OpenAI, on Thursday, introduced new audio models in application programming interface (API) that offer improved performance in accuracy and reliability. The San Francisco-based AI firm released three new artificial intelligence (AI) models for both speech-to-text transcription and text-to-speech (TTS) functions. The company claimed that these models will enable developers to build applications with agentic workflows. It also stated that the API can enable businesses to automate customer support-like operations. Notably, the new models are based on the company’s GPT-4o and GPT-4o mini AI models.

OpenAI Brings New Audio Models in API

In a blog post, the AI firm detailed the new API-specific AI models. The company highlighted that over the years it has released several AI agents such as Operator, Deep Research, Computer-Using Agents, and the Responses API with built-in tools. However, it added that the true potential of agents can only be unlocked when they can perform intuitively and interact across mediums beyond text.

There are three new audio models. GPT-4o-transcribe and GPT-4o-mini-transcribe are the speech-to-text models and the GPT-4o-mini-tts is, as the name suggests, a TTS model. OpenAI claims that these models outperform its existing Whisper models which were released in 2022. However, unlike the older models, the new ones are not open-source.

Coming to the GPT-4o-transcribe, the AI firm stated that it showcases improved “word error rate” (WER) performance on the Few-shot Learning Evaluation of Universal Representations of Speech (FLEURS) benchmark which tests AI models on multilingual speech across 100 languages. OpenAI said the improvements were a result of targeted training techniques such as reinforcement learning (RL) and extensive midtraining with high-quality audio datasets.

These speech-to-text models can capture audio even in challenging scenarios such as heavy accents, noisy environments, and varying speech speeds.

The GPT-4o-mini-tts model also comes with significant improvements. The AI firm claims that the models can speak with customisable inflections, intonations, and emotional expressiveness. This will enable developers to build applications that can be used for a wide range of tasks including customer service and creative storytelling. Notably, the model only offers artificial and preset voices.

OpenAI’s API pricing page highlights that the GPT-4o-based audio model will cost $40 (roughly Rs. 3,440) per million input tokens and $80 (roughly Rs. 6,880) per million output tokens. On the other hand, the GPT-4o mini-based audio models will be charged at the rate of $10 (roughly Rs. 860) per million input tokens and $20 (roughly Rs. 1,720) per million output tokens.

All of the audio models are now available to developers via API. OpenAI is also releasing an integration with its Agents software development kit (SDK) to help users build voice agents.