Transform Any Document into AI Podcasts: Your Custom Studio with Dify & ChatTTS - From Solo Lectures to Multi-Voice Interviews - Build It Your Way

From academic papers to dynamic dialogues (podcast)? Easy. Many products are out there. Solo lectures? You bet! Your content, your style.

Not long ago, Google unveiled [NotebookLM](https://notebooklm.google/), an impressive service that transforms documents into human-like podcasts. The quality is so remarkable that it's often indistinguishable from real human speech. But with google, your choice is limited. There's no way to change the tone or voice, and most importantly, the content of the dialogue cannot be modified. While Google keeps their secret sauce under wraps, including how they interact with their Text-to-Speech (TTS) engine, I've discovered some exciting open-source alternatives that give us more control and flexibility.

With Dify and ChatTTS, now we can do whatever we want. If you want to make a podcast of two hosts talking, no problem. If you want to make a one-man-talking lecture, that's also EZPZ!

AI-Generated Podcast / Lecture

The implications of AI-generated podcasts are far-reaching. Imagine classrooms where students can access personalized lectures on any topic, each tailored to their learning pace and style. Public services could provide information in multiple languages instantly, making government resources more accessible to diverse communities. Businesses could create consistent training materials across departments, and content creators could scale their production while maintaining quality. The potential to build a AI-based classroom, and democratize knowledge sharing is enormous.

Finding the Right Tools

While open-source solutions like [pdf-to-podcast](https://github.com/knowsuchagency/pdf-to-podcast) and [open-notebooklm](https://github.com/gabrielchua/open-notebooklm) have been around, they couldn't quite match Google's natural flow and voice quality. Finally, there's Dify, an open-source LLM workflow platform that's giving Google a run for its money. What makes Dify special is its flexibility and friendly user interface - I can modify the prompts to create anything from a solo lecture to a multi-person debate in 5 minutes. The only limitation right now is that it relies on OpenAI's TTS engine, which has limited voice options.

The ChatTTS

Here's where it gets interesting - I've discovered a free workaround that sounds even better than OpenAI's voices. It's called [ChatTTS](https://chattts.com), and it's a game-changer, especially for those like me who need both English and Mandarin capabilities. There's also an all-in-one solution called [ChatTTS_colab](https://github.com/6drf21e/ChatTTS_colab) that lets you generate both monologues and dialogues. The voice quality is remarkably natural, and being open-source means we can expect continuous improvements from the community.

Check out the sample lecture demonstration below!

Step-by-Step Setup Guide

1. Setting Up Your Environment for ChatTTS and Dify

First, install Docker if you haven't: https://www.docker.com/

Next, you'll need to prepare your development environment:

In your computer terminal:

# Install Conda (if you haven't already)

wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh

bash Miniconda3-latest-Linux-x86_64.sh

# Clone Dify repository

git clone https://github.com/langgenius/dify.git

cd dify

cd docker

# Install Dify

docker compose up -d

2. Setting Up Your LLM

I've tested several language models, and here are my findings:

Claude and GPT-4: Produce the most natural and coherent outputs. They excel at maintaining context and generating engaging dialogue. Most importantly, these big models follow system prompt well. That means, we can have a production-ready script in one go.

Llama 3.1: More budget-friendly but slightly less polished results. Still perfectly usable for most purposes. I'd suggest using 405b instead of 8b or 70b.

3. Open the Dify configuration file

4. Confirm your API keys for your chosen model in Dify's settings

5. Configure the model parameters (temperature, max tokens, etc.) and modify the prompt

**Here I delete the "Podcast generate" node, because we only need the script here. You can try the node if you have access to OpenAI's API (p.s. English is not bad). 

6. Customizing Your Prompts

In Dify's workflow, you can customize the output format based on your needs. For a one-person lecture, you can change the relevant prompt and specify that there's only one speaker.

Also, maybe some additional instructions:

- Maintain a conversational tone

- Include clear transitions between topics

- LLMs always use made-up names for the show, give instructions if you have preferences

- Instruct the LLM to add occasional rhetorical questions to engage listeners

For a two-person podcast, and for a ChatTTS ready prompt, try instruct the LLM to follow the format:

Host::Opening introduction and welcome

Guest::Response and expertise sharing

7. Setting Up ChatTTS and generate (It's free and on your own computer!)

1). Visit the [ChatTTS_colab repository](https://github.com/6drf21e/ChatTTS_colab)

2). Follow the installation instructions for your system (we have conda prepared in Step 1)

3). Before generating audio, experiment with different voice seeds

4). Lock in your preferred voice before the final generation

5). Test a few times! You may need to clean the script (e.g., remove some symbols) before generating dialogue.

My Example: Creating a Monkeypox Information Podcast

Let's walk through a real example. I took WHO's monkeypox information page and fed it through my workflow. Simply run the Dify chatbot, upload the webpage and click start!

Here's the generated script snippet:

```

Hello and welcome to Global Health Spotlight! I'm your host, Frank, and today we're diving into a topic that's been making headlines around the world: mpox.

Now, you might be thinking, "Frank, don't you mean monkeypox?" Well, listeners, that's our first lesson of the day. The disease formerly known as monkeypox has been officially renamed to mpox. This change was made to reduce stigma and discrimination associated with the original name. So, let's start using the new term and spread awareness!

Alright, let's get into the nitty-gritty of mpox. What exactly are we dealing with here? Well, mpox is a viral illness caused by the monkeypox virus. It's part of the same family as smallpox, but thankfully, it's generally less severe....

```

I'd suggest removing "", :, ! and adding some emotion tags in to the script, such as:

```

Hello and welcome to Global Health Spotlight! I'm your host Frank, [uv_break] and  today we're diving into a topic that's been making headlines around the world, mpox. 

Now, you might be thinking, Frank, don't you mean monkeypox?  [uv_break] Well, listeners, that's our first lesson of the day.  [uv_break] The disease formerly known as monkeypox has been officially renamed to m pox. [uv_break] This change was made to reduce stigma and discrimination associated with the original name. [uv_break] So, let's start using the new term and spread awareness!

Alright, let's get into the nitty-gritty of mpox. What exactly are we dealing with here? [uv_break] Well, mpox is a viral illness caused by the monkeypox virus. It's part of the same family as smallpox, but thankfully, it's generally less severe. 

```

Let's give it a try! 

After generating the script, I used ChatTTS to bring it to life. Pro tip: When selecting voices, I recommend testing different seeds until you find ones that match your content's tone. For this medical podcast, I chose voices that sounded professional yet approachable.

Here are two examples: 

[ChatTTS] - I only refined the first 3 paragraphs

[OpenAI Alloy]

Which one is better? Please let me know your thoughts.

Tips for Best Results

1. **Script Preparation**

   - Add natural pauses using using ChatTTS tags (if you prefer, check out their instructions)

   - Do NOT include speaker emotions in brackets [excited] or words like "Haha"

   - Clean the script if you hear odd things!

2. **Voice Selection**

   - Test multiple voice seeds before finalizing

   - Consider your target audience when choosing voices

   - Pick the most consistent voices

3. **Quality Control**

   - Review generated scripts for accuracy

   - Check pronunciation of technical terms

Looking Forward

The technology behind AI-generated podcasts is evolving rapidly. As voice synthesis becomes more sophisticated and accessible, we're approaching a future where personalized audio content could become the norm in education, business, and entertainment. Imagine a world where every written piece can be transformed into engaging audio content, making information more accessible to everyone, regardless of their reading preferences or abilities. The combination of advanced language models and natural-sounding voice synthesis is just the beginning. With open-source tools like Dify and ChatTTS leading the way, we're all positioned to be part of this exciting transformation in content creation.

To me, the most shocking thing is picturing the classroom in a few years - there's no traditional teacher's desk at the front, just comfortable learning pods equipped with AI interfaces. Students put on their lightweight AR glasses and begin their personalized learning journeys. The AI system, drawing from vast educational resources, generates custom lectures in their preferred learning style - some students listen to Morgan Freeman-like voices explaining physics, while others engage with animated characters breaking down complex math concepts. The traditional "one-size-fits-all" lecture has evolved into thousands of personalized learning streams happening simultaneously. Student discussions are moderated by AI teaching assistants that guide conversations and encourage critical thinking, while social learning algorithms match students for peer-to-peer sessions based on complementary strengths and weaknesses.

The future is now.