NoPause Python SDK

Stream your LLM output in real-time through NoPause TTS API to produce seamless speech, putting an end to LLM latency woes.

Installation

You can install the NoPause TTS library via pip:

pip install nopause

Quick Start

To use NoPause SDK, you will need an API key. You could get one by signing up at NoPause.

Stream Synthesizing Audio and Playback

Here's an example to synthesize audio using NoPause and stream play the audio:

(1) Install SoundDevice to play audio locally.

pip install sounddevice

(2) Fill in the API key of NoPause, then run this example:

import time
import sounddevice as sd
import nopause

nopause.api_key = "your_nopause_api_key_here"

def text_stream():
    sentence = "Hello! I am a helpful assistant from NoPause IO. I'm here to assist you with any questions or tasks you might have. How can I help you today?"
    for char in sentence:
        time.sleep(0.01) # simulate streaming text. It could be also removed.
        yield char
        print(char, end='', flush=True)
    print()

text_generator = text_stream()
audio_chunks = nopause.Synthesis.stream(text_generator, voice_id="Zoe")

stream = sd.RawOutputStream(
        samplerate=24000, blocksize=4800,
        device=sd.query_devices(kind="output")['index'],
        channels=1, dtype='int16',
        )

with stream:
    for chunk in audio_chunks:
        stream.write(chunk.data)
    time.sleep(1)

print('Play done.')

Alternatively, you could play audio with PyAudio. For more details, see pyaudio example.

Streaming Audio Playback Generated from ChatGPT Output

Here's an example of using NoPause TTS along with OpenAI's ChatGPT API:

(1) Install OpenAI SDK to access ChatGPT:

pip install openai

Note, the API key of ChatGPT should be applied from OpenAI first.

(2) Fill in the API keys for both OpenAI and NoPause, then run this example:

import time
import sounddevice as sd
import openai
import nopause

openai.api_key = "your_openai_api_key_here"
nopause.api_key = "your_nopause_api_key_here"

def chatgpt_stream(prompt: str):
    responses = openai.ChatCompletion.create(
        model="gpt-3.5-turbo",
        messages=[
                {"role": "system", "content": "You are a helpful assistant from NoPause IO."},
                {"role": "user", "content": prompt},
        ],
        stream=True,
    )
    print("[User]: {}".format(prompt))
    print("[Assistant]: ", end='')

    def generator():
        for response in responses:
            content = response["choices"][0]["delta"].get("content", '')
            print(content, end='')
            yield content
        print()
    return generator

text_generator = chatgpt_stream('Hello, who are you?')
audio_chunks = nopause.Synthesis.stream(text_generator, voice_id="Zoe")

stream = sd.RawOutputStream(
        samplerate=24000, blocksize=4800,
        device=sd.query_devices(kind="output")['index'],
        channels=1, dtype='int16',
        )

with stream:
    for chunk in audio_chunks:
        stream.write(chunk.data)
    time.sleep(1)

print('Play done.')

Try Synthesis with Chat Mode

You can also use the chat example to communicate with GPT or repeat a sentence to try the synthesis.

# install extra package
pip install python-dotenv readline

# prepare API key in the workdir based on .env file
echo "OPENAI_API_KEY=<your-openai-key>" >> .env
echo "NOPAUSE_API_KEY=<your-nopause-key>" >> .env

# run the example
python examples/chat.py

Note that there are several commands you can input in the chat mode: [done]: ends the current conversation and prepares for a new one. It clears the memory of GPT.

[exit]: exit the chat mode and export a timestamp record to a file.

[repeat] content or [r] content: the assistant will repeat your content. It is used to test what you want to synthesize. The content is not added to the GPT memory.

For more examples, such as Asynchronous Streaming Audio Synthesis and Playing or Interrupting Synthesis, see examples/*.py and tests/*.py.

Manage Voices

You can add, delete and list custom voices with the Voice class. Here's an example to add a custom voice:

nopause.api_key = "your_nopause_api_key_here"

# show all available voices
print(nopause.Voice.get_voices())

# add a custom voice
audio_files = [
    "path/to/audio1.wav",
    "path/to/audio2.wav",
    "path/to/audio3.wav",
    "path/to/audio4.wav",
    "path/to/audio5.wav",
]
response = nopause.Voice.add(audio_files, voice_name="my_voice", language="en", description="my voice")
voice_id = response.voice_id
print(f'voice id is: {voice_id}')

# delete a custom voice
nopause.Voice.delete(voice_id)

Integration

We have integrated the Python SDK into Vocode, see details at https://github.com/NoPause-io/vocode-python. The example allows you to interact with LLM using the microphone and speaker on your local PC, you can experience it by executing the command below.

# Clone the the source code of vocode-python and select the `support_nopause_dual_stream` branch
git clone https://github.com/NoPause-io/vocode-python.git -b support_nopause_dual_stream
cd vocode-python

# If you have not installed poetry, install it first.
pip install poetry

# Install vocode from local
poetry install

# Install NoPause SDK
pip install nopause

# Create and configure the environments variables of ASR, LLM and TTS (NoPause) in the `.env` file in the workdir
# Such as:
#   AZURE_SPEECH_KEY = 
#   AZURE_SPEECH_REGION = "eastus"
#   OPENAI_API_KEY =
#   NO_PAUSE_API_KEY =

# Run this example
python quickstarts/dual_streaming_conversation_with_nopause_tts.py

Besides, you can also use Vocode + NoPause + Twillio to make phone calls. After you prepare all the servers according to vocode document, it is simple to use our synthesizer in a phone call. Here is an example of outbound call.

1. Similarly, prepare the environments variables of ASR, LLM and TTS (NoPause) in the .env file (assume that you have added BASE_URL, TWILIO_ACCOUNT_SID and TWILIO_AUTH_TOKEN variables)
2. Add synthesizer_config for OutboundCall object in the apps/telephony_app/outbound_call.py file

outbound_call = OutboundCall(
        base_url=BASE_URL,
        to_phone="+15555555555",
        from_phone="+15555555555",
        config_manager=config_manager,
        transcriber_config=AzureTranscriberConfig.from_telephone_input_device(endpointing_config=PunctuationEndpointingConfig()),
        agent_config=ChatGPTAgentConfig(
                initial_message=BaseMessage(text="Hello, how can I help you today?"),
                prompt_preamble="""The AI is having a pleasant conversation about life""",
                dual_stream=True # Enable this to send text token by token
            ), # Instead of using original SpellerAgent, you can also chat with GPT
        synthesizer_config=NoPauseSynthesizerConfig.from_telephone_output_device() # Add NoPause synthesizer
    )

3. Fill the to_phone and from_phone and then run the outbound_call.py script

python apps/telephony_app/outbound_call.py

API Reference

Class Synthesis

A WebSocket client for NoPause TTS synthesis API.

Synthesis.stream()

Creates a dual-stream synthesis.

Arguments

• text_iter: An iterable of strings to be synthesized.
• api_key: NoPause API key.
• voice_id: Which voice to use.
• model_name: Which NoPause model to use (default: 'nopause-en-beta').
• language: Which language to use (default: 'en').
• dual_stream_config: A DualStreamConfig object (default: None).
• audio_config: An AudioConfig object (default: None).
• api_key: The API key of NoPause. (default: None).
• api_base: The base URL for the NoPause API (default: None).
• api_version: The version of the NoPause API to use (default: None).

Returns

• A generator of AudioChunk objects.

Synthesis.astream()

Creates a dual-stream synthesis (asynchronous version). The arguments are the same as Synthesis.stream(), except that the text_iter should be an asynchronous generator. And it returns an asynchronous generator of AudioChunk objects.

Stream with Pre-Connected Synthesizer

In addition to utilizing Synthesis.stream(text_iterator, **config) for one-step synthesis, you can connect beforehand to further decrease latency.

synthesizer = Synthesis(**config).connect()
#- prepare other resources -#
synthesizer.stream(text_iterator)

For more details, see the note of synthesis.py

Class Voice

The Voice class enables you to add or remove custom voices, as well as list all existing voices.

Voice.add()

This API can be utilized to replicate a new voice using multiple references.

Arguments

• audio_files: A list of local file path of audios to create a custom voice. All auidos should be sampled from the same person. (max number of files: 10)
• voice_name: Custom voice name. if not provided, it will be randomly generated. (default: None)
• language: The language of target voice. (default: en)
• description: The description of target voice. (default: None)
• gender: The gender of target voice. (default: None)
• api_key: The API key of NoPause. (default: None).
• api_base: The base URL for the NoPause API (default: None).
• api_version: The version of the NoPause API to use (default: None).

Returns

AddVoiceResponse

• voice_id: The server generated voice ID for the target voice.
• voice_name: The name of target voice.
• trace_id: An ID used to track the current request. It can help locate reported issues.

Voice.get_voices()

This API is used to list available voices page by page.

Arguments

• page: The index of page to view. (1-based, default: 1)
• page_size: The size of one page. (default: 100)
• api_key: The API key of NoPause. (default: None).
• api_base: The base URL for the NoPause API (default: None).
• api_version: The version of the NoPause API to use (default: None).

Returns

VoicesResponse

• voices: A list of a series voice which contains the voice_name: str, voice_id: str, voice_type: str, description: str and audios: list[audio_filename]
• total: Total number of available voices, including prebuilt voices and custome built voices.
• trace_id: An ID used to track the current request. It can help locate reported issues.

Voice.delete()

This API could be used to delete a custom voice by voice ID.

Arguments

• voice_id: The voice ID of target voice to delete.
• api_key: The API key of NoPause. (default: None).
• api_base: The base URL for the NoPause API (default: None).
• api_version: The version of the NoPause API to use (default: None).

Returns

DeleteVoiceResponse

• voice_id: The unique voice ID of target voice.
• voice_name: The name of target voice.
• trace_id: An ID used to track the current request. It can help locate reported issues.