Data input and output - Amazon Transcribe

Data input and output

Amazon Transcribe takes audio data, either a media file in an Amazon S3 bucket or a media stream, and converts it to text data.

If you're working with media files stored in an Amazon S3 bucket, you're performing batch transcription jobs; if you're working with media streams, you're performing streaming transcriptions. These two processes have different rules and requirements.

Media formats

Supported media types differ between batch transcriptions and streaming transcriptions, though lossless formats are recommended for both. See the following table for details:

Batch

Streaming

Supported formats

  • AMR

  • FLAC

  • MP3

  • MP4

  • Ogg

  • WebM

  • WAV

  • FLAC

  • OPUS-encoded audio in an Ogg container

  • PCM signed 16-bit little-endian audio (note that this does not include WAV)

Recommended formats

  • FLAC

  • WAV with PCM 16-bit encoding

  • FLAC

  • PCM encoding

Sample rates

With batch transcription jobs, you can choose to provide a sample rate, though this parameter is optional. If you do include it in your request, make sure the value you provide matches the actual sample rate in your audio; if you provide a sample rate that doesn't match your audio, your job may fail.

With streaming transcriptions, you must include a sample rate in your request. As with batch transcription jobs, make sure the value you provide matches the actual sample rate in your audio.

Sample rates for low fidelity audio, such as telephone recordings, typically use 8,000 Hz. For high fidelity audio, Amazon Transcribe supports values between 16,000 Hz and 48,000 Hz.

Output

All batch transcripts are stored in Amazon S3 buckets. You can either choose to save your transcript in your own Amazon S3 bucket, or have Amazon Transcribe use a secure default bucket. To learn more about creating and using Amazon S3 buckets, see Working with buckets.

If you want your transcript stored in an Amazon S3 bucket that you own, specify the bucket's URI in your transcription request. Make sure you give Amazon Transcribe write permissions for this bucket prior to starting your batch transcription job. If you specify your own bucket, your transcript remains in that bucket until you remove it.

If you don't specify an Amazon S3 bucket, Amazon Transcribe uses a secure service-managed bucket and provides you with a temporary URI that you can use to download your transcript. Note that temporary URIs are valid for 15 minutes. If you get an AccesDenied error when using the provided URI, run a getTranscriptionJob request to get a new temporary URI for your transcript.

If you opt for a default bucket, your transcript is deleted when your job expires (90 days). So if you want to keep your transcript, you must download it before the expiration date.

Streaming transcripts are returned via the method you're using for your stream (WebSocket or HTTP/2).