FFreeTool.wang

Video Merger

Normalize and join a small ordered set of decodable clips into one MP4.

Video merger

Runs in one local browser worker. Files are never uploaded.

ffmpeg.wasm · local

Every clip is normalized and re-encoded before concatenation so different codecs, dimensions, frame rates, and audio sample rates can be merged. Inputs must contain audio.

How to use Merge Videos

Clips with different dimensions, frame rates, orientations, and codecs cannot be concatenated reliably as-is. Normalization takes time and can reduce quality.

  1. Choose a small set of clips and drag them into order.
  2. Review duration, orientation, dimensions, and audio on each clip.
  3. Choose a common canvas, frame rate, and padding behavior.
  4. Inspect every join, audio level, and total duration after merge.

Available controls

  • Order and enabled clips
  • Common dimensions and background padding
  • Frame rate and quality
  • Silent-track handling for clips without audio

What it helps with

  • Normalizes clips from different sources
  • Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task.

Compatibility and limits

  • Total size and browser memory make many long clips unsuitable
  • Different clip properties normally require re-encoding
  • No transitions, timeline, multitrack mix, or subtitle editing

Frequently asked questions

Why are there black bars?

Different aspect ratios need padding when the complete frame is preserved.

Why does volume change at a join?

Sources have different levels and sample settings; professional loudness normalization is not included.

Are videos uploaded?

Media is read and transcoded in this browser tab and is not uploaded to FreeTool to perform the task.

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