Speech-to-Text

Overview

Speech-to-Text (STT) turns spoken audio into written text in Indian languages and English. Using it involves two separate choices:

A model. Gnani Prisma is the model family. Prisma v3.0 and Prisma v2.5 are versions of it. See Models.
An access method. This is how your audio reaches the model: REST, Realtime streaming or Batch.

Any model can be used with any access method.

Choose how to send audio

Access method	Use it when	What happens	Endpoint	Guide
REST	You have a short recording (up to 30 seconds) and want the transcript straight back.	You upload one file and the transcript is in the response.	`POST /stt/v3`	REST transcription
Realtime streaming	The audio is live, such as a phone call or a microphone.	You keep a WebSocket connection open and send audio as it is spoken. Transcripts arrive as each sentence finishes.	`WS /stt/v3/stream`	Realtime streaming
Batch	You have long recordings or many files and can wait for the results.	You create a job, it runs in the background, and you collect the transcripts when it is done.	`POST /stt/v3/batch/jobs`	Batch transcription

Choose a model

Model	Best for	Select it with
Prisma v3.0	Multilingual audio, automatic language detection, speech that mixes languages, and hints such as names and topics	`model=prisma-v3.0`
Prisma v2.5 (default)	Transcribing in the language or languages you specify. Used when you do not choose a model.	Leave out `model`

All models and details are on the Models page.

The 3 in /stt/v3 is the URL version, not the model version. Prisma v2.5 and Prisma v3.0 are both served from /stt/v3. Only the model value decides which model runs.

What works where

In the table, Prisma v3.0 or Prisma v2.5 names the model that offers the feature. A dash means the feature is not available on that access method.

	REST	Realtime streaming	Batch
Select Prisma v2.5	Leave out `model`	Leave out `x-model`, or `x-model: gnani-prisma-v2.5`	`config.model: gnani-prisma-v2.5`
Select Prisma v3.0	`model=prisma-v3.0`	`x-model: prisma-v3.0`	`config.model: prisma-v3.0`
Language detection (`indic-auto`, or 1–4 languages)	Prisma v3.0	Prisma v3.0	Prisma v3.0
`codemix` output style	Prisma v3.0	Prisma v3.0	Prisma v3.0
`transliterate` output style (transcript in Latin letters)	Prisma v3.0	Prisma v3.0	—
Context hints (keyterms, topic, previous text, speaker names)	Prisma v3.0	Prisma v3.0, `keyterms` only	Prisma v3.0, all except `previous_text`
Speaker diarization	—	—	Prisma v2.5, Prisma v3.0

The limits are the same for both models. See Limits.

Gnani APIs

APIs

Use Cases

Reference

Overview

Choose how to send audio

Choose a model

What works where

Next steps

​Overview

​Choose how to send audio

​Choose a model

​What works where

​Next steps

Overview

Choose how to send audio

Choose a model

What works where

Next steps