Transcribing with the AWS SDKs
You can use SDKs for both batch and streaming transcriptions. If you're transcribing a media
file located in an Amazon S3 bucket, you're performing a batch transcription. If you're
transcribing a real-time stream of audio data, you're performing a streaming transcription.
For a list of the programming languages you can use with Amazon Transcribe, see
Supported programming languages. Note that streaming
transcriptions are not supported with all AWS SDKs. To view supported media formats
and other media requirements and constraints, see Data input and output.
For more information on all available AWS SDKs and builder tools, refer to
Tools to Build on AWS.
You can create batch transcriptions using the URI of a media file located in an Amazon S3
bucket. If you're unsure how to create an Amazon S3 bucket or upload your file, refer to
Create your first S3
bucket and Upload an object
to your bucket.
- Java
-
import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.transcribe.TranscribeClient;
import software.amazon.awssdk.services.transcribe.model.*;
import software.amazon.awssdk.services.transcribestreaming.model.LanguageCode;
public class TranscribeDemoApp {
private static final Region REGION = Region.US_WEST_2;
private static TranscribeClient client;
public static void main(String args[]) {
client = TranscribeClient.builder()
.credentialsProvider(getCredentials())
.region(REGION)
.build();
String transcriptionJobName = "my-first-transcription-job";
String mediaType = "flac"; // can be other types
Media myMedia = Media.builder()
.mediaFileUri("s3://DOC-EXAMPLE-BUCKET/my-input-files/my-media-file.flac")
.build();
String outputS3BucketName = "s3://DOC-EXAMPLE-BUCKET";
// Create the transcription job request
StartTranscriptionJobRequest request = StartTranscriptionJobRequest.builder()
.transcriptionJobName(transcriptionJobName)
.languageCode(LanguageCode.EN_US.toString())
.mediaSampleRateHertz(16000)
.mediaFormat(mediaType)
.media(myMedia)
.outputBucketName(outputS3BucketName)
.build();
// send the request to start the transcription job
StartTranscriptionJobResponse startJobResponse = client.startTranscriptionJob(request);
System.out.println("Created the transcription job");
System.out.println(startJobResponse.transcriptionJob());
// Create the get job request
GetTranscriptionJobRequest getJobRequest = GetTranscriptionJobRequest.builder()
.transcriptionJobName(transcriptionJobName)
.build();
// send the request to get the transcription job including the job status
GetTranscriptionJobResponse getJobResponse = client.getTranscriptionJob(getJobRequest);
System.out.println("Get the transcription job request");
System.out.println(getJobResponse.transcriptionJob());
}
private static AwsCredentialsProvider getCredentials() {
return DefaultCredentialsProvider.create();
}
}
- JavaScript
-
const { TranscribeClient, StartTranscriptionJobCommand } = require("@aws-sdk/client-transcribe"); // CommonJS import
const region = "us-west-2";
const credentials = {
"accessKeyId": "",
"secretAccessKey": "",
};
const input = {
TranscriptionJobName: "my-first-transcription-job",
LanguageCode: "en-US",
Media: {
MediaFileUri: "s3://DOC-EXAMPLE-BUCKET/my-input-files/my-media-file.flac"
},
OutputBucketName: "DOC-EXAMPLE-BUCKET",
};
async function startTranscriptionRequest() {
const transcribeConfig = {
region,
credentials
};
const transcribeClient = new TranscribeClient(transcribeConfig);
const transcribeCommand = new StartTranscriptionJobCommand(input);
try {
const transcribeResponse = await transcribeClient.send(transcribeCommand);
console.log("Transcription job created, the details:");
console.log(transcribeResponse.TranscriptionJob);
} catch(err) {
console.log(err);
}
}
startTranscriptionRequest();
- Python
-
import time
import boto3
def transcribe_file(job_name, file_uri, transcribe_client):
transcribe_client.start_transcription_job(
TranscriptionJobName = job_name,
Media = {
'MediaFileUri': file_uri
},
MediaFormat = 'flac',
LanguageCode = 'en-US'
)
max_tries = 60
while max_tries > 0:
max_tries -= 1
job = transcribe_client.get_transcription_job(TranscriptionJobName = job_name)
job_status = job['TranscriptionJob']['TranscriptionJobStatus']
if job_status in ['COMPLETED', 'FAILED']:
print(f"Job {job_name} is {job_status}.")
if job_status == 'COMPLETED':
print(
f"Download the transcript from\n"
f"\t{job['TranscriptionJob']['Transcript']['TranscriptFileUri']}.")
break
else:
print(f"Waiting for {job_name}. Current status is {job_status}.")
time.sleep(10)
def main():
transcribe_client = boto3.client('transcribe', region_name = 'us-west-2')
file_uri = 's3://DOC-EXAMPLE-BUCKET/my-input-files/my-media-file.flac'
transcribe_file('Example-job', file_uri, transcribe_client)
if __name__ == '__main__':
main()
You can create streaming transcriptions using a streamed media file or a live media
stream.
Note that the standard AWS SDK for Python (Boto3) is not supported for Amazon Transcribe
streaming. To start a streaming transcription using Python, use this
async Python
SDK for Amazon Transcribe.
- Java
-
The following example is a Java program that transcribes streaming audio.
To run this example, note the following:
See also: Retry
client for Amazon Transcribe streaming (Java SDK). This code manages the connection to
Amazon Transcribe and retries sending data when there are errors on the connection. For example, if
there is a transient error on the network, this client resends the request that
failed.
public class TranscribeStreamingDemoApp {
private static final Region REGION = Region.US_WEST_2;
private static TranscribeStreamingAsyncClient client;
public static void main(String args[]) throws URISyntaxException, ExecutionException, InterruptedException, LineUnavailableException {
client = TranscribeStreamingAsyncClient.builder()
.credentialsProvider(getCredentials())
.region(REGION)
.build();
CompletableFuture<Void> result = client.startStreamTranscription(getRequest(16_000),
new AudioStreamPublisher(getStreamFromMic()),
getResponseHandler());
result.get();
client.close();
}
private static InputStream getStreamFromMic() throws LineUnavailableException {
// Signed PCM AudioFormat with 16,000 Hz, 16 bit sample size, mono
int sampleRate = 16000;
AudioFormat format = new AudioFormat(sampleRate, 16, 1, true, false);
DataLine.Info info = new DataLine.Info(TargetDataLine.class, format);
if (!AudioSystem.isLineSupported(info)) {
System.out.println("Line not supported");
System.exit(0);
}
TargetDataLine line = (TargetDataLine) AudioSystem.getLine(info);
line.open(format);
line.start();
InputStream audioStream = new AudioInputStream(line);
return audioStream;
}
private static AwsCredentialsProvider getCredentials() {
return DefaultCredentialsProvider.create();
}
private static StartStreamTranscriptionRequest getRequest(Integer mediaSampleRateHertz) {
return StartStreamTranscriptionRequest.builder()
.languageCode(LanguageCode.EN_US.toString())
.mediaEncoding(MediaEncoding.PCM)
.mediaSampleRateHertz(mediaSampleRateHertz)
.build();
}
private static StartStreamTranscriptionResponseHandler getResponseHandler() {
return StartStreamTranscriptionResponseHandler.builder()
.onResponse(r -> {
System.out.println("Received Initial response");
})
.onError(e -> {
System.out.println(e.getMessage());
StringWriter sw = new StringWriter();
e.printStackTrace(new PrintWriter(sw));
System.out.println("Error Occurred: " + sw.toString());
})
.onComplete(() -> {
System.out.println("=== All records stream successfully ===");
})
.subscriber(event -> {
List<Result> results = ((TranscriptEvent) event).transcript().results();
if (results.size() > 0) {
if (!results.get(0).alternatives().get(0).transcript().isEmpty()) {
System.out.println(results.get(0).alternatives().get(0).transcript());
}
}
})
.build();
}
private InputStream getStreamFromFile(String myMediaFileName) {
try {
File inputFile = new File(getClass().getClassLoader().getResource(myMediaFileName).getFile());
InputStream audioStream = new FileInputStream(inputFile);
return audioStream;
} catch (FileNotFoundException e) {
throw new RuntimeException(e);
}
}
private static class AudioStreamPublisher implements Publisher<AudioStream> {
private final InputStream inputStream;
private static Subscription currentSubscription;
private AudioStreamPublisher(InputStream inputStream) {
this.inputStream = inputStream;
}
@Override
public void subscribe(Subscriber<? super AudioStream> s) {
if (this.currentSubscription == null) {
this.currentSubscription = new SubscriptionImpl(s, inputStream);
} else {
this.currentSubscription.cancel();
this.currentSubscription = new SubscriptionImpl(s, inputStream);
}
s.onSubscribe(currentSubscription);
}
}
public static class SubscriptionImpl implements Subscription {
private static final int CHUNK_SIZE_IN_BYTES = 1024 * 1;
private final Subscriber<? super AudioStream> subscriber;
private final InputStream inputStream;
private ExecutorService executor = Executors.newFixedThreadPool(1);
private AtomicLong demand = new AtomicLong(0);
SubscriptionImpl(Subscriber<? super AudioStream> s, InputStream inputStream) {
this.subscriber = s;
this.inputStream = inputStream;
}
@Override
public void request(long n) {
if (n <= 0) {
subscriber.onError(new IllegalArgumentException("Demand must be positive"));
}
demand.getAndAdd(n);
executor.submit(() -> {
try {
do {
ByteBuffer audioBuffer = getNextEvent();
if (audioBuffer.remaining() > 0) {
AudioEvent audioEvent = audioEventFromBuffer(audioBuffer);
subscriber.onNext(audioEvent);
} else {
subscriber.onComplete();
break;
}
} while (demand.decrementAndGet() > 0);
} catch (Exception e) {
subscriber.onError(e);
}
});
}
@Override
public void cancel() {
executor.shutdown();
}
private ByteBuffer getNextEvent() {
ByteBuffer audioBuffer = null;
byte[] audioBytes = new byte[CHUNK_SIZE_IN_BYTES];
int len = 0;
try {
len = inputStream.read(audioBytes);
if (len <= 0) {
audioBuffer = ByteBuffer.allocate(0);
} else {
audioBuffer = ByteBuffer.wrap(audioBytes, 0, len);
}
} catch (IOException e) {
throw new UncheckedIOException(e);
}
return audioBuffer;
}
private AudioEvent audioEventFromBuffer(ByteBuffer bb) {
return AudioEvent.builder()
.audioChunk(SdkBytes.fromByteBuffer(bb))
.build();
}
}
}
- JavaScript
-
const {
TranscribeStreamingClient,
StartStreamTranscriptionCommand,
} = require("@aws-sdk/client-transcribe-streaming");
const { createReadStream } = require("fs");
const { join } = require("path");
const audio = createReadStream(join(__dirname, "my-media-file.flac"), { highWaterMark: 1024 * 16});
const LanguageCode = "en-US";
const MediaEncoding = "pcm";
const MediaSampleRateHertz = "16000";
const credentials = {
"accessKeyId": "",
"secretAccessKey": "",
};
async function startRequest() {
const client = new TranscribeStreamingClient({
region: "us-west-2",
credentials
});
const params = {
LanguageCode,
MediaEncoding,
MediaSampleRateHertz,
AudioStream: (async function* () {
for await (const chunk of audio) {
yield {AudioEvent: {AudioChunk: chunk}};
}
})(),
};
const command = new StartStreamTranscriptionCommand(params);
// Send transcription request
const response = await client.send(command);
// Start to print response
try {
for await (const event of response.TranscriptResultStream) {
console.log(JSON.stringify(event));
}
} catch(err) {
console.log("error")
console.log(err)
}
}
startRequest();
- Python
-
The following example is a Python program that transcribes streaming audio.
To run this example, note the following:
import asyncio
# This example uses aiofile for asynchronous file reads.
# It's not a dependency of the project but can be installed
# with `pip install aiofile`.
import aiofile
from amazon_transcribe.client import TranscribeStreamingClient
from amazon_transcribe.handlers import TranscriptResultStreamHandler
from amazon_transcribe.model import TranscriptEvent
"""
Here's an example of a custom event handler you can extend to
process the returned transcription results as needed. This
handler will simply print the text out to your interpreter.
"""
class MyEventHandler(TranscriptResultStreamHandler):
async def handle_transcript_event(self, transcript_event: TranscriptEvent):
# This handler can be implemented to handle transcriptions as needed.
# Here's an example to get started.
results = transcript_event.transcript.results
for result in results:
for alt in result.alternatives:
print(alt.transcript)
async def basic_transcribe():
# Set up our client with your chosen Region
client = TranscribeStreamingClient(region = "us-west-2")
# Start transcription to generate async stream
stream = await client.start_stream_transcription(
language_code = "en-US",
media_sample_rate_hz = 16000,
media_encoding = "pcm",
)
async def write_chunks():
# NOTE: For pre-recorded files longer than 5 minutes, the sent audio
# chunks should be rate limited to match the real-time bitrate of the
# audio stream to avoid signing issues.
async with aiofile.AIOFile('filepath/my-media-file.flac', 'rb') as afp:
reader = aiofile.Reader(afp, chunk_size = 1024 * 16)
async for chunk in reader:
await stream.input_stream.send_audio_event(audio_chunk = chunk)
await stream.input_stream.end_stream()
# Instantiate our handler and start processing events
handler = MyEventHandler(stream.output_stream)
await asyncio.gather(write_chunks(), handler.handle_events())
loop = asyncio.get_event_loop()
loop.run_until_complete(basic_transcribe())
loop.close()
- C++
-
Refer to the Code examples chapter for the streaming C++ SDK example.
AWS software development kits (SDKs) are available for many popular programming languages. Each SDK provides an API, code examples, and documentation that
make it easier for developers to build applications in their preferred language.
For examples specific to this service, see Code examples for Amazon Transcribe using AWS SDKs.
Can't find what you need? Request a code example by using the Provide feedback link at the bottom of this page.
