除了有語音轉文字的服務，
GCP 也提供了文字轉語音的服務。
可以想像過去我們在遊戲或是動畫中需要很多配音員，
現在我們只要有文字，就能生成該角色的聲音。

首先是安裝:

pip install  google-cloud-texttospeech

下面程式碼，是使用的方式:

import os
from google.cloud import texttospeech

credential_path = "cred.json"
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = credential_path

# Instantiates a client
client = texttospeech.TextToSpeechClient()

# Set the text input to be synthesized
synthesis_input = texttospeech.SynthesisInput(text="Hello, World!")

# Build the voice request, select the language code ("en-US") and the ssml
# voice gender ("neutral")
voice = texttospeech.VoiceSelectionParams(
    language_code="en-US", ssml_gender=texttospeech.SsmlVoiceGender.NEUTRAL
)

# Select the type of audio file you want returned
audio_config = texttospeech.AudioConfig(
    audio_encoding=texttospeech.AudioEncoding.MP3
)

# Perform the text-to-speech request on the text input with the selected
# voice parameters and audio file type
response = client.synthesize_speech(
    input=synthesis_input, voice=voice, audio_config=audio_config
)

with open("output.mp3", "wb") as out:
    out.write(response.audio_content)
    print('Audio content written to file "output.mp3"')

synthesis_input為輸入的台詞，
而texttospeech.VoiceSelectionParams參數的部分，為聲音的調整，
可以從下面的function列出可選用的語音參數:

import os

credential_path = "cred.json"
os.environ['GOOGLE_APPLICATION_CREDENTIALS'] = credential_path

def list_voices():
    """Lists the available voices."""
    from google.cloud import texttospeech

    client = texttospeech.TextToSpeechClient()

    # Performs the list voices request
    voices = client.list_voices()

    for voice in voices.voices:
        # Display the voice's name. Example: tpc-vocoded
        print(f"Name: {voice.name}")

        # Display the supported language codes for this voice. Example: "en-US"
        for language_code in voice.language_codes:
            print(f"Supported language: {language_code}")

        ssml_gender = texttospeech.SsmlVoiceGender(voice.ssml_gender)

        # Display the SSML Voice Gender
        print(f"SSML Voice Gender: {ssml_gender.name}")

        # Display the natural sample rate hertz for this voice. Example: 24000
        print(f"Natural Sample Rate Hertz: {voice.natural_sample_rate_hertz}\n")

list_voices()

選定之後，我們可以從官網看一下VoiceSelectionParams的參數:
https://cloud.google.com/text-to-speech/docs/reference/rpc/google.cloud.texttospeech.v1#voiceselectionparams

可以發現給定language_code、name、ssml_gender可以完成設定。

而audio_encoding選擇格式為mp3，其他格式也能從文件做查詢:
https://cloud.google.com/text-to-speech/docs/reference/rpc/google.cloud.texttospeech.v1#google.cloud.texttospeech.v1.AudioEncoding

儲存mp3，完成這天的進度。

價格的話也是不貴，免費空間也是很大的，可以從圖片中做參考: