Guidelines and quotas
Amazon Transcribe has several guidelines to follow in order to achieve optimal results. There are also quotas that may impact your transcriptions; some of these can be increased. Refer to the following sections for details.
Supported AWS Regions
For a list of AWS Regions where Amazon Transcribe is available, see Amazon Transcribe Endpoints and Quotas in the AWS General Reference.
Guidelines
For best results:
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Use a lossless format, such as FLAC or WAV with PCM 16-bit encoding.
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Use a sample rate of 8,000 Hz for low-fidelity audio and 16,000-48,000 Hz for high-fidelity audio.
If you don't need to process all of your transcription jobs concurrently, use Job queueing. This enables Amazon Transcribe to keep track of your transcription jobs and process them when slots are available.
Amazon Transcribe may temporarily store your content to continuously improve the quality
of its analysis models. See the Amazon Transcribe FAQ
Quotas
The following quotas cannot be changed:
| Description | Quota |
|---|---|
| Audio file length | 4:00:00 (four) hours (14,400 seconds) |
| Audio stream duration | 4:00:00 (four) hours (14,400 seconds) |
| Audio file size | 2 GB |
| Audio file size (call analytics) | 500 MB |
| Size of a custom vocabulary | 50 KB |
| Length of a custom vocabulary phrase | 256 characters |
| Size of a vocabulary filter | 50 KB |
| Number of vocabulary filters | 100 |
| Number of channels for channel identification | 2 |
| Number of days job records are retained | 90 |
| Minimum audio file duration | 500 milliseconds (ms) |
You can request a quota increase for the following resources:
| Resource | Default |
|---|---|
| Number of concurrent batch transcription jobs | 250 |
| Number of concurrent batch transcription jobs (Call Analytics) | 100 |
| Job queue bandwidth ratio | 0.9 |
| Number of concurrent HTTP/2 requests | 25 |
| Number of concurrent WebSocket requests | 25 |
| Total number of vocabularies per AWS account | 100 |
| Number of pending vocabularies | 10 |
| Number of concurrently training custom language models | 3 |
| Total number of custom language models per AWS account | 10 |
| Number of categories per AWS account (Call Analytics) | 200 |
| Number of rules per category (Call Analytics) | 20 |
The following operations limits can also be increased upon request:
| Operation | Transactions per second |
|---|---|
| StartTranscriptionJob | 25 |
| StartStreamTranscription | 25 |
| GetTranscriptionJob | 30 |
| DeleteTranscriptionJob | 5 |
| ListTranscriptionJobs | 5 |
| CreateVocabulary | 10 |
| UpdateVocabulary | 10 |
| DeleteVocabulary | 5 |
| GetVocabulary | 20 |
| ListVocabularies | 5 |
| StartCallAnalyticsJob | 10 |
| GetCallAnalyticsJob | 20 |
| ListCallAnalyticsJobs | 5 |
| DeleteCallAnalyticsJob | 5 |
| CreateCallAnalyticsCategory | 10 |
| UpdateCallAnalyticsCategory | 10 |
| DeleteCallAnalyticsCategory | 5 |
| GetCallAnalyticsCategory | 20 |
| ListCallAnalyticsCategories | 5 |
For information about requesting a quota increase, see AWS service quotas in the AWS General Reference.
