Mix Audio into Video – Overlay Music & Narration

Overlay music, narration, or sound effects on top of a video’s existing sound — mixed entirely in your browser. Free audio-video mixer on ByteKit.

More Video & Audio Tools

Video Trimmer & Muter — Trim a clip by start/end time or strip the audio track — processed on your device with FFmpeg WebAssembly, no upload.
Video to Audio Converter (Extract MP3) — Extract the audio track from any video as MP3, WAV, M4A, OGG, or FLAC — converted on your device with FFmpeg WebAssembly, no upload.
Audio Cutter & Joiner (MP3 Splitter) — Cut a section out of an audio file or merge multiple tracks into one MP3, WAV, or M4A — processed on your device, no upload.
Video Joiner (Merge Clips) — Combine multiple video clips into one file — fast stream-copy for same-source clips or re-encode for mixed formats, all in your browser.
Video to GIF Converter — Turn a video clip into a high-quality animated GIF — pick the section, size, and frame rate; converted on your device, no upload.
Images to GIF Maker — Turn a batch of images into one animated GIF — drag to reorder frames, set the speed, size, and looping. Mixed sizes are normalized automatically. Encoded on your device, never uploaded.
Subtitle Burner — Add and time captions, or import an .srt, then hard-burn them onto a video — font, color, outline, and position controls. Rendered on your device with FFmpeg, exports MP4.
Audiogram Maker — Turn an audio clip + a background image or color into a waveform video for feeds — square, portrait, story, or landscape. Rendered on your device with FFmpeg, exports MP4.