Pixelle-Video Text-to-Speech (TTS) Engines: Complete Guide to Edge-TTS, Index-TTS 2, and Custom ComfyUI Nodes

Pixelle-Video supports three categories of TTS engines: Microsoft Edge-TTS (local inference), Index-TTS 2 (voice cloning via ComfyUI), and any custom ComfyUI-compatible TTS node through workflow-based execution.

The open-source Pixelle-Video project (AIDC-AI/Pixelle-Video) provides a flexible text-to-speech architecture that routes between local inference and ComfyUI workflow execution. This guide covers all supported TTS engines, their configuration, and implementation details based on the actual source code.

Edge-TTS: Local Microsoft Speech Synthesis

How Edge-TTS Works in Pixelle-Video

The Edge-TTS engine provides free, local text-to-speech using Microsoft's Edge browser speech service. This is the default TTS method when inference_mode="local" is specified.

The implementation resides in pixelle_video/utils/tts_util.py, with voice definitions located in pixelle_video/tts_voices.py.

Configuring Edge-TTS Voices

Voice selection uses the EDGE_TTS_VOICES catalog. Here's how to use Edge-TTS programmatically:

# Generate speech locally with Edge-TTS

audio_path = await pixelle_video.tts(
    text="Hello, world!",
    inference_mode="local",          # forces Edge-TTS

    voice="en-US-JennyNeural",      # any ID from EDGE_TTS_VOICES

    speed=1.2                        # 20% faster

)
print(f"Audio saved to {audio_path}")

The speed parameter converts to Edge-TTS's rate parameter via the speed_to_rate function in tts_util.py.

Edge-TTS Source Files

File	Purpose
pixelle_video/services/tts_service.py	Routes to _call_local_tts (lines 41-68)
pixelle_video/utils/tts_util.py	Async edge_tts function with networking and retries
pixelle_video/tts_voices.py	EDGE_TTS_VOICES catalog

Index-TTS 2: Voice Cloning via ComfyUI

How Index-TTS 2 Works in Pixelle-Video

Index-TTS 2 provides voice cloning capabilities through a self-hosted ComfyUI workflow. This engine requires inference_mode="comfyui" with the specific workflow path workflows/selfhost/tts_index2.json.

The workflow contains the IndexTTS2BaseNode node, which handles the voice cloning inference.

Using Index-TTS 2 for Voice Cloning

# Use the built-in Index-TTS 2 workflow (voice cloning)

audio_path = await pixelle_video.tts(
    text="床前明月光，疑是地上霜。",
    inference_mode="comfyui",               # run a ComfyUI workflow

    workflow="selfhost/tts_index2.json",    # explicit workflow path

    voice="zh-CN-YunjianNeural",           # passed to the node (optional)

    speed=1.0
)
print(f"Cloned voice audio: {audio_path}")

Index-TTS 2 Source Files

File	Purpose
workflows/selfhost/tts_index2.json	Self-hosted workflow with IndexTTS2BaseNode
pixelle_video/services/tts_service.py	_call_comfyui_workflow method
config.example.yaml	Default workflow configuration under comfyui.tts.default_workflow

Custom ComfyUI TTS Nodes

Extending Pixelle-Video with Custom TTS Workflows

Pixelle-Video supports any ComfyUI-compatible TTS node through custom workflow files. This provides unlimited extensibility for specialized TTS engines or third-party plugins.

Requirements for custom TTS workflows:

• File must be placed under workflows/ directory (e.g., workflows/selfhost/)
• Must contain a TTS node with the tts_ prefix
• Must be invoked with inference_mode="comfyui"

Creating and Using Custom TTS Workflows

Create a workflow file workflows/selfhost/my_custom_tts.json with your TTS node:

audio_path = await pixelle_video.tts(
    text="Custom TTS node example",
    inference_mode="comfyui",
    workflow="selfhost/my_custom_tts.json"
)

The workflows/selfhost/tts_edge.json provides a reference implementation for wrapping Edge-TTS as a ComfyUI workflow.

TTS Service Architecture

Entry Point and Routing Logic

The pixelle_video/services/tts_service.py file implements the core TTS service with the __call__ method as the entry point.

Routing logic:

1. Determines inference_mode from call arguments or config (self.config.get("inference_mode"))
2. Routes to _call_local_tts for Edge-TTS
3. Routes to _call_comfyui_workflow for any ComfyUI-based engine

Workflow Resolution

The _resolve_workflow method loads workflow JSON files from:

• workflows/selfhost/ for self-hosted deployments
• workflows/runninghub/ for cloud (RunningHub) deployments

Default workflow paths are configured in config.example.yaml under the comfyui.tts.default_workflow key.

Summary

• Edge-TTS provides free, local Microsoft speech synthesis via inference_mode="local" — implemented in pixelle_video/utils/tts_util.py with voices defined in pixelle_video/tts_voices.py
• Index-TTS 2 enables voice cloning through the self-hosted ComfyUI workflow workflows/selfhost/tts_index2.json containing the IndexTTS2BaseNode
• Custom ComfyUI nodes extend TTS capabilities infinitely — any node with tts_ prefix in a workflow file under workflows/ can be invoked via inference_mode="comfyui"
• Central routing occurs in pixelle_video/services/tts_service.py with _call_local_tts and _call_comfyui_workflow methods handling engine-specific execution

Frequently Asked Questions

How do I switch between TTS engines in Pixelle-Video?

Set the inference_mode parameter when calling the TTS service. Use "local" for Edge-TTS or "comfyui" for Index-TTS 2 and custom workflows. The pixelle_video/services/tts_service.py file routes requests based on this parameter, falling back to configuration values if not specified.

Can I use my own voice with Pixelle-Video's TTS?

Yes, through Index-TTS 2 in workflows/selfhost/tts_index2.json. This workflow uses the IndexTTS2BaseNode for voice cloning. You can also create custom workflows with other voice cloning nodes by placing them under workflows/ with the tts_ prefix and invoking with inference_mode="comfyui".

Where are TTS voices configured in Pixelle-Video?

Edge-TTS voices are defined in pixelle_video/tts_voices.py in the EDGE_TTS_VOICES list. For ComfyUI-based engines, voice selection happens within the workflow JSON files under workflows/selfhost/ or workflows/runninghub/. The default workflow path is set in config.example.yaml under comfyui.tts.default_workflow.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}