Fast workflow
Designed to reduce friction with direct upload, quick processing, and one-click export.
Open Video Add Audio, add your file, then choose the target output and run conversion.
This tool is optimized for video processing and works best with mp4, mov, avi, mkv, webm as inputs.
When processing completes, download the result in mp4, mov, avi, mkv, webm and verify quality before sharing.
Video Add Audio is a privacy-first utility for fast video processing. It helps you move from mp4, mov, avi, mkv, webm to mp4, mov, avi, mkv, webm with consistent output quality.
Designed to reduce friction with direct upload, quick processing, and one-click export.
Files are handled in an isolated processing flow with minimal retention and clear user controls.
Outputs are tuned for real use cases across mp4, mov, avi, mkv, webm.
A predictable sequence keeps conversion stable across devices and file sizes.
Video Add Audio accepts mp4, mov, avi, mkv, webm and exports mp4, mov, avi, mkv, webm.
The pipeline is designed for privacy-first processing with clear user control over inputs and outputs.
Use high-quality source files, choose the closest matching target format, and avoid repeated reconversion cycles.
Video Add Audio follows a deterministic conversion flow so results are repeatable and easier to troubleshoot when a file behaves unexpectedly.
Replace or mix audio tracks in a video with a new audio file.
Both the video and audio files are uploaded to ConvertCraft servers where they are combined in a secure FFmpeg pipeline. All source files and the output file are permanently deleted from disk immediately after processing — no data is retained on the server.
This tool muxes an external audio stream into a video container using FFmpeg's stream mapping capabilities. In Replace mode, the original audio stream is dropped entirely and the new audio is encoded to the target codec using -c:a aac (for MP4) or -c:a libopus (for WEBM). In Mix mode, the amix filter blends both audio streams with configurable volume ratios, and the loop flag uses the -stream_loop parameter to tile shorter audio clips to match video duration.
Perfect for adding background music to silent screen recordings, replacing corrupted or poorly captured audio from camera footage, or overlaying voiceover narration onto presentation slides. Also useful for adding intro/outro music to podcast video clips, or syncing a separately recorded audio track back to video when using external microphones.
See the detailed comparison guide or try a related tool: