Tutorial: Getting Started with OpenAI GPT-4o ("Omni")

OpenAI GPT-4o, also known as "Omni," is the latest evolution of the GPT series, offering native multimodal capabilities, improved performance, and enhanced functionality. This tutorial will guide you through the key features, migration considerations, and usage best practices for GPT-4o.

What's New in GPT-4o?

Key Features:

1. Multimodal Support: GPT-4o natively supports text, image, and audio inputs and can generate text, images, or spoken outputs directly from a single endpoint.
2. Improved Performance:
   • Latency: 2-3× faster than GPT-4.
   • Cost: Approximately 35% cheaper per token (applies to both prompt and completion tokens).
3. Context Window: Holds up to 128,000 tokens.
4. Streaming Output: Enabled by default for real-time interactions.
5. Advanced Capabilities:
   • Chain-of-thought reasoning.
   • Built-in function and tool calling.
   • ReAct-style planning.
   • Vision embeddings for image understanding.
   • Automatic voice diarisation for multi-speaker audio.
   • Real-time voice "back-channel" cues (e.g., handling interruptions or acknowledgments).

Upgrading from GPT-4 to GPT-4o

API Usage:

1. Endpoint: Use the same endpoint as GPT-4:

   POST /v1/chat/completions 2. Model Specification: Set the model parameter to "gpt-4o-2024-05-13":

   json { "model": "gpt-4o-2024-05-13", "messages": [] } 3. Multimodal Inputs: * Images: Include image URLs in the content field of a message:

   ```json
   {
     "role": "user",
     "content": "What is this image about? [image_url]https://example.com/image.jpg[/image_url]"
   }
   ```
   

   • Audio: Send 48 kHz, 16-bit PCM audio chunks with the audio/* content type.
   • No New SDK Required: Use the same JSON structure as GPT-4. No additional libraries or SDKs are needed.

Migration Considerations

1. Drop GPT-4 Workarounds:
   • Remove any temperature-related workarounds, as GPT-4o behaves differently.
2. Tighten Guardrails:
   • GPT-4o is more literal in its responses. Adjust your prompts and guardrails accordingly.
3. Function Call JSON Shapes:
   • GPT-4o returns different JSON shapes for function calls. Validate and parse responses carefully.
4. Rate Limits:
   • Rate limits remain the same as GPT-4 tiers. Plan your usage accordingly.

Working with GPT-4o's Capabilities

Chain-of-Thought and ReAct

GPT-4o natively supports chain-of-thought reasoning and ReAct-style planning. Use these capabilities for complex tasks:

{
  "role": "user",
  "content": "Explain how to solve this problem step-by-step:"
}

Vision Embeddings

Leverage GPT-4o's built-in vision embeddings to analyze and compare images:

{
  "role": "user",
  "content": "Compare the styles of these two images: [image_url]https://example.com/image1.jpg[/image_url] and [image_url]https://example.com/image2.jpg[/image_url]"
}

Audio Processing

Send audio inputs for transcription, analysis, or generation:

{
  "role": "user",
  "content": "Transcribe this audio: [audio_url]https://example.com/audio.wav[/audio_url]"
}

Best Practices and Gotchas

Best Practices:

• Multimodal Inputs: Experiment with combining text, images, and audio inputs for richer interactions.
• Streaming: Utilize real-time streaming for conversational applications.
• Cost Efficiency: Take advantage of the reduced cost per token for larger-scale applications.

Common Gotchas:

1. U.S.-English Bias in Voice: GPT-4o still has a bias toward U.S.-English voices.
2. Image Size Limit: Maximum image size is capped at 4 MB.
3. Audio Context Reset: Audio context resets after 90 seconds of silence. Plan for this in real-time applications.

Conclusion

GPT-4o represents a significant leap forward in multimodal AI capabilities, offering faster performance, lower costs, and native support for text, images, and audio. By following this guide, you can seamlessly migrate from GPT-4 and unlock the full potential of GPT-4o for your applications. Start building today and explore the possibilities of multimodal AI!