How to upload a video to Mux with an SRT sidecar using

Trigger: video file uploaded to your S3 bucket


  1. Transcribe: uses speech recognition AI to turn the audio track into a JSON transcript
  2. Subtitle: take the ASR output and convert it to an SRT subtitle file
  3. Upload the video to Mux
  4. Upload the SRT to Mux as a subtitle sidecar file
  5. Webhook: sends the Mux URL for the aforementioned asset to embed in your application

Here's a video walkthrough on how you can create this flow in minutes: