app.py

import gradio as gr
import tempfile
import openai
import requests
import os
from functools import partial

def tts(
    input_text: str,
    model: str,
    voice: str,
    api_key: str,
    response_format: str = "mp3",
    speed: float = 1.0,
) -> str:
    """
    Convert input text to speech using OpenAI's Text-to-Speech API.

    Parameters:
        input_text (str): The text to be converted to speech.
        model (str): The model to use for synthesis (e.g., 'tts-1', 'tts-1-hd').
        voice (str): The voice to use when generating the audio.
        api_key (str): OpenAI API key.
        response_format (str): Format of the output audio. Defaults to 'mp3'.
        speed (float): Speed of the generated audio. Defaults to 1.0.

    Returns:
        str: File path to the generated audio file.

    Raises:
        gr.Error: If input parameters are invalid or API call fails.
    """
    if not api_key.strip():
        raise gr.Error(
            "API key is required. Get an API key at: https://platform.openai.com/account/api-keys"
        )

    if not input_text.strip():
        raise gr.Error("Input text cannot be empty.")

    if len(input_text) > 4096:
        raise gr.Error("Input text exceeds the maximum length of 4096 characters.")

    if speed < 0.25 or speed > 4.0:
        raise gr.Error("Speed must be between 0.25 and 4.0.")

    headers = {
        "Authorization": f"Bearer {api_key}",
        "Content-Type": "application/json",
    }

    data = {
        "model": model,
        "input": input_text,
        "voice": voice,
        "response_format": response_format,
        "speed": speed,
    }

    try:
        response = requests.post(
            "https://api.openai.com/v1/audio/speech",
            headers=headers,
            json=data,
        )
        response.raise_for_status()
    except requests.exceptions.HTTPError as http_err:
        raise gr.Error(f"HTTP error occurred: {http_err} - {response.text}")
    except Exception as err:
        raise gr.Error(f"An error occurred: {err}")

    # The content will be the audio file content
    audio_content = response.content

    file_extension = response_format.lower()
    # PCM is raw data, so it does not have a standard file extension
    if file_extension == "pcm":
        file_extension = "raw"

    with tempfile.NamedTemporaryFile(
        suffix=f".{file_extension}", delete=False
    ) as temp_file:
        temp_file.write(audio_content)
        temp_file_path = temp_file.name

    return temp_file_path


def main():
    """
    Main function to create and launch the Gradio interface.
    """
    MODEL_OPTIONS = ["tts-1", "tts-1-hd"]
    VOICE_OPTIONS = ["alloy", "echo", "fable", "onyx", "nova", "shimmer"]
    RESPONSE_FORMAT_OPTIONS = ["mp3", "opus", "aac", "flac", "wav", "pcm"]

    # Predefine voice previews URLs
    VOICE_PREVIEW_URLS = {
        voice: f"https://cdn.openai.com/API/docs/audio/{voice}.wav"
        for voice in VOICE_OPTIONS
    }

    # Download audio previews to disk before initiating the interface
    PREVIEW_DIR = "voice_previews"
    os.makedirs(PREVIEW_DIR, exist_ok=True)

    VOICE_PREVIEW_FILES = {}
    for voice, url in VOICE_PREVIEW_URLS.items():
        local_file_path = os.path.join(PREVIEW_DIR, f"{voice}.wav")
        if not os.path.exists(local_file_path):
            try:
                response = requests.get(url)
                response.raise_for_status()
                with open(local_file_path, "wb") as f:
                    f.write(response.content)
            except requests.exceptions.RequestException as e:
                print(f"Failed to download {voice} preview: {e}")
        VOICE_PREVIEW_FILES[voice] = local_file_path

    # Set static paths for Gradio to serve
    gr.static(PREVIEW_DIR)

    with gr.Blocks(title="OpenAI - Text to Speech") as demo:
        gr.Markdown("# OpenAI Text-to-Speech Demo")
        with gr.Row():
            with gr.Column(scale=1):
                with gr.Group():
                    preview_audio = gr.Audio(
                        interactive=False,
                        label="Preview Audio",
                        value=None,
                        visible=True,
                    )

                    # Function to play the selected voice sample
                    def play_voice_sample(voice):
                        return gr.update(value=VOICE_PREVIEW_FILES[voice])

                    # Create buttons for each voice
                    for voice in VOICE_OPTIONS:
                        voice_button = gr.Button(
                            value=f"{voice.capitalize()}",
                            variant="secondary",
                            size="sm",
                        )
                        voice_button.click(
                            fn=partial(play_voice_sample, voice=voice),
                            outputs=preview_audio,
                        )

                with gr.Column(scale=1):
                    api_key_input = gr.Textbox(
                        label="OpenAI API Key",
                        info="https://platform.openai.com/account/api-keys",
                        type="password",
                        placeholder="Enter your OpenAI API Key",
                    )
                    model_dropdown = gr.Dropdown(
                        choices=MODEL_OPTIONS,
                        label="Model",
                        value="tts-1",
                        info="Select tts-1 for speed or tts-1-hd for quality.",
                    )
                    voice_dropdown = gr.Dropdown(
                        choices=VOICE_OPTIONS,
                        label="Voice Options",
                        value="echo",
                        info="The voice to use when generating the audio.",
                    )
                    response_format_dropdown = gr.Dropdown(
                        choices=RESPONSE_FORMAT_OPTIONS,
                        label="Response Format",
                        value="mp3",
                    )
                    speed_slider = gr.Slider(
                        minimum=0.25,
                        maximum=4.0,
                        step=0.05,
                        label="Voice Speed",
                        value=1.0,
                    )

            with gr.Column(scale=2):
                input_textbox = gr.Textbox(
                    label="Input Text",
                    lines=10,
                    placeholder="Type your text here...",
                )
                # Add a character counter below the input textbox
                char_count_text = gr.Markdown("0 / 4096")

                # Function to update the character count
                def update_char_count(input_text):
                    char_count = len(input_text)
                    return f"**{char_count} / 4096**"

                # Update character count when the user stops typing
                input_textbox.change(
                    fn=update_char_count,
                    inputs=input_textbox,
                    outputs=char_count_text,
                )

                submit_button = gr.Button(
                    "Convert Text to Speech",
                    variant="primary",
                )
            with gr.Column(scale=1):
                output_audio = gr.Audio(label="Output Audio")

        # Define the event handler for the submit button with error handling
        def on_submit(
            input_text, model, voice, api_key, response_format, speed
        ):
            audio_file = tts(
                input_text, model, voice, api_key, response_format, speed
            )
            return audio_file

        # Trigger the conversion when the submit button is clicked
        submit_button.click(
            fn=on_submit,
            inputs=[
                input_textbox,
                model_dropdown,
                voice_dropdown,
                api_key_input,
                response_format_dropdown,
                speed_slider,
            ],
            outputs=output_audio,
        )

    # Launch the Gradio app with error display enabled
    demo.launch(show_error=True)


if __name__ == "__main__":
    main()