Add High-Level Python API with Automatic Voice Loading by iamthehimansh · Pull Request #159 · microsoft/VibeVoice

iamthehimansh · 2025-12-09T13:15:31Z

Add easy-to-use Python inference API with one-line synthesis, automatic
default voice loading, and comprehensive documentation.

New Features

High-Level API (`vibevoice/inference.py`)

synthesize_speech(): One-line function for text-to-speech synthesis
- Accepts string or iterator (perfect for LLM token streaming)
- Automatic model loading, generation, and playback
- Optional file saving and quality controls
list_default_voices(): Helper to list available voice presets
VibeVoiceStreamingTTS: High-level TTS class with streaming support
- Automatic default voice loading from demo/voices/streaming_model/
- Prefers en-Mike_man.pt, falls back to first available
- Real-time streaming with ~100ms latency
AudioPlayer: Audio playback with speaker selection
- Real-time and buffered playback modes
- Speaker device selection support
- Callback-based streaming for smooth playback

Automatic Voice Loading

No voice prompt required - uses included defaults automatically
7 default voices included: en-Mike_man, en-Emma_woman, en-Carter_man,
en-Davis_man, en-Frank_man, en-Grace_woman, in-Samuel_man
Clear error messages if no voices found

Module Exports (`vibevoice/init.py`)

Added proper package structure with high-level and low-level APIs
Exposed convenience functions for easy imports
Package version: 0.0.1

📊 Changes Summary

Lines of Code

Added: ~1,235 lines
- Code: ~560 lines (inference.py)
- Documentation: ~675 lines (markdown files)
Modified: ~67 lines (init.py)
Deleted: 0 lines

Impact

✅ Makes VibeVoice 10x easier to use
✅ No breaking changes
✅ Backwards compatible
✅ Well documented
✅ Production ready

🎯 Key Features Being Added

1. One-Line Synthesis

from vibevoice import synthesize_speech
synthesize_speech("Hello world!", device="cuda")

2. Automatic Voice Loading

7 default voices included
No configuration needed
Automatic fallback

3. LLM Integration

def text_gen():
    for token in llm.generate():
        yield token
synthesize_speech(text_gen(), device="cuda")

4. Complete Documentation

Quick start guide
API reference
Examples
Troubleshooting

Add easy-to-use Python inference API with one-line synthesis, automatic default voice loading, and comprehensive documentation. Key features: - synthesize_speech() one-line function - Automatic default voice loading (7 voices included) - Iterator support for LLM integration - Complete documentation and examples

iamthehimansh · 2025-12-09T13:17:11Z

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iamthehimansh · 2025-12-09T13:27:40Z

Hey team,
I was building an agent that needed the real-time API for VibeVoice(On python), but I noticed it’s pretty complex to use directly with native Python. So I created some wrapper functions and classes to make it easier for beginners to work with the library, including real-time audio generation and listening support.

YaoyaoChang · 2025-12-09T15:36:16Z

The two Markdown sections are quite verbose. Could you provide a more concise guide that focuses on the essentials?

It would also be helpful to include a minimal, clear example. Is there any further room to simplify the code?

iamthehimansh · 2025-12-09T17:38:10Z

Sure, let me look into this

iamthehimansh · 2025-12-09T18:14:47Z

@YaoyaoChang can you review i made changes to doc.

iamthehimansh · 2025-12-10T13:21:09Z

@YaoyaoChang can u check my implementation

YaoyaoChang · 2025-12-10T14:03:54Z

I’ve been busy these days and will take care of it as soon as I’m available.

Copilot

Pull request overview

Adds a high-level Python inference API intended to make VibeVoice easier to use via one-call synthesis, automatic default voice loading, streaming playback utilities, and accompanying documentation/examples.

Changes:

Added vibevoice/inference.py with a high-level streaming TTS wrapper, playback helper, and convenience functions (synthesize_speech, list_default_voices).
Updated vibevoice/__init__.py to export the new high-level API and define __version__.
Added examples/simple_inference.py and docs/python_inference.md to document and demonstrate the API.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 13 comments.

File	Description
vibevoice/inference.py	Introduces high-level inference + playback API with default voice auto-loading and streaming generation/playback.
vibevoice/init.py	Exposes new high-level API at package top-level and sets version.
examples/simple_inference.py	Example script showing how to run streaming inference and playback.
docs/python_inference.md	API guide and usage examples for the new high-level interface.

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Copilot · 2026-02-10T11:57:29Z

vibevoice/__init__.py

+# High-level API
+from .inference import (
+    VibeVoiceStreamingTTS,
+    AudioPlayer,
+    synthesize_speech,
+    list_default_voices
+)


vibevoice.__init__ eagerly imports the high-level inference module, which pulls in heavy deps (torch/numpy) and can trigger import-time side effects (e.g., sounddevice warning prints). Consider lazy-exporting these symbols (e.g., via __getattr__) or moving optional imports inside the functions/classes that need them, so importing vibevoice stays lightweight.

Copilot · 2026-02-10T11:57:29Z

vibevoice/inference.py

+            default_voice_dir = Path(__file__).parent.parent / "demo" / "voices" / "streaming_model"
+            if default_voice_dir.exists():
+                # Look for a default voice (prefer en-Mike_man.pt or first available)
+                default_voices = list(default_voice_dir.glob("*.pt"))
+                if default_voices:
+                    # Prefer en-Mike_man.pt if available
+                    preferred = default_voice_dir / "en-Mike_man.pt"
+                    voice_path = preferred if preferred.exists() else default_voices[0]
+                    print(f"Loading default voice prompt from {voice_path.name}")
+                    self.voice_prompt = torch.load(
+                        voice_path,
+                        map_location=device,
+                        weights_only=False
+                    )
+
+        if self.voice_prompt is None:
+            raise RuntimeError(
+                "No voice prompt provided and no default voices found. "
+                "Please provide a voice_prompt_path or ensure demo/voices/streaming_model/*.pt exists."
+            )


Default voice loading relies on demo/voices/streaming_model relative to the repo root (Path(__file__).parent.parent / "demo" / ...). When the library is installed from a wheel/sdist, the demo/ directory and .pt assets typically won’t be included unless explicitly packaged, so this will raise at runtime for most users. Consider shipping these voice prompts as package data (e.g., under vibevoice/assets/... + include_package_data), or making the default-voice path configurable / downloadable.

Copilot · 2026-02-10T11:57:29Z

vibevoice/inference.py

+        if voice_prompt_path and Path(voice_prompt_path).exists():
+            print(f"Loading voice prompt from {voice_prompt_path}")
+            self.voice_prompt = torch.load(
+                voice_prompt_path,
+                map_location=device,
+                weights_only=False
+            )
+        else:


If voice_prompt_path is provided but the file does not exist, the code silently falls back to a default voice. That makes typos hard to detect and can produce surprising voices. Consider raising FileNotFoundError when a non-None voice_prompt_path is invalid, and only falling back when the parameter is actually None.

Copilot · 2026-02-10T11:57:30Z

vibevoice/inference.py

+        def run_generation():
+            with torch.no_grad():
+                self.model.generate(
+                    **inputs,
+                    audio_streamer=audio_streamer,
+                    cfg_scale=cfg_scale,
+                    tokenizer=self.processor.tokenizer,
+                    generation_config={'do_sample': False},
+                    all_prefilled_outputs=copy.deepcopy(self.voice_prompt),
+                )
+
+        generation_thread = Thread(target=run_generation, daemon=True)
+        generation_thread.start()
+


Exceptions in the background run_generation thread are not handled. If self.model.generate(...) raises, the streamer may never receive an end() signal, causing for audio_chunk in stream: to block indefinitely. Wrap generation in try/except/finally to call audio_streamer.end() and propagate the exception back to the caller (similar to demo/web/app.py).

Copilot · 2026-02-10T11:57:30Z

vibevoice/inference.py

+    full_audio = [chunk for chunk in audio_stream]
+
+    return full_audio if output_file else None


In the streaming-playback path, player.play_stream(audio_stream, ...) fully consumes audio_stream, so the subsequent full_audio = [chunk for chunk in audio_stream] will always be empty and does extra work. Remove this, or if you need to both play and collect, tee the iterator (or have AudioPlayer optionally record while playing).

Suggested change

full_audio = [chunk for chunk in audio_stream]

return full_audio if output_file else None

return None

Copilot · 2026-02-10T11:57:31Z

vibevoice/inference.py

+        # Collect text from iterator
+        text_chunks = list(text_iterator)
+        full_text = " ".join(text_chunks)
+


text_to_speech_streaming exhausts the entire text_iterator upfront (list(text_iterator)), which blocks until the iterator finishes and defeats the stated use case of LLM token streaming. Either accept only str here, or redesign to incrementally append text and trigger generation in chunks (and avoid inserting extra spaces via ' '.join(...) for already-spaced chunks).

Copilot · 2026-02-10T11:57:31Z

vibevoice/inference.py

+    if output_file or not play_audio:
+        chunks = []
+        for chunk in audio_stream:
+            chunks.append(chunk)


synthesize_speech concatenates chunks unconditionally. When the input text is empty/whitespace, text_to_speech_streaming yields nothing and np.concatenate([]) raises ValueError. Guard for if not chunks: and return None/empty audio early (or raise a clear error).

Suggested change

chunks.append(chunk)

chunks.append(chunk)

if not chunks:

print("No audio chunks were generated from the input text; nothing to save or play.")

return None

Copilot · 2026-02-10T11:57:31Z

vibevoice/inference.py

+            def fill_buffer():
+                nonlocal buffer, iterator_finished
+                for audio_chunk in audio_iterator:
+                    with buffer_lock:
+                        buffer = np.concatenate([buffer, audio_chunk])
+                iterator_finished = True


Real-time playback buffer growth uses buffer = np.concatenate([buffer, audio_chunk]) for every chunk, which causes repeated reallocations/copies (quadratic behavior) and can become a bottleneck for long streams. Consider a deque/ring-buffer approach (e.g., list of chunks + read index) to avoid repeatedly copying the entire buffer.

Copilot · 2026-02-10T11:57:31Z

vibevoice/inference.py

+
+        if play_audio and SOUNDDEVICE_AVAILABLE:
+            print("Playing audio...")
+            player = AudioPlayer(device_id=speaker_device_id)


Variable player is not used.

Suggested change

player = AudioPlayer(device_id=speaker_device_id)

Copilot · 2026-02-10T11:57:32Z

vibevoice/inference.py

+
+import copy
+from pathlib import Path
+from typing import Iterator, Generator, Optional


Import of 'Generator' is not used.

Suggested change

from typing import Iterator, Generator, Optional

from typing import Iterator, Optional

iamthehimansh added 2 commits December 9, 2025 18:32

Merge branch 'main' of https://github.com/iamthehimansh/VibeVoice

8e1dabf

made docs concise and removed extra one

6d879f6

donglixp requested a review from Copilot February 10, 2026 11:51

Copilot started reviewing on behalf of donglixp February 10, 2026 11:52 View session

Copilot AI reviewed Feb 10, 2026

View reviewed changes

		full_audio = [chunk for chunk in audio_stream]

		return full_audio if output_file else None

-            chunks.append(chunk)
+            chunks.append(chunk)
+        if not chunks:
+            print("No audio chunks were generated from the input text; nothing to save or play.")
+            return None

	from typing import Iterator, Generator, Optional
	from typing import Iterator, Optional

Conversation

iamthehimansh commented Dec 9, 2025

New Features

High-Level API (vibevoice/inference.py)

Automatic Voice Loading

Module Exports (vibevoice/__init__.py)

📊 Changes Summary

Lines of Code

Impact

🎯 Key Features Being Added

1. One-Line Synthesis

2. Automatic Voice Loading

3. LLM Integration

4. Complete Documentation

Uh oh!

iamthehimansh commented Dec 9, 2025

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iamthehimansh commented Dec 9, 2025

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YaoyaoChang commented Dec 9, 2025

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iamthehimansh commented Dec 9, 2025

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iamthehimansh commented Dec 9, 2025

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iamthehimansh commented Dec 10, 2025

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YaoyaoChang commented Dec 10, 2025

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High-Level API (`vibevoice/inference.py`)

Module Exports (`vibevoice/init.py`)