Google Cloud Platform: Speech to Text Conversion of Large Media Files

Question

I'm trying to extract text from mp4 media file downloaded from youtube. As I'm using google cloud platform so thought to give a try to google cloud speech.

After all the installations and configurations, I copied the following code snippet to get start with:

with io.open(file_name, 'rb') as audio_file:
    content = audio_file.read()
    audio = types.RecognitionAudio(content=content)

config = types.RecognitionConfig(encoding=enums.RecognitionConfig.AudioEncoding.LINEAR16, sample_rate_hertz=16000, language_code='en-US')   

response = client.long_running_recognize(config, audio)

But I got the following error regarding file size:

InvalidArgument: 400 Inline audio exceeds duration limit. Please use a GCS URI.

Then I read that I should use streams for large media files. So, I tried the following code snippet:

with io.open(file_name, 'rb') as audio_file:
    content = audio_file.read()

#In practice, stream should be a generator yielding chunks of audio data.

stream = [content]
requests = (types.StreamingRecognizeRequest(audio_content=chunk)for chunk in stream)

config = types.RecognitionConfig(encoding=enums.RecognitionConfig.AudioEncoding.LINEAR16,sample_rate_hertz=16000,language_code='en-US')

streaming_config = types.StreamingRecognitionConfig(config=config)

responses = client.streaming_recognize(streaming_config, requests)

But still I got the following error:

InvalidArgument: 400 Invalid audio content: too long.

So, can anyone please suggest an approach to transcribe an mp4 file and extract text. I don't have any complex requirement of very large media file. Media file can be 10-15 mins long maximum. Thanks

Answer 1

The error message means that the file is too big and you need to first copy the media file to Google Cloud Storage and then specify a Cloud Storage URI such as gs://bucket/path/mediafile.

The key to using a Cloud Storage URI is:

RecognitionAudio audio = RecognitionAudio.newBuilder().setUri(gcsUri).build();

The following code will show you how to specify a GCS URI for input. Google has a complete example on github.

  public static void syncRecognizeGcs(String gcsUri) throws Exception {
    // Instantiates a client with GOOGLE_APPLICATION_CREDENTIALS
    try (SpeechClient speech = SpeechClient.create()) {
      // Builds the request for remote FLAC file
      RecognitionConfig config =
          RecognitionConfig.newBuilder()
              .setEncoding(AudioEncoding.FLAC)
              .setLanguageCode("en-US")
              .setSampleRateHertz(16000)
              .build();
      RecognitionAudio audio = RecognitionAudio.newBuilder().setUri(gcsUri).build();

      // Use blocking call for getting audio transcript
      RecognizeResponse response = speech.recognize(config, audio);
      List<SpeechRecognitionResult> results = response.getResultsList();

      for (SpeechRecognitionResult result : results) {
        // 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("Transcription: %s%n", alternative.getTranscript());
      }
    }
  }