Transloadit

Extract or insert audio artwork

🤖/audio/artwork extracts the embedded cover artwork from audio files and allows you to pipe it into other Steps, for example into /image/resize Steps. It can also insert images into audio files as cover artwork.

For extraction, this Robot uses the image format embedded within the audio file — most often, this is JPEG.

If you need the image in a different format, pipe the result of this Robot into 🤖/image/resize.

The method parameter determines whether to extract or insert.

Usage example

Extract embedded cover artwork from uploaded audio files:

{
  "steps": {
    "artwork_extracted": {
      "robot": "/audio/artwork",
      "use": ":original",
      "ffmpeg_stack": "v6"
    }
  }
}

Parameters

  • output_meta

    Record<string, boolean> | boolean

    Allows you to specify a set of metadata that is more expensive on CPU power to calculate, and thus is disabled by default to keep your Assemblies processing fast.

    For images, you can add "has_transparency": true in this object to extract if the image contains transparent parts and "dominant_colors": true to extract an array of hexadecimal color codes from the image.

    For videos, you can add the "colorspace: true" parameter to extract the colorspace of the output video.

    For audio, you can add "mean_volume": true to get a single value representing the mean average volume of the audio file.

    You can also set this to false to skip metadata extraction and speed up transcoding.

  • result

    boolean (default: false)

    Whether the results of this Step should be present in the Assembly Status JSON

  • queue

    "batch"

    Setting the queue to 'batch', manually downgrades the priority of jobs for this step to avoid consuming Priority job slots for jobs that don't need zero queue waiting times

  • force_accept

    boolean (default: false)
      Force a Robot to accept a file type it would have ignored.
    

    By default Robots ignore files they are not familiar with. 🤖/video/encode, for example, will happily ignore input images.

    With the force_accept parameter set to true you can force Robots to accept all files thrown at them. This will typically lead to errors and should only be used for debugging or combatting edge cases.

  • use

    string | Array<string> | Array<object> | object

    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"
        ]
      }
      
  • ffmpeg

    object

    A parameter object to be passed to FFmpeg. If a preset is used, the options specified are merged on top of the ones from the preset. For available options, see the FFmpeg documentation. Options specified here take precedence over the preset options.

  • ffmpeg_stack

    "v5" | "v6" | "v7" | string (default: "v5.0.0")

    Selects the FFmpeg stack version to use for encoding. These versions reflect real FFmpeg versions. We currently recommend to use "v6.0.0".

  • preset

    Performs conversion using pre-configured settings.

    If you specify your own FFmpeg parameters using the Robot's ffmpeg parameter and you have not specified a preset, then the default mp3 preset is not applied. This is to prevent you from having to override each of the MP3 preset's values manually.

    For a list of audio presets, see audio presets.

  • method

    "extract" | "insert" (default: "extract")

    What should be done with the audio file. A value of "extract" means audio artwork will be extracted. A value of "insert" means the provided image will be inserted as audio artwork.

  • change_format_if_necessary

    boolean (default: false)

    Whether the original file should be transcoded into a new format if there is an issue with the original file.

Demos

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