Question 1

What is OpenAI: TTS-1 HD?

Accepted Answer

OpenAI: TTS-1-HD is a text-to-speech model optimised for high audio fidelity, converting text into natural-sounding spoken audio with greater clarity and detail than the standard tts-1 model, at roughly double the cost.
It ships six built-in voices (alloy, echo, fable, onyx, nova, shimmer), supports six output containers (mp3, opus, aac, flac, wav, pcm) and adjustable speech speed from 0.25x to 4.0x. Input is capped at 4096 characters per request. For lower-latency real-time use cases, use tts-1; for voice-style control via natural-language instructions, use gpt-4o-mini-tts.

Question 2

How much does OpenAI: TTS-1 HD cost?

Accepted Answer

OpenAI: TTS-1 HD costs $30.00/1M tokens for input tokens.

Question 3

What is the context length of OpenAI: TTS-1 HD?

Accepted Answer

OpenAI: TTS-1 HD has a 4,096 token context window.

Question 4

Does OpenAI: TTS-1 HD support tool calling and structured outputs?

Accepted Answer

Yes. OpenAI: TTS-1 HD supports structured outputs.

Question 5

What inputs and outputs does OpenAI: TTS-1 HD support?

Accepted Answer

OpenAI: TTS-1 HD accepts text as input and returns audio.

Question 6

What other models does OpenAI have?

Accepted Answer

OpenAI: GPT-5.6 Luna, OpenAI: GPT-5.3-Codex, OpenAI: GPT Image 2 and 56 more are other models from OpenAI.

Question 7

When was OpenAI: TTS-1 HD released?

Accepted Answer

OpenAI: TTS-1 HD was released on Nov 6, 2023.