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StreamingExample.java

StreamingExample.java transcribes streaming audio from your computer's microphone or a file upload. The output is presented on your computer's standard output.

/** * COPYRIGHT: * * Copyright 2018-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://www.apache.org/licenses/LICENSE-2.0 * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. */ package com.amazonaws.transcribestreaming; public class TranscribeStreamingDemoApp { private static final String REGION = "region"; 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 16kHz, 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 InputStream getStreamFromFile(String audioFileName) { try { File inputFile = new File(getClass().getClassLoader().getResource(audioFileName).getFile()); InputStream audioStream = new FileInputStream(inputFile); return audioStream; } catch (FileNotFoundException e) { throw new RuntimeException(e); } } 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()); System.out.println("Error Occurred: " + ExceptionUtils.getStackTrace(e.fillInStackTrace())); }) .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 static class AudioStreamPublisher implements Publisher<AudioStream> { private final InputStream inputStream; private AudioStreamPublisher(InputStream inputStream) { this.inputStream = inputStream; } @Override public void subscribe(Subscriber<? super AudioStream> s) { if (currentSubscription == null) { this.currentSubscription = new SubscriptionImpl(s, inputStream); } else { this.currentSubscription.cancel(); this.currentSubscription = new SubscriptionImpl(s, inputStream); } s.onSubscribe(currentSubscription); } } private static class SubscriptionImpl implements Subscription { private static final int CHUNK_SIZE_IN_BYTES = 1024 * 1; private ExecutorService executor = Executors.newFixedThreadPool(1); private AtomicLong demand = new AtomicLong(0); private final Subscriber<? super AudioStream> subscriber; private final InputStream inputStream; private 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(); } } }

Sample Details

Service: transcribe

Last tested: 2019-01-10

Author: AWS

Type: snippet

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