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A simple MP4 video trimmer using the WebCodecs API ​

Screenshot

sh
npm install media-trimmer
js
import { trim } from 'media-trimmer'

try {
  // The input video must be a `.mp4`/`.mov` file with a video track
  // and the browser must support video encoding with the WebCodecs API
  await trim('video.mp4', {
    start: 2, //    start time in seconds
    end: 10, //     end time in seconds
    mute: false, // ignore the audio track?
  })
} catch (error) {
  alert(error)
}

It also comes with a Web Component UI:

html
<!-- after importing the library, the <media-trimmer> custom element will be defined -->
<media-trimmer id="trimmer" source="video.webm"></media-trimmer>
<button id="export" type="buton">Get trimmed video</button>
<progress id="export-progress" max="1" />

<script type="module">
const trimmer = document.getElementById('trimmer')
const button = document.getElementById('export')
const progress = document.getElementById('export-progress')

// save the trimmed video to a file
button.addEventListener('click', async () => {
  const blob = await trimmer.toBlob()

  const anchor = document.createElement('a')
  const blobUrl = URL.createObjectURL(blob)

  anchor.href = blobUrl
  anchor.target = '_blank'
  anchor.download = 'trimmed.webm'
  anchor.dispatchEvent(new MouseEvent('click'))
  URL.revokeObjectURL(blobUrl)
})

// display the trimming progress
trimmer.addEventListener('progress', (event) => progress.value = event.detail.progress)
<script>

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Roadmap ​

  • Lossless trimming
  • Bitrate/filesize controls
  • Webm support
  • Color profile preservation
  • Increased browser and codec support via LibAVJS-WebCodecs-Polyfill