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Speech to TextBatch Transcription

Input

Learn about the supported input audio formats for the Speechmatics Batch API

This page documents audio inputs for transcription by REST API (a.k.a. Batch SaaS).

Supported File Types​

The following file formats types are supported for transcription by REST API:

  • wav
  • mp3
  • aac
  • ogg
  • mpeg
  • amr
  • m4a
  • mp4
  • flac

The list above is exhaustive - any file format outside the list above is explicitly not supported.

Only files where the type can be determined by data inspection are supported. Raw audio formats where the codec is not embedded in the file cannot be processed in batch mode. This includes files commonly given extensions like ".raw" or ".g729" where the codec is only hinted at in the name.

Fetch URL​

If you store your digital media in cloud storage (for example AWS S3 or Azure Blob Storage) you can also submit a job by providing the URL of the audio file. The configuration uses a fetch_data section, which looks like this:

Configuration example​

{
  "type": "transcription",
  "transcription_config": {
    "language": "en",
    "diarization": "speaker"
  },
  "fetch_data": {
    "url": "${URL}/{FILENAME}"
  }
}

In SaaS, fetch requests made to the URL in fetch_data have user agent set to Speechmatics-API/2.0.

Fetch failure​

If the Speechmatics Batch SaaS is unable to retrieve audio from the specified online location, the job will fail, with a status of rejected, and no transcript will be generated. Users can now retrieve failure information by making a GET /jobs/$JOBID request, and use that to carry out diagnostic information.

If the job has failed, there will be an additional errors element, which will show all failure messages Speechmatics Batch SaaS encountered when carrying out the fetch request. Please note, there can be multiple failure attempts associated with one submitted job, as there is a retry mechanism in place.

{
  "job": {
    "config": {
      "fetch_data": {
        "url": "https://example.com/average-files/punctuation1.mp3"
      },
      "notification_config": [
        {
          "contents": ["jobinfo"],
          "url": "https://example.com/"
        }
      ],
      "transcription_config": {
        "language": "de"
      },
      "type": "transcription"
    },
    "created_at": "2021-07-19T12:55:03.754Z",
    "data_name": "",
    "duration": 0,
    "errors": [
      {
        "message": "unable to fetch audio: http status code 404",
        "timestamp": "2021-07-19T12:55:05.425Z"
      },
      {
        "message": "unable to fetch audio: http status code 404",
        "timestamp": "2021-07-19T12:55:07.649Z"
      },
      {
        "message": "unable to fetch audio: http status code 404",
        "timestamp": "2021-07-19T12:55:17.665Z"
      },
      {
        "message": "unable to fetch audio: http status code 404",
        "timestamp": "2021-07-19T12:55:37.643Z"
      }
    ],
    "id": "a81ko4eqjl",
    "status": "rejected"
  }
}