About NVIDIA ASR NIM Microservice

The NVIDIA Automatic Speech Recognition (ASR) NIM microservice converts spoken audio into text. It packages pre-trained NeMo models with the full NVIDIA inference stack (TensorRT, Triton) into self-contained containers that handle model download, optimization, and serving.

ASR NIMs support two inference modes:

• Streaming: Returns partial transcripts as audio arrives. Use for real-time applications such as live captioning and voice assistants.

• Offline: Processes the full audio and returns a complete transcript. Use for batch processing of recorded files.

Available Models

ASR NIMs ship multiple model families optimized for different use cases. Choose based on your language, latency, and capability requirements.

Model	Languages	Modes	Key Capability
Parakeet CTC	English, Vietnamese, Spanish, Mandarin, Taiwanese	Streaming + Offline	Low-latency transcription across multiple languages
Parakeet TDT v2	English	Offline	Word-level timestamps
Parakeet RNNT Multilingual	25+ languages	Streaming + Offline	Auto language detection across 25+ languages
Conformer CTC	Spanish	Streaming + Offline	Spanish transcription
Whisper Large v3	100+ languages	Offline	Transcription and translation to English
Canary 1b	26 languages	Offline	Transcription and bidirectional translation

For GPU memory requirements and all available model profiles, refer to the ASR support matrix.

Choosing a Model

• Single language, low latency: Parakeet CTC models provide the fastest streaming transcription for their supported languages.

• Word-level timestamps: Parakeet TDT v2 returns start and end times for each word.

• Many languages, one model: Parakeet RNNT Multilingual covers 25+ languages with automatic language detection in both streaming and offline modes.

• Maximum language coverage: Whisper Large v3 supports 100+ languages (offline only).

• Translation: Whisper translates any supported language to English. Canary 1b supports bidirectional translation across 26 languages.

Next Steps

• Deploy and Run ASR Models: Step-by-step deployment and inference commands for each model.

• Customize ASR Models: Word boosting, custom vocabularies, and deploying fine-tuned NeMo checkpoints.

• ASR Tutorial: Deploy your first ASR NIM from scratch.