# Remove Mains Hum from a Video Kill 50/60 Hz electrical hum and harmonics in a video's audio with tuned notch filters. The picture is untouched and nothing is uploaded. ## Run it - **CLI:** `gizza tool video-audio-hum-remover 'url=https://example.com/input' 'frequency=50' 'harmonics=4' 'q=10'` - **Web:** https://gizza.ai/tools/video-audio-hum-remover/ - **Agents:** machine-readable descriptor (parameters JSON Schema) at https://gizza.ai/tools/video-audio-hum-remover/tool.json ## Inputs - `file` — Video _(file; accept: video/*)_ - `frequency` — Mains frequency _(field)_ - `harmonics` — Harmonics to notch _(field)_ - `q` — Notch narrowness (Q) _(field)_ ## Output - De-hummed video (video) ## Query parameters Open the tool pre-filled and auto-run via URL: - `frequency` — Mains frequency - `harmonics` — Harmonics to notch - `q` — Notch narrowness (Q) - `url` — fetch the input file from a public URL (CORS-permitting) Example: `https://gizza.ai/tools/video-audio-hum-remover/?url=https://example.com/input&frequency=50&harmonics=4&q=10` --- ## Remove electrical hum from a video A steady low buzz under your audio — the classic 50 Hz or 60 Hz **mains hum** picked up from power supplies, ground loops, cheap adapters and fluorescent lights — sits at one fundamental frequency *and* a stack of harmonics above it. This tool drops a **narrow notch filter** on the fundamental and on each harmonic in one pass, pulling the hum comb out while leaving the rest of the audio alone. The picture is **stream-copied** (not re-encoded), so it stays byte-for-byte identical and processing is fast; only the audio is re-encoded. Everything runs in your browser — nothing is uploaded. ### Pick the mains frequency - **50 Hz** — Europe, Asia, Africa, most of Australia. Harmonics land at 100, 150, 200 Hz… - **60 Hz** — North America and most of South America. Harmonics land at 120, 180, 240 Hz… If you don't know, look at where the clip was recorded, or just try both and keep the one where the buzz disappears. ### Harmonics and narrowness - **Harmonics to notch** (0–12) — how many multiples above the fundamental to also filter. Hum is rarely a pure tone; it leaks into 2×, 3×, 4×… the base. The default **4** notches, for 50 Hz, 50 / 100 / 150 / 200 / 250 Hz. Set it to **0** to notch only the fundamental. - **Notch narrowness (Q)** (1–100) — how tight each notch is. A **higher Q** is narrower and removes less of the audio around each hum line (safer for music and voices); a lower Q is wider and more aggressive. **10** is a good general default; **2–10** suits most mains hum, and **30–40** is a good music-safe choice. **Worked example:** a webcam interview with a steady 50 Hz buzz from a nearby power brick. Load `interview.mp4`, leave **Mains frequency** on **50 Hz**, **Harmonics** on `4` and **Q** on `10`. Notches at 50/100/150/200/250 Hz pull the buzz down while the voice stays intact, and you get `interview-dehummed.mp4`. ### Notes and limits - The video stream is copied losslessly; the output keeps the same container (mp4 → mp4, webm → webm). WebM audio is re-encoded to Opus, everything else to AAC. - This is a classic notch chain, not an AI "studio voice" model — it targets *steady* mains hum sitting at fixed frequencies, not broadband hiss or fan noise. For general hiss, use the **Remove Background Noise from a Video** tool. - One setting is applied to the whole clip; there is no per-region control. Trim first if you only want part of the audio processed. - Input and output are each capped at 25 MB (the file is processed in your browser's memory). ### FAQ
Is my video uploaded to a server? No — ffmpeg runs inside your browser tab, so the file never leaves your device.
Should I choose 50 Hz or 60 Hz? Match the electrical grid where the clip was recorded: **50 Hz** for Europe, Asia, Africa and Australia, **60 Hz** for North and South America. If you're not sure, try one, and if the buzz is still there switch to the other.
What are "harmonics" and how many should I notch? Mains hum is never a single pure tone — energy also appears at whole-number multiples of the base frequency (for 50 Hz: 100, 150, 200 Hz…). **Harmonics to notch** filters those too. The default **4** clears the fundamental plus the first four multiples, which handles most hum. Raise it if a higher-pitched buzz survives; set it to **0** to touch only the fundamental.
What does the Q (notch narrowness) control do? Q sets how tight each notch is. A **high Q** (say 30–40) is very narrow, so it removes the hum line with almost no effect on nearby music or voices. A **low Q** (2–10) is wider and more aggressive — better when the hum drifts slightly or is strong, at the cost of thinning the audio around it. **10** is a sensible default.
Will removing hum hurt the video quality? No. Only the audio is changed; the **picture is stream-copied without re-encoding**, so the video quality is identical to the original.
Which video formats can I use, and how big can the file be? Anything ffmpeg can read — mp4, mov, mkv and webm are the common cases. The output keeps the input's container and is named after the original with a `-dehummed` suffix (e.g. `clip.mp4` → `clip-dehummed.mp4`). The input and output are each capped at 25 MB.
## Related tools - [Fit Audio to an Exact Length](https://gizza.ai/tools/audio-fit-to-length/): Make any audio file an exact number of seconds — pad it with silence when it's short or trim it when it's long. Runs in your browser, nothing uploaded. - [Shorten Long Audio Pauses](https://gizza.ai/tools/audio-pause-shortener/): Tighten speech pacing by shortening long silent gaps to a natural pause length in your browser. Nothing is uploaded, free. - [Resample an Audio File](https://gizza.ai/tools/audio-resampler/): Change any audio file's sample rate — 8 kHz voice to 192 kHz studio — with high-quality ffmpeg resampling, right in your browser. Runs locally, nothing is uploaded, free. - [Add Chorus to Audio](https://gizza.ai/tools/chorus/): Add a configurable chorus effect to an audio file in your browser with ffmpeg: voices, delay, depth, rate, decay, and output format controls. - [Set a Video's Audio Bitrate](https://gizza.ai/tools/video-audio-bitrate-set/): Re-encode just a video's audio at your chosen bitrate to shrink an oversized soundtrack while the picture is stream-copied untouched. Runs in-browser; nothing uploaded.