Change Log

April 1, 2025

April 2025

Text to Speech (TTS)

Model APIs

Bulbul v2 Released

Introduced bulbul:v2, the latest version of our Indian Text-to-Speech model.

  • More natural and expressive voice output with better emotional tone
  • Enhanced preprocessing for improved handling of mixed-language inputs

Bulbul v1 Deprecation Notice

bulbul:v1 will be officially deprecated on April 30, 2025. Users should migrate to bulbul:v2 to ensure uninterrupted service.

24kHz Audio Support

Speech generation now supports 24kHz sample rate for higher quality output.

Speech to Text (STT)

Model APIs

Batch ASR API Released

New Batch ASR API allows uploading up to 20 audio files (up to 60 minutes each).

  • Ideal for calls, meetings, and long-form media
  • Available in both speech-to-text and speech-to-text-translate endpoints

Real-Time API Improvements

Improved transcription speed for real-time requests.

  • 3× faster processing for up to 30s audio snippets
  • Optimized for use cases like voice bots and instant assistants

Streaming WebSocket (Beta)

WebSocket-based real-time transcription now in beta. Early access available via the Sarvam Discord community.

Text

Model APIs

Language Detection Enhancements

Added source_language_code to API responses.

  • Automatically detects input language
  • Improves performance on multilingual and code-switched text

Indic Translation Upgrades

Improved support for two-way translation between Indic and English.

  • Supports colloquial, modern, classical, and formal registers
  • Ideal for education, localization, and content creation platforms

New APIs Introduced

  • Transliterate API
    Converts text between writing systems while preserving pronunciation

  • Language Identification (LID) API
    Detects both language and script from input

Documentation

Model APIs

Cookbook Updated

  • Added new real-world examples for Batch ASR and Bulbul v2 usage
  • Included advanced translation flows (e.g., tone-aware translation)
  • Refreshed LID and transliteration notebooks
  • Integrated with latest SDK structure

Cleanup and Refactoring

Removed deprecated analytics and parse APIs from SDK for better maintainability.