转录流式输入中的音频

本部分演示了如何将流式音频（如麦克风输入）转录为文字。

流式语音识别允许您将音频流式传输到 Speech-to-Text，并在音频处理的过程中实时接收流式语音识别的结果。另请参阅流式语音识别请求的音频限制。流式语音识别只能通过 gRPC 实现。

准备工作

Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

Enable the Speech-to-Text APIs.

Enable the APIs

Make sure that you have the following role or roles on the project: Cloud Speech Administrator

Check for the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.

3. In the Principal column, find all rows that identify you or a group that you're included in. To learn which groups you're included in, contact your administrator.

4. For all rows that specify or include you, check the Role column to see whether the list of roles includes the required roles.

Grant the roles

1. In the Google Cloud console, go to the IAM page.

   前往 IAM
2. 选择项目。
3. 点击 person_add 授予访问权限。

4. 在新的主账号字段中，输入您的用户标识符。 这通常是 Google 账号的电子邮件地址。

5. 在选择角色列表中，选择一个角色。
6. 如需授予其他角色，请点击 add 添加其他角色，然后添加其他各个角色。
7. 点击 Save（保存）。

Install the Google Cloud CLI.

如果您使用的是外部身份提供方 (IdP)，则必须先使用联合身份登录 gcloud CLI。

如需初始化 gcloud CLI，请运行以下命令：

gcloud init

In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

Go to project selector

Verify that billing is enabled for your Google Cloud project.

Enable the Speech-to-Text APIs.

Enable the APIs

Make sure that you have the following role or roles on the project: Cloud Speech Administrator

Check for the roles

1. In the Google Cloud console, go to the IAM page.

   Go to IAM
2. Select the project.

3. In the Principal column, find all rows that identify you or a group that you're included in. To learn which groups you're included in, contact your administrator.

4. For all rows that specify or include you, check the Role column to see whether the list of roles includes the required roles.

Grant the roles

1. In the Google Cloud console, go to the IAM page.

   前往 IAM
2. 选择项目。
3. 点击 person_add 授予访问权限。

4. 在新的主账号字段中，输入您的用户标识符。 这通常是 Google 账号的电子邮件地址。

5. 在选择角色列表中，选择一个角色。
6. 如需授予其他角色，请点击 add 添加其他角色，然后添加其他各个角色。
7. 点击 Save（保存）。

Install the Google Cloud CLI.

如果您使用的是外部身份提供方 (IdP)，则必须先使用联合身份登录 gcloud CLI。

如需初始化 gcloud CLI，请运行以下命令：

gcloud init

客户端库可以使用应用默认凭据轻松进行 Google API 身份验证，并向这些 API 发送请求。借助应用默认凭证，您可以在本地测试应用并部署它，无需更改底层代码。如需了解详情，请参阅使用客户端库时进行身份验证。

1. If you're using a local shell, then create local authentication credentials for your user account:

   gcloud auth application-default login

   You don't need to do this if you're using Cloud Shell.

   If an authentication error is returned, and you are using an external identity provider (IdP), confirm that you have signed in to the gcloud CLI with your federated identity.

此外，请确保您已安装客户端库。

对本地文件执行流式语音识别

以下是对本地音频文件执行流式语音识别的示例。数据流请求中发送的音频不得超过 25 KB。此限制适用于初始 StreamingRecognize 请求和数据流中每一条消息的大小。超出此限制时，系统会抛出错误。

Python

import os

from google.cloud.speech_v2 import SpeechClient
from google.cloud.speech_v2.types import cloud_speech as cloud_speech_types

PROJECT_ID = os.getenv("GOOGLE_CLOUD_PROJECT")


def transcribe_streaming_v2(
    stream_file: str,
) -> cloud_speech_types.StreamingRecognizeResponse:
    """Transcribes audio from an audio file stream using Google Cloud Speech-to-Text API.
    Args:
        stream_file (str): Path to the local audio file to be transcribed.
            Example: "resources/audio.wav"
    Returns:
        list[cloud_speech_types.StreamingRecognizeResponse]: A list of objects.
            Each response includes the transcription results for the corresponding audio segment.
    """
    # Instantiates a client
    client = SpeechClient()

    # Reads a file as bytes
    with open(stream_file, "rb") as f:
        audio_content = f.read()

    # In practice, stream should be a generator yielding chunks of audio data
    chunk_length = len(audio_content) // 5
    stream = [
        audio_content[start : start + chunk_length]
        for start in range(0, len(audio_content), chunk_length)
    ]
    audio_requests = (
        cloud_speech_types.StreamingRecognizeRequest(audio=audio) for audio in stream
    )

    recognition_config = cloud_speech_types.RecognitionConfig(
        auto_decoding_config=cloud_speech_types.AutoDetectDecodingConfig(),
        language_codes=["en-US"],
        model="long",
    )
    streaming_config = cloud_speech_types.StreamingRecognitionConfig(
        config=recognition_config
    )
    config_request = cloud_speech_types.StreamingRecognizeRequest(
        recognizer=f"projects/{PROJECT_ID}/locations/global/recognizers/_",
        streaming_config=streaming_config,
    )

    def requests(config: cloud_speech_types.RecognitionConfig, audio: list) -> list:
        yield config
        yield from audio

    # Transcribes the audio into text
    responses_iterator = client.streaming_recognize(
        requests=requests(config_request, audio_requests)
    )
    responses = []
    for response in responses_iterator:
        responses.append(response)
        for result in response.results:
            print(f"Transcript: {result.alternatives[0].transcript}")

    return responses

虽然您可以将本地音频文件流式传输到 Speech-to-Text API，但建议您执行同步音频识别。

清理

为避免因本页中使用的资源导致您的 Google Cloud 账号产生费用，请按照以下步骤操作。

1. Optional: Revoke the authentication credentials that you created, and delete the local credential file.

   gcloud auth application-default revoke

2. Optional: Revoke credentials from the gcloud CLI.

   gcloud auth revoke

控制台

In the Google Cloud console, go to the Manage resources page.

Go to Manage resources

In the project list, select the project that you want to delete, and then click Delete.

In the dialog, type the project ID, and then click Shut down to delete the project.

gcloud

In the Google Cloud console, go to the Manage resources page.

Go to Manage resources

In the project list, select the project that you want to delete, and then click Delete.

In the dialog, type the project ID, and then click Shut down to delete the project.

后续步骤

• 请参阅参考文档了解流式识别。
• 练习转写短音频文件。
• 了解如何转录长音频文件。
• 使用 Chirp 转录音频文件。
• 如需了解关于最佳性能、准确度和其他方面的提示，请参阅最佳实践文档。