Transcribe speech in audio or video files

🤖/speech/transcribe transcribes speech in audio or video files.

{
  "steps": {
    "transcribed": {
      "use": ":original",
      "robot": "/speech/transcribe",
      "provider": "aws",
      "format": "json",
      "speaker_labels": true,
      "max_speakers": 3
    }
  }
}

{
  "text": "Hello there. Hi!",
  "words": [
    { "text": "Hello", "startTime": 0, "endTime": 0.5, "speaker": "speaker_1" },
    { "text": "there", "startTime": 0.6, "endTime": 1, "speaker": "speaker_1" },
    { "text": "Hi!", "startTime": 1.2, "endTime": 1.8, "speaker": "speaker_2" }
  ],
  "segments": [
    { "text": "Hello there", "startTime": 0, "endTime": 1, "speaker": "speaker_1" },
    { "text": "Hi!", "startTime": 1.2, "endTime": 1.8, "speaker": "speaker_2" }
  ]
}

Usage example

{
  "steps": {
    "transcribed": {
      "robot": "/speech/transcribe",
      "use": ":original",
      "provider": "replicate",
      "target_language": "french",
      "format": "text"
    }
  }
}

Parameters

• interpolate

  boolean | Record<string, boolean>

  Controls whether Assembly Variables are interpolated for individual instruction fields.

  By default, most Robot instruction fields interpolate Assembly Variables. Set this to false to treat every instruction field as literal text, or set an individual field path to false to treat only that field as literal text. For Robot-specific fields that are literal by default, set this to true or set that field path to true to opt back into interpolation.

  Use field names such as path, or dotted paths such as ffmpeg.vf for nested objects.

• output_meta

  Record<string, boolean> | boolean | Array<string>

  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 images, you can also add "blurhash": true to extract a BlurHash⁠ string — a compact representation of a placeholder for the image, useful for showing a blurred preview while the full image loads.

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

  For videos, you can also add "interlaced": true to detect whether the video is interlaced. This combines the cheap ffprobe field_order flag with a bounded idet sampling pass over the first frames of the source, exposing interlaced, field_order, and a diagnostic interlace_detection object under file.meta. This is computationally expensive and billed accordingly.

  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.

• user_meta

  Record<string, any>(default: {})

  Adds custom metadata to each file emitted by this Robot without modifying the file’s contents.

  The values are merged with any existing user_meta carried by the input file. If both objects contain the same key, this Robot’s value takes precedence. Assembly Variables are supported, for example { "internal_file_id": "${file.id}" }.

• 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.

• ignore_errors

  boolean | Array<meta | execute>(default: [])

  Ignore errors during specific phases of processing.

  Setting this to ["meta"] will cause the Robot to ignore errors during metadata extraction.

  Setting this to ["execute"] will cause the Robot to ignore errors during the main execution phase.

  Setting this to true is equivalent to ["meta", "execute"] and will ignore errors in both phases.

• 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"
      ]
    }
    

  • You can also tag input Steps with as to pass semantic intent to robots:

    {
      "use": [
        {
          "name": ":original",
          "as": "image"
        },
        {
          "name": ":original",
          "as": "mask"
        }
      ]
    }
    

  Tip

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

• provider

  auto | aws | gcp | replicate(default: "auto")

  Chooses the best provider based on your request.

  Set this to "aws", "gcp", or "replicate" to force a specific provider. When set to "auto", Transloadit uses "replicate" by default and uses "aws" when speaker_labels is enabled.

• granularity

  full | list(default: "full")

  Both "full" and "list" currently return the same complete transcription response. "list" remains accepted for backward compatibility.

• format

  json | meta | srt | text | webvtt(default: "json")

  Output format for the transcription.

  • "text" outputs a plain text file that you can store and process.
  • "json" outputs a JSON file containing timestamped words. When speaker_labels is enabled, words can include speaker labels and the JSON can also include grouped segments by speaker.
  • "srt" and "webvtt" output subtitle files of those respective file types, which can be stored separately or used in other encoding Steps.
  • "meta" does not return a file, but stores the data inside Transloadit's file object (under ${file.meta.transcription.text}, ${file.meta.transcription.words}, and, when speaker labels are available, ${file.meta.transcription.segments}) that's passed around between encoding Steps, so that you can use the values to burn the data into videos, filter on them, etc.

• speaker_labels

  boolean(default: false)

  When enabled, Transloadit asks the transcription provider to distinguish different speakers. JSON and meta output can then include speaker labels such as "speaker_1" on individual words, plus grouped segments by speaker. Text, SRT, and WebVTT output behavior is unchanged.

  Speaker labels identify recurring voices, not real person names. Accuracy depends on audio quality, background noise, overlapping speech, and the number of speakers.

• max_speakers

  string | number(default: 10)

  The maximum number of speakers to detect when speaker_labels is enabled.

• source_language

  string(default: "en-US")

  Sets the spoken language for the "aws" and "gcp" providers. The transcription stays in the spoken language; this parameter does not translate speech.

  The language should be specified in the BCP-47⁠ format, such as "en-GB", "de-DE" or "fr-FR". Please also consult the list of supported languages for the gcp provider⁠ and the aws provider⁠.

• target_language

  string

  Sets the spoken language hint for the "replicate" provider. Omit this parameter to detect the spoken language automatically. Set it to the full lowercase English language name, such as "french", when the spoken language is known. Despite its name, this parameter does not translate speech.

  For the "aws" and "gcp" providers, use source_language instead.

Demos

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