Support & troubleshooting

This page offers suggestions on how to get the results you expect from Cloud Speech-to-Text, and what to do if you need support to help you get the answers you need.


If you have additional need for technical support, you have a number of options listed below.

Ask a question on Stack Overflow

Ask a question about the Speech-to-Text API on Stack Overflow. Please use the tag google-cloud-speech for questions about the Speech-to-Text API. This tag not only receives responses from the Stack Overflow community, but also from Google engineers, who monitor the tag and offer unofficial support.

Discuss the Cloud Speech API and get updates

Join the cloud-speech-discuss Google group to discuss the Speech-to-Text API and receive Speech-to-Text API announcements and updates.

You can also visit the Google Cloud Platform Slack community to discuss Speech-to-Text API and other GCP products. If you haven't already joined, use this form to sign up. For Speech-to-Text API, join the #speech channel.

Get a support package

Google Cloud Platform offers different support packages to meet different needs, such as 24/7 coverage, phone support, and access to a technical support manager. For more information, see Google Cloud Platform Support.


If the results returned by Cloud Speech-to-Text are not what you expected:

  • Check the response for error messages.

  • Note the Quotas & Limits.

  • To improve recognition accuracy, follow the guidelines in Best Practices.

  • If a transcript is not returned (e.g. you receive an empty {} JSON response) and no errors have occurred, it's likely that the audio is not using the proper encoding.

    1. Play the file and listen to the output. Is the audio clear and the speech intelligible?

      To play files, you can use the SoX (Sound eXchange) play command. A few examples based on different audio encodings are shown below.

      FLAC files include a header that indicates the sample rate, encoding type and number of channels, and can be played as follows:

      play audio.flac

      LINEAR16 files do not include a header. To play them you must specify the sample rate, encoding type and number of channels. The LINEAR16 encoding must be 16-bits, signed-integer, little-endian.

      play --channels=1 --bits=16 --rate=16000 --encoding=signed-integer \
      --endian=little audio.raw

      MULAW files also do not include a header and often use a lower sample rate.

      play --channels=1 --rate=8000 --encoding=u-law audio.raw

      Cloud Speech-to-Text service currently supports only one audio channel.

    2. Check that the audio encoding of your data matches the parameters you sent in InitialRecognizeRequest. For example, if your request specified "encoding":"FLAC" and "sampleRateHertz":16000, the audio data parameters listed by the SoX play command should match these parameters, as follows:

      play audio.flac

      should list:

      Encoding: FLAC
      Channels: 1 @ 16-bit
      Sampleratehertz: 16000Hz

      If the SoX listing shows a Sampleratehertz other than 16000Hz, change the "sampleRateHertz" in InitialRecognizeRequest to match. If the Encoding is not FLAC or Channels is not 1 @ 16-bit, you cannot use this file directly, and will need to convert it to a compatible encoding (see next step).

    3. If your audio file is not in FLAC encoding, try converting it to FLAC using SoX, and repeat the steps above to play the file and verify the encoding, sampleRateHertz, and channels. Here are some examples that convert various audio file-formats to FLAC encoding.

      sox audio.wav --channels=1 --bits=16 audio.flac
      sox audio.ogg --channels=1 --bits=16 audio.flac
      sox --channels=1 --bits=16 audio.flac
      sox audio.aiff --channels=1 --bits=16 audio.flac

      To convert a raw file to FLAC, you need to know the audio-encoding of the file. For example, to convert stereo 16-bit signed little-endian at 16000Hz to FLAC:

      sox --channels=2 --bits=16 --rate=16000 --encoding=signed-integer \
      --endian=little audio.raw --channels=1 --bits=16 audio.flac
    4. Run the Quickstart example or one of the Sample Applications with the supplied sample audio file. Once the example is running successfully, replace the sample audio file with your audio file.

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Cloud Speech API Documentation