Supported Files and Limits

Transcription:BatchReal-TimeDeployments:All

Supported File Types

The following input types are supported for transcription:

Raw Audio streaming (RT only):

• PCM F32 LE raw audio stream (32-bit float)
• PCM S16 LE raw audio stream (16- bit signed int)
• mu-law

Files (RT and Batch):

• 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, but hinted at in the name, for example files commonly given extensions like ".raw" or ".g729", cannot be processed in batch mode.

Rate Limiting and Fair Usage

Speechmatics Batch SaaS applies rate limiting and fair queueing to provide a consistently high quality of service to all users.

If you make a large number of requests in a short period of time, some of these requests may fail with the response HTTP 429 - Rate Limited. To minimize the possibility of encountering rate limiting errors, we recommend that you do not exceed the following rates:

• 10 new jobs per second (POST API calls)
• 50 job status requests per second (GET API calls). Note that Speechmatics recommends using Notifications for job status updates in production

Aside from rate limiting, there is no limit to the number of jobs that you can submit. However, Speechmatics Batch SaaS applies a fair queueing policy which means that if you have a large number of jobs in progress at one time, the most recently submitted jobs may take longer to complete.

Real-Time Session Limits

Speechmatics Real-Time SaaS applies the following limits to the number of concurrent sessions:

Customer Type	Maximum Concurrent Sessions
On-demand - Free Trial	2
On-demand - Active Payment Card	10
Enterprise	Custom

Please reach out to Support if you need to increase the above limits.

We recommend that each Speechmatics Real-Time SaaS session does not exceed 24 hours in duration and sessions longer than this may be terminated. Since unpredictable network issues can cause WebSocket connections to be dropped, we also recommend graceful handling of session termination for long-running sessions.

File Size Limits

If you submit your media file in the body of the /jobs POST request to Speechmatics Batch SaaS, the file must be less than 1 GB in size or the job will be rejected. To process files larger than 1 GB, you can provide the URL of the audio file in the job config as described in the Fetch URL documentation.

Data Retention Limits

Audio files, transcripts, and configuration data are stored in the Speechmatics Batch SaaS for 7 days. Any request to retrieve a transcript or file more than 7 days after it was processed will receive an HTTP 404 error message and a status of expired. You can delete audio or transcripts in advance of this 7 day period - see the API Reference for details.

Speechmatics Real-Time SaaS does not store audio files, transcripts, or configuration data.