Boost Video Volume Online — Make a Quiet Clip Louder in Your Browser

How it works

Boost MP4, MKV, MOV and more online

A clip arrives too quiet: a phone recording where you held the mic too far, a webinar with the presenter's microphone at half level, a downloaded video whose audio was mixed low, or a family movie where the dialogue is buried under the music. You want it louder, but you do not want to install a video editor or upload a private file to some random website. This tool lets you boost video volume online with nothing but the browser. Drop an .mp4, .mkv, .mov, .avi or an .mp3/.wav, and the audio is lifted with FFmpeg — the same engine desktop software uses, running as WebAssembly on your own machine. It is the fastest way to make a quiet video louder without touching a timeline.

Boost by dB, or normalize — which should you use?

Boosting by dB (a fixed lift)

A decibel (dB) boost multiplies the whole audio signal by a fixed ratio. +6 dB makes the signal about twice as loud to the ear; +10 dB is roughly twice the perceived loudness again. This is the right choice when you know the clip is simply recorded too low and you just want it brought up. The catch: a fixed boost pushes everything up by the same amount, so if a clip was already near maximum level, a big boost makes the waveform clip and sound harsh. That is why the presets stop at +12 dB and why a custom value is capped.

Normalizing to a target loudness

Normalization first measures the clip's actual loudness, then adjusts it to a target level such as -16 LUFS. LUFS (Loudness Units relative to Full Scale) is the broadcast standard behind the consistent volume you hear when skipping between TV channels or YouTube videos. Because normalization measures first, it does not blindly push a loud clip into clipping — it brings quiet clips up and leaves loud clips alone, so a batch of mismatched videos ends up at a uniform, pleasant level. Use Normalize when you are mixing several files together or when you are not sure how much gain is safe.

Why the video is copied losslessly (and why it is fast)

The volume change only affects the audio track, so there is no reason to touch the picture. For video files this tool copies the video stream exactly (-c:v copy) and re-encodes only the audio with the volume or normalization filter. The visual quality is therefore identical to the source — there is no extra generation loss on the image — and the job finishes in a fraction of the time a full re-encode would take. Even a two-hour 4K movie can have its audio boosted in well under a minute, because the CPU only has to process the sound, not every frame. Audio-only files (MP3, WAV, M4A, FLAC and so on) are re-encoded to a 192 kbps MP3 with the same filter, which keeps the result small and universally playable.

Browser booster vs. desktop software

A browser tool and a desktop app solve the same problem under different constraints. The table below shows where each one wins.

Common scenarios for boosting volume

A recording is too quiet to hear

Phone and laptop microphones often record low, especially when the speaker is more than an arm's length away. Drop the clip in, pick +6 or +9 dB, and the dialogue becomes audible on laptop speakers without reaching for a desktop editor.

Mixing clips from different sources

You stitched together footage from a camera, a screen recorder and a phone, and the volumes jump around. Normalize each clip to -16 LUFS so the final edit plays at a steady level instead of forcing the viewer to ride the volume button.

A downloaded or old video has buried dialogue

Some exports mix the voices too low under music or ambient sound. A dB boost lifts the whole track; for a clip where only the dialogue is quiet and the music is already loud, Normalize avoids clipping the music while still raising the average level.

An audio file needs to be louder

WAV narration, a quiet MP3 podcast or an M4A voice memo can all be boosted the same way. The output is an MP3 at 192 kbps, which is plenty for voice and keeps the file light for sharing.

Privacy: your file never leaves your device

Every step happens inside your browser tab. When you open a file, the browser reads it into memory; the FFmpeg engine, loaded as WebAssembly, applies the audio filter on your CPU; and the result is handed back as a download link that points to data still on your machine. No request carrying your video or audio ever reaches our servers, and there is nothing for us to store or delete. The only network traffic is the page itself plus a one-time download of the FFmpeg engine (about 30 MB) the first time you boost a file; after that it is cached by your browser. You can even disconnect from the internet after the page loads and the tool still works.

Frequently asked questions

Supported formats in detail

The booster accepts the same broad set of containers as the player and audio extractor: MP4, M4V, MKV, MOV, AVI, WebM, MPEG-TS/M2TS, FLV, OGV, 3GP and more for video, plus MP3, WAV, M4A, AAC, FLAC, OGG/Opus, CAF and AIFF for audio. Internally it handles common audio codecs (AAC, MP3, AC3, Opus, Vorbis, FLAC, PCM) and applies the volume or loudnorm filter, re-encoding audio to AAC (inside the MP4) or MP3. The output filename keeps the original base name with a -boosted or -normalized suffix so you can tell the two apart. Because the video is stream-copied, the output MP4 plays anywhere an MP4 plays.

Troubleshooting: when the boost does not go as expected

The audio is louder but sounds harsh or distorted

You picked a large dB boost on a clip that was already near maximum level and it clipped. Re-run with a smaller boost, or switch to Normalize mode, which targets a safe peak and prevents clipping automatically.

The clip is still not loud enough

You may have used a small boost (+3 dB) on very quiet material. Try +9 dB, or Normalize to -14 LUFS for a louder, modern result. If the source is extremely low, a single pass can only do so much without pumping artifacts — Normalize handles this best.

The boosted video will not play

The output is a standard H.264 MP4 (or MP3 for audio), which should play anywhere. If your player is unusual, try again; a damaged source stream can occasionally produce a bad frame. For a guaranteed-playable desktop workflow, the Mac converter handles the same job offline.

I need a different output format, not MP4/MP3

This tool emits H.264 MP4 (video) or MP3 (audio) for maximum compatibility. For MOV, MKV, AVI or device-specific outputs, use the Total Video Converter for Mac, which also supports stream-copy remuxing with zero quality loss.

When to use a desktop converter instead

The online booster is ideal for a one-off lift: you have a clip that is too quiet to share, you want to even out a couple of mismatched recordings, or you need a quick louder copy without installing anything. It intentionally keeps things simple — one file, a couple of choices, a download.

If audio work is part of your routine — normalizing a folder of episodes, producing web-ready videos every week, or needing true two-pass peak-limited normalization and exact batch control — a desktop app is the better fit. Total Video Converter for Mac uses your Mac's hardware encoders, handles queues of files, and writes to any format you need, while Total Video Player Pro plays and manages large libraries and can boost or normalize audio on the fly during playback. That is exactly what this free tool is here to point you towards.