Our /video/adaptive Robot

Convert videos to HLS and MPEG-Dash

🤖/video/adaptive encodes videos into HTTP Live Streaming (HLS) and MPEG-Dash supported formats and generates the necessary manifest and playlist files.

This Robot accepts all types of video files and audio files. Do not forget to use Step bundling in your use parameter to make the Robot work on several input files at once.

This Robot is normally used in combination with 🤖/video/encode. We have implemented video and audio encoding presets specifically for MPEG-Dash and HTTP Live Streaming support. These presets are prefixed with "dash/" and "hls/". View a HTTP Live Streaming demo here.

Required CORS settings for MPEG-Dash and HTTP Live Streaming

Playing back MPEG-Dash Manifest or HLS playlist files requires a proper CORS setup on the server-side. The file-serving server should be configured to add the following header fields to responses:

Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET
Access-Control-Allow-Headers: *

If the files are stored in an Amazon S3 Bucket, you can use the following CORS definition to ensure the CORS header fields are set correctly:

[
  {
    "AllowedHeaders": ["*"],
    "AllowedMethods": ["GET"],
    "AllowedOrigins": ["*"],
    "ExposeHeaders": []
  }
]

To set up CORS for your S3 bucket:

  1. Visit https://s3.console.aws.amazon.com/s3/buckets/
  2. Click on your bucket
  3. Click "Permissions"
  4. Edit "Cross-origin resource sharing (CORS)"

Storing Segments and Playlist files

The Robot gives its result files (segments, initialization segments, MPD manifest files and M3U8 playlist files) the right metadata property relative_path, so that you can store them easily using one of our storage Robots.

In the path parameter of the storage Robot of your choice, use the Assembly Variable ${file.meta.relative_path} to store files in the proper paths to make the playlist files work.

Usage example

Implementing HTTP Live Streaming: encode the uploaded video into three versions, then cut them into several segments and generate playlist files containing all the segments:

{
  "steps": {
    ":original": {
      "robot": "/upload/handle"
    },
    "encoded_480p": {
      "robot": "/video/encode",
      "use": ":original",
      "preset": "hls/480p",
      "ffmpeg_stack": "v6.0.0"
    },
    "encoded_720p": {
      "robot": "/video/encode",
      "use": ":original",
      "preset": "hls/720p",
      "ffmpeg_stack": "v6.0.0"
    },
    "encoded_1080p": {
      "robot": "/video/encode",
      "use": ":original",
      "preset": "hls/1080p",
      "ffmpeg_stack": "v6.0.0"
    },
    "hls_bundled": {
      "robot": "/video/adaptive",
      "use": {
        "steps": ["encoded_480p", "encoded_720p", "encoded_1080p"],
        "bundle_steps": true
      },
      "technique": "hls",
      "playlist_name": "my_playlist.m3u8"
    }
  }
}

Parameters

  • use

    String / Array of Strings / Object required

    Specifies which Step(s) to use as input.

    • You can pick any names for Steps except ":original" (reserved for user uploads handled by Transloadit)

    • You can provide several Steps as input with arrays:

      "use": [
  ":original",
  "encoded",
  "resized"
]

    💡 That’s likely all you need to know about use, but you can view Advanced use cases.

  • technique

    String ⋅ default: "dash"

    Determines which streaming technique should be used. Currently supports "dash" for MPEG-Dash and "hls" for HTTP Live Streaming.

  • playlist_name

    String ⋅ default: "playlist.mpd"

    The filename for the generated manifest/playlist file. The default is "playlist.mpd" if your technique is "dash", and "playlist.m3u8" if your technique is "hls".

  • segment_duration

    Integer ⋅ default: 10

    The duration for each segment in seconds.

  • closed_captions

    Boolean ⋅ default: true

    Determines whether you want closed caption support when using the "hls" technique.

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