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。
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。发送至 API 的所有流式传输请求不能超过 10 MB。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。
Go
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Go API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
import (
"context"
"flag"
"fmt"
"io"
"log"
"os"
"path/filepath"
speech "cloud.google.com/go/speech/apiv1"
"cloud.google.com/go/speech/apiv1/speechpb"
)
func main() {
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s <AUDIOFILE>\n", filepath.Base(os.Args[0]))
fmt.Fprintf(os.Stderr, "<AUDIOFILE> must be a path to a local audio file. Audio file must be a 16-bit signed little-endian encoded with a sample rate of 16000.\n")
}
flag.Parse()
if len(flag.Args()) != 1 {
log.Fatal("Please pass path to your local audio file as a command line argument")
}
audioFile := flag.Arg(0)
ctx := context.Background()
client, err := speech.NewClient(ctx)
if err != nil {
log.Fatal(err)
}
stream, err := client.StreamingRecognize(ctx)
if err != nil {
log.Fatal(err)
}
// Send the initial configuration message.
if err := stream.Send(&speechpb.StreamingRecognizeRequest{
StreamingRequest: &speechpb.StreamingRecognizeRequest_StreamingConfig{
StreamingConfig: &speechpb.StreamingRecognitionConfig{
Config: &speechpb.RecognitionConfig{
Encoding: speechpb.RecognitionConfig_LINEAR16,
SampleRateHertz: 16000,
LanguageCode: "en-US",
},
},
},
}); err != nil {
log.Fatal(err)
}
f, err := os.Open(audioFile)
if err != nil {
log.Fatal(err)
}
defer f.Close()
go func() {
buf := make([]byte, 1024)
for {
n, err := f.Read(buf)
if n > 0 {
if err := stream.Send(&speechpb.StreamingRecognizeRequest{
StreamingRequest: &speechpb.StreamingRecognizeRequest_AudioContent{
AudioContent: buf[:n],
},
}); err != nil {
log.Printf("Could not send audio: %v", err)
}
}
if err == io.EOF {
// Nothing else to pipe, close the stream.
if err := stream.CloseSend(); err != nil {
log.Fatalf("Could not close stream: %v", err)
}
return
}
if err != nil {
log.Printf("Could not read from %s: %v", audioFile, err)
continue
}
}
}()
for {
resp, err := stream.Recv()
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("Cannot stream results: %v", err)
}
if err := resp.Error; err != nil {
log.Fatalf("Could not recognize: %v", err)
}
for _, result := range resp.Results {
fmt.Printf("Result: %+v\n", result)
}
}
}
Java
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Java API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
/**
* Performs streaming speech recognition on raw PCM audio data.
*
* @param fileName the path to a PCM audio file to transcribe.
*/
public static void streamingRecognizeFile(String fileName) throws Exception, IOException {
Path path = Paths.get(fileName);
byte[] data = Files.readAllBytes(path);
// Instantiates a client with GOOGLE_APPLICATION_CREDENTIALS
try (SpeechClient speech = SpeechClient.create()) {
// Configure request with local raw PCM audio
RecognitionConfig recConfig =
RecognitionConfig.newBuilder()
.setEncoding(AudioEncoding.LINEAR16)
.setLanguageCode("en-US")
.setSampleRateHertz(16000)
.setModel("default")
.build();
StreamingRecognitionConfig config =
StreamingRecognitionConfig.newBuilder().setConfig(recConfig).build();
class ResponseApiStreamingObserver<T> implements ApiStreamObserver<T> {
private final SettableFuture<List<T>> future = SettableFuture.create();
private final List<T> messages = new java.util.ArrayList<T>();
@Override
public void onNext(T message) {
messages.add(message);
}
@Override
public void onError(Throwable t) {
future.setException(t);
}
@Override
public void onCompleted() {
future.set(messages);
}
// Returns the SettableFuture object to get received messages / exceptions.
public SettableFuture<List<T>> future() {
return future;
}
}
ResponseApiStreamingObserver<StreamingRecognizeResponse> responseObserver =
new ResponseApiStreamingObserver<>();
BidiStreamingCallable<StreamingRecognizeRequest, StreamingRecognizeResponse> callable =
speech.streamingRecognizeCallable();
ApiStreamObserver<StreamingRecognizeRequest> requestObserver =
callable.bidiStreamingCall(responseObserver);
// The first request must **only** contain the audio configuration:
requestObserver.onNext(
StreamingRecognizeRequest.newBuilder().setStreamingConfig(config).build());
// Subsequent requests must **only** contain the audio data.
requestObserver.onNext(
StreamingRecognizeRequest.newBuilder()
.setAudioContent(ByteString.copyFrom(data))
.build());
// Mark transmission as completed after sending the data.
requestObserver.onCompleted();
List<StreamingRecognizeResponse> responses = responseObserver.future().get();
for (StreamingRecognizeResponse response : responses) {
// For streaming recognize, the results list has one is_final result (if available) followed
// by a number of in-progress results (if iterim_results is true) for subsequent utterances.
// Just print the first result here.
StreamingRecognitionResult result = response.getResultsList().get(0);
// There can be several alternative transcripts for a given chunk of speech. Just use the
// first (most likely) one here.
SpeechRecognitionAlternative alternative = result.getAlternativesList().get(0);
System.out.printf("Transcript : %s\n", alternative.getTranscript());
}
}
}Node.js
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Node.js API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
const fs = require('fs');
// Imports the Google Cloud client library
const speech = require('@google-cloud/speech');
// Creates a client
const client = new speech.SpeechClient();
/**
* TODO(developer): Uncomment the following lines before running the sample.
*/
// const filename = 'Local path to audio file, e.g. /path/to/audio.raw';
// const encoding = 'Encoding of the audio file, e.g. LINEAR16';
// const sampleRateHertz = 16000;
// const languageCode = 'BCP-47 language code, e.g. en-US';
const request = {
config: {
encoding: encoding,
sampleRateHertz: sampleRateHertz,
languageCode: languageCode,
},
interimResults: false, // If you want interim results, set this to true
};
// Stream the audio to the Google Cloud Speech API
const recognizeStream = client
.streamingRecognize(request)
.on('error', console.error)
.on('data', data => {
console.log(
`Transcription: ${data.results[0].alternatives[0].transcript}`
);
});
// Stream an audio file from disk to the Speech API, e.g. "./resources/audio.raw"
fs.createReadStream(filename).pipe(recognizeStream);Python
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Python API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
def transcribe_streaming(stream_file: str) -> speech.RecognitionConfig:
"""Streams transcription of the given audio file."""
client = speech.SpeechClient()
with open(stream_file, "rb") as audio_file:
content = audio_file.read()
# In practice, stream should be a generator yielding chunks of audio data.
stream = [content]
requests = (
speech.StreamingRecognizeRequest(audio_content=chunk) for chunk in stream
)
config = speech.RecognitionConfig(
encoding=speech.RecognitionConfig.AudioEncoding.LINEAR16,
sample_rate_hertz=16000,
language_code="en-US",
)
streaming_config = speech.StreamingRecognitionConfig(config=config)
# streaming_recognize returns a generator.
responses = client.streaming_recognize(
config=streaming_config,
requests=requests,
)
for response in responses:
# Once the transcription has settled, the first result will contain the
# is_final result. The other results will be for subsequent portions of
# the audio.
for result in response.results:
print(f"Finished: {result.is_final}")
print(f"Stability: {result.stability}")
alternatives = result.alternatives
# The alternatives are ordered from most likely to least.
for alternative in alternatives:
print(f"Confidence: {alternative.confidence}")
print(f"Transcript: {alternative.transcript}")
其他语言
C#：请按照客户端库页面上的 C# 设置说明操作，然后访问 .NET 的 Speech-to-Text 参考文档。
PHP：请按照客户端库页面上的 PHP 设置说明 操作，然后访问 PHP 的 Speech-to-Text 参考文档。
Ruby：请按照客户端库页面上的 Ruby 设置说明操作，然后访问 Ruby 的 Speech-to-Text 参考文档。
虽然您可以将本地音频文件流式传输到 Speech-to-Text API，但建议您执行同步或异步音频识别以便批量获得处理结果。
对音频流执行流式语音识别
Speech-to-Text 也可以对实时流式音频执行识别。
以下示例对从麦克风接收到的音频流执行流式语音识别：
Go
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Go API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
import (
"context"
"fmt"
"io"
"log"
"os"
speech "cloud.google.com/go/speech/apiv1"
"cloud.google.com/go/speech/apiv1/speechpb"
)
func main() {
ctx := context.Background()
client, err := speech.NewClient(ctx)
if err != nil {
log.Fatal(err)
}
stream, err := client.StreamingRecognize(ctx)
if err != nil {
log.Fatal(err)
}
// Send the initial configuration message.
if err := stream.Send(&speechpb.StreamingRecognizeRequest{
StreamingRequest: &speechpb.StreamingRecognizeRequest_StreamingConfig{
StreamingConfig: &speechpb.StreamingRecognitionConfig{
Config: &speechpb.RecognitionConfig{
Encoding: speechpb.RecognitionConfig_LINEAR16,
SampleRateHertz: 16000,
LanguageCode: "en-US",
},
},
},
}); err != nil {
log.Fatal(err)
}
go func() {
// Pipe stdin to the API.
buf := make([]byte, 1024)
for {
n, err := os.Stdin.Read(buf)
if n > 0 {
if err := stream.Send(&speechpb.StreamingRecognizeRequest{
StreamingRequest: &speechpb.StreamingRecognizeRequest_AudioContent{
AudioContent: buf[:n],
},
}); err != nil {
log.Printf("Could not send audio: %v", err)
}
}
if err == io.EOF {
// Nothing else to pipe, close the stream.
if err := stream.CloseSend(); err != nil {
log.Fatalf("Could not close stream: %v", err)
}
return
}
if err != nil {
log.Printf("Could not read from stdin: %v", err)
continue
}
}
}()
for {
resp, err := stream.Recv()
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("Cannot stream results: %v", err)
}
if err := resp.Error; err != nil {
// Workaround while the API doesn't give a more informative error.
if err.Code == 3 || err.Code == 11 {
log.Print("WARNING: Speech recognition request exceeded limit of 60 seconds.")
}
log.Fatalf("Could not recognize: %v", err)
}
for _, result := range resp.Results {
fmt.Printf("Result: %+v\n", result)
}
}
}
Python
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Python API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
import queue
import re
import sys
from google.cloud import speech
import pyaudio
# Audio recording parameters
RATE = 16000
CHUNK = int(RATE / 10) # 100ms
class MicrophoneStream:
"""Opens a recording stream as a generator yielding the audio chunks."""
def __init__(self: object, rate: int = RATE, chunk: int = CHUNK) -> None:
"""The audio -- and generator -- is guaranteed to be on the main thread."""
self._rate = rate
self._chunk = chunk
# Create a thread-safe buffer of audio data
self._buff = queue.Queue()
self.closed = True
def __enter__(self: object) -> object:
self._audio_interface = pyaudio.PyAudio()
self._audio_stream = self._audio_interface.open(
format=pyaudio.paInt16,
# The API currently only supports 1-channel (mono) audio
# https://goo.gl/z757pE
channels=1,
rate=self._rate,
input=True,
frames_per_buffer=self._chunk,
# Run the audio stream asynchronously to fill the buffer object.
# This is necessary so that the input device's buffer doesn't
# overflow while the calling thread makes network requests, etc.
stream_callback=self._fill_buffer,
)
self.closed = False
return self
def __exit__(
self: object,
type: object,
value: object,
traceback: object,
) -> None:
"""Closes the stream, regardless of whether the connection was lost or not."""
self._audio_stream.stop_stream()
self._audio_stream.close()
self.closed = True
# Signal the generator to terminate so that the client's
# streaming_recognize method will not block the process termination.
self._buff.put(None)
self._audio_interface.terminate()
def _fill_buffer(
self: object,
in_data: object,
frame_count: int,
time_info: object,
status_flags: object,
) -> object:
"""Continuously collect data from the audio stream, into the buffer.
Args:
in_data: The audio data as a bytes object
frame_count: The number of frames captured
time_info: The time information
status_flags: The status flags
Returns:
The audio data as a bytes object
"""
self._buff.put(in_data)
return None, pyaudio.paContinue
def generator(self: object) -> object:
"""Generates audio chunks from the stream of audio data in chunks.
Args:
self: The MicrophoneStream object
Returns:
A generator that outputs audio chunks.
"""
while not self.closed:
# Use a blocking get() to ensure there's at least one chunk of
# data, and stop iteration if the chunk is None, indicating the
# end of the audio stream.
chunk = self._buff.get()
if chunk is None:
return
data = [chunk]
# Now consume whatever other data's still buffered.
while True:
try:
chunk = self._buff.get(block=False)
if chunk is None:
return
data.append(chunk)
except queue.Empty:
break
yield b"".join(data)
def listen_print_loop(responses: object) -> str:
"""Iterates through server responses and prints them.
The responses passed is a generator that will block until a response
is provided by the server.
Each response may contain multiple results, and each result may contain
multiple alternatives; for details, see https://goo.gl/tjCPAU. Here we
print only the transcription for the top alternative of the top result.
In this case, responses are provided for interim results as well. If the
response is an interim one, print a line feed at the end of it, to allow
the next result to overwrite it, until the response is a final one. For the
final one, print a newline to preserve the finalized transcription.
Args:
responses: List of server responses
Returns:
The transcribed text.
"""
num_chars_printed = 0
for response in responses:
if not response.results:
continue
# The `results` list is consecutive. For streaming, we only care about
# the first result being considered, since once it's `is_final`, it
# moves on to considering the next utterance.
result = response.results[0]
if not result.alternatives:
continue
# Display the transcription of the top alternative.
transcript = result.alternatives[0].transcript
# Display interim results, but with a carriage return at the end of the
# line, so subsequent lines will overwrite them.
#
# If the previous result was longer than this one, we need to print
# some extra spaces to overwrite the previous result
overwrite_chars = " " * (num_chars_printed - len(transcript))
if not result.is_final:
sys.stdout.write(transcript + overwrite_chars + "\r")
sys.stdout.flush()
num_chars_printed = len(transcript)
else:
print(transcript + overwrite_chars)
# Exit recognition if any of the transcribed phrases could be
# one of our keywords.
if re.search(r"\b(exit|quit)\b", transcript, re.I):
print("Exiting..")
break
num_chars_printed = 0
return transcript
def main() -> None:
"""Transcribe speech from audio file."""
# See http://g.co/cloud/speech/docs/languages
# for a list of supported languages.
language_code = "en-US" # a BCP-47 language tag
client = speech.SpeechClient()
config = speech.RecognitionConfig(
encoding=speech.RecognitionConfig.AudioEncoding.LINEAR16,
sample_rate_hertz=RATE,
language_code=language_code,
)
streaming_config = speech.StreamingRecognitionConfig(
config=config, interim_results=True
)
with MicrophoneStream(RATE, CHUNK) as stream:
audio_generator = stream.generator()
requests = (
speech.StreamingRecognizeRequest(audio_content=content)
for content in audio_generator
)
responses = client.streaming_recognize(streaming_config, requests)
# Now, put the transcription responses to use.
listen_print_loop(responses)
if __name__ == "__main__":
main()Java
如需了解如何安装和使用 Speech-to-Text 客户端库，请参阅 Speech-to-Text 客户端库。如需了解详情，请参阅 Speech-to-Text Java API 参考文档。
如需向 Speech-to-Text 进行身份验证，请设置应用默认凭据。 如需了解详情，请参阅为本地开发环境设置身份验证。
/** Performs microphone streaming speech recognition with a duration of 1 minute. */
public static void streamingMicRecognize() throws Exception {
ResponseObserver<StreamingRecognizeResponse> responseObserver = null;
try (SpeechClient client = SpeechClient.create()) {
responseObserver =
new ResponseObserver<StreamingRecognizeResponse>() {
ArrayList<StreamingRecognizeResponse> responses = new ArrayList<>();
public void onStart(StreamController controller) {}
public void onResponse(StreamingRecognizeResponse response) {
responses.add(response);
}
public void onComplete() {
for (StreamingRecognizeResponse response : responses) {
StreamingRecognitionResult result = response.getResultsList().get(0);
SpeechRecognitionAlternative alternative = result.getAlternativesList().get(0);
System.out.printf("Transcript : %s\n", alternative.getTranscript());
}
}
public void onError(Throwable t) {
System.out.println(t);
}
};
ClientStream<StreamingRecognizeRequest> clientStream =
client.streamingRecognizeCallable().splitCall(responseObserver);
RecognitionConfig recognitionConfig =
RecognitionConfig.newBuilder()
.setEncoding(RecognitionConfig.AudioEncoding.LINEAR16)
.setLanguageCode("en-US")
.setSampleRateHertz(16000)
.build();
StreamingRecognitionConfig streamingRecognitionConfig =
StreamingRecognitionConfig.newBuilder().setConfig(recognitionConfig).build();
StreamingRecognizeRequest request =
StreamingRecognizeRequest.newBuilder()
.setStreamingConfig(streamingRecognitionConfig)
.build(); // The first request in a streaming call has to be a config
clientStream.send(request);
// SampleRate:16000Hz, SampleSizeInBits: 16, Number of channels: 1, Signed: true,
// bigEndian: false
AudioFormat audioFormat = new AudioFormat(16000, 16, 1, true, false);
DataLine.Info targetInfo =
new Info(
TargetDataLine.class,
audioFormat); // Set the system information to read from the microphone audio stream
if (!AudioSystem.isLineSupported(targetInfo)) {
System.out.println("Microphone not supported");
System.exit(0);
}
// Target data line captures the audio stream the microphone produces.
TargetDataLine targetDataLine = (TargetDataLine) AudioSystem.getLine(targetInfo);
targetDataLine.open(audioFormat);
targetDataLine.start();
System.out.println("Start speaking");
long startTime = System.currentTimeMillis();
// Audio Input Stream
AudioInputStream audio = new AudioInputStream(targetDataLine);
while (true) {
long estimatedTime = System.currentTimeMillis() - startTime;
byte[] data = new byte[6400];
audio.read(data);
if (estimatedTime > 60000) { // 60 seconds
System.out.println("Stop speaking.");
targetDataLine.stop();
targetDataLine.close();
break;
}
request =
StreamingRecognizeRequest.newBuilder()
.setAudioContent(ByteString.copyFrom(data))
.build();
clientStream.send(request);
}
} catch (Exception e) {
System.out.println(e);
}
responseObserver.onComplete();
}Node.js
此示例要求您安装 SoX，并确保其在 $PATH 中可用。
- 对于 Mac OS：
brew install sox。 - 对于大多数 Linux 发行版：
sudo apt-get install sox libsox-fmt-all。 - 对于 Windows：请下载二进制文件。
如需详细了解如何安装和创建 Speech-to-Text 客户端，请参阅 Speech-to-Text 客户端库。
const recorder = require('node-record-lpcm16');
// Imports the Google Cloud client library
const speech = require('@google-cloud/speech');
// Creates a client
const client = new speech.SpeechClient();
/**
* TODO(developer): Uncomment the following lines before running the sample.
*/
// const encoding = 'Encoding of the audio file, e.g. LINEAR16';
// const sampleRateHertz = 16000;
// const languageCode = 'BCP-47 language code, e.g. en-US';
const request = {
config: {
encoding: encoding,
sampleRateHertz: sampleRateHertz,
languageCode: languageCode,
},
interimResults: false, // If you want interim results, set this to true
};
// Create a recognize stream
const recognizeStream = client
.streamingRecognize(request)
.on('error', console.error)
.on('data', data =>
process.stdout.write(
data.results[0] && data.results[0].alternatives[0]
? `Transcription: ${data.results[0].alternatives[0].transcript}\n`
: '\n\nReached transcription time limit, press Ctrl+C\n'
)
);
// Start recording and send the microphone input to the Speech API.
// Ensure SoX is installed, see https://www.npmjs.com/package/node-record-lpcm16#dependencies
recorder
.record({
sampleRateHertz: sampleRateHertz,
threshold: 0,
// Other options, see https://www.npmjs.com/package/node-record-lpcm16#options
verbose: false,
recordProgram: 'rec', // Try also "arecord" or "sox"
silence: '10.0',
})
.stream()
.on('error', console.error)
.pipe(recognizeStream);
console.log('Listening, press Ctrl+C to stop.');其他语言
C#：请按照客户端库页面上的 C# 设置说明操作，然后访问 .NET 的 Speech-to-Text 参考文档。
PHP：请按照客户端库页面上的 PHP 设置说明 操作，然后访问 PHP 的 Speech-to-Text 参考文档。
Ruby：请按照客户端库页面上的 Ruby 设置说明操作，然后访问 Ruby 的 Speech-to-Text 参考文档。
后续步骤
- 了解如何无休止转录音频流
自行试用
如果您是 Google Cloud 新手，请创建一个账号来评估 Speech-to-Text 在实际场景中的表现。新客户还可获享 $300 赠金，用于运行、测试和部署工作负载。
免费试用 Speech-to-Text