Video Converter

Free browser-based Video Converter to change video format without uploading files to ToolsLibrary servers. Upload one video (up to 100 MB), preview it, choose MP4 (H.264 + AAC) or WebM output, pick Original, 720p, or 480p presets, adjust quality, and download the converted file. Processing runs locally with ffmpeg.wasm — speed depends on file size, resolution, and your device.

How to Use the Video Converter

Upload one video, choose MP4 or WebM output with a resolution preset and quality, convert locally with ffmpeg.wasm, then preview and download.

  1. Upload one video file (MP4, MOV, WEBM, MKV, or AVI) up to 100 MB.
  2. Review the preview, file size, duration, and resolution.
  3. Choose output format (MP4 or WebM), preset (Original, 720p, or 480p), and quality.
  4. Select Convert Video and wait for progress to finish — use Cancel if needed.
  5. Preview the result, compare file sizes, and Download. Use Convert Another to start over.

Methodology & WebAssembly video transcoding

In-browser video transcoding utilizes WebAssembly-compiled multimedia libraries (FFmpeg.wasm). The engine demuxes container formats (MP4, WebM, MKV, MOV), decodes video bitstreams (H.264, VP9, AV1), and re-encodes frames using target resolution and bitrate parameters.

All video data remains in browser memory; no video clips are uploaded to cloud servers, ensuring complete privacy for personal and corporate recordings.

Worked video transcoding example

  • Input video: 45-second screen recording in MKV format (1080p, 65 MB).
  • Target export: MP4 container with H.264 video codec and AAC audio at 720p resolution.
  • Transcoding process: WebAssembly FFmpeg decodes frames, rescales to 1280 × 720, and encodes with Constant Rate Factor (CRF 23).
  • Output: Universal MP4 video file (12.4 MB) playable on all modern mobile phones, web browsers, and presentation software.

Output and presets

  • MP4 output uses H.264 video and AAC audio for broad compatibility.
  • WebM is available when you need a web-friendly alternative.
  • Original / 720p / 480p control target resolution; lower presets help on mobile or for smaller downloads.

Privacy

Video is processed locally with ffmpeg.wasm. Files are not uploaded to ToolsLibrary servers. Converter history, if enabled, stores filenames and setting metadata only — never video content.

Limitations

One file up to 100 MB. Support depends on the browser FFmpeg WASM build decoding the source codec — unsupported codecs return a clear error. Transcoding is lossy; quality never exceeds the source. Large or high-resolution files may be slow or fail on low-memory devices. This is a format converter, not a full video editor (no trim/crop/filters beyond the listed presets).

FAQ

What is a video converter?

A video converter changes a video file from one container/format to another — for example MOV to MP4 or WEBM to MP4. This Video Converter runs in your browser and downloads a new file when conversion finishes.

Can I convert MOV to MP4?

Yes. Upload a .mov file, choose MP4 as the output format, select a preset and quality, then Convert Video. If the source codec is supported by the browser FFmpeg build, you can download an MP4 file.

Can I convert WebM to MP4?

Yes. WebM is a supported input format. Select MP4 output to convert WebM to MP4 locally in your browser.

Can I convert MKV or AVI to MP4?

Yes for common MP4, MOV, WEBM, MKV, and AVI uploads when the selected FFmpeg WASM build can decode the source. Unsupported codecs show a clear conversion error instead of a broken download.

Is my video uploaded to a server?

No. Your video is processed in your browser with ffmpeg.wasm and is not uploaded to ToolsLibrary servers for conversion.

What is the maximum video size?

One video up to 100 MB. Larger files are rejected before FFmpeg loads. Admin media settings may adjust this limit.

How long does conversion take?

It depends on file size, resolution, preset, output format, and your device CPU. Short clips may finish in seconds; longer or high-resolution videos can take several minutes — especially on mobile.

Can I use the converter on mobile?

Yes on supported mobile browsers, but conversion may be slow or fail on low-memory devices. Keep files small and use 480p when needed.

Is the converted video watermarked?

No. ToolsLibrary does not add a watermark. Output is a direct transcode/remux based on your settings.

Which output formats are supported?

MP4 and WebM are supported outputs. MP4 uses H.264 video and AAC audio. WebM uses VP9 and Opus when supported by the WASM build.

What resolution presets are available?

Original keeps the source dimensions when possible. 720p and 480p scale the output down for smaller files or weaker devices. Quality controls affect encoding strength within the chosen format.

How is this different from Media Converter?

Video Converter focuses on MP4 or WebM output with Original / 720p / 480p presets and quality controls. Media Converter targets container swaps across MP4, MOV, MKV, AVI, and WebM without resolution presets.