To remove a segment and close the gap, use the video-splitter or lossless-trimmer.
What's the file-size limit?
Free 1 GB; Pro 10 GB; Pro-media and Developer 100 GB. No minutes cap — limits are by size and batch count.
Does VFR (variable frame rate) footage work?
Yes. Because the video is copied and the window is time-based, VFR phone and screen-recorder footage passes through cleanly.
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.